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The LB-291/2F Fuel system diagnostic and cleaning equipment
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***This is a very large Technical fuel injection information page***
K, KE-Jetronic System Diagnostic with INTER-JECT click | Here |
EFI System Diagnostic with INTER-JECT click |
Here |
D-Jetronic or MAP sensor click |
Here |
Here |
Contamination of the Fuel System |
Here |

Automotive business success is only YOUR choice!
Let's get the facts now once and for all right in here.

Depletion in engine air velocity after some km the engine has done will reflect into the fuel metering devices.
Those are MAP sensor or Airflow and Air Mass metering devices, which control the engine performance but also deplete the vehicles drivability by being sluggish on takeoff gradually getting noticed as a flat spot. This depletion is actually a narrowing of the pulse-with and injection duration. This means that the factory set fuel curve in the computer chip can not be any longer maintained in the same parameter.
I talking here about electronic Fuel Injection systems as those are more common today than K-Jetronic systems.)


So cleaning Injector becomes USELESS in my opinion, because of that above stated argument.

To investigate the problem a special equipment with 2 flow meters is required to check the system flow that is in the right spec. And secondly to check the injector flow and duration at a set pressure to be able to recalibrate the injection system to the worn engine. (Or simply to say; BALANCE THE INJECTION SYSTEM TO THE WORN ENGINE!)

But before commencing any work a special solvent with color indicators is used to investigate the muchness of contamination in the system before any other work is done.

The operator will gain a visual indication of the entire system in which he can plan his work step by step for a success full 2 part fuel system cleaning and then a 1000% calibration.

This is the INTER-JECT way, we do. Any other services with or without injector removal or just using a cleaner is just not on.

If you put a spark plug on a wheel it still won't go. Or if you do not balance your wheels you will have a steering wobble and by blacken the tyres the wobble will NOT GO AWAY even if you use all sort of brand's in tyre black."

They may look very nice, but the damn wobble will be still there."

   Full diagnostic, cleaning and calibration equipment.

   The LB-291/2F Fuel system diagnostic and cleaning equipment


Low fuel flow is also caused by restrictions in the fuel filter, wrong fittings, and fuel density if the fuel tank is near empty and very hot fuel is flowing through the flow meters seen as fuel aeration. The lack of fuel flow will cause the engine to be fuel deficient when at high speeds and/or under heavy load. It is therefore essential that the fuel system has the correct flow rate. Systems that have low fuel flow could have blocked fuel filters. A faulty pump electrical supply and /or be an early warning of imminent pump failure.

Paramount! You cannot prove the integrity of the fuel delivery system by simply measuring the fuel pressure alone. This is one of the most common mistakes made in diagnosing this system. Fuel pumps produce fuel flow not pressure. The fuel pressure in the fuel delivery system is created by restricting the fuel flow produced by the fuel pump.

Why? Because the Vehicle requires a quality of fuel flow. Bubbles of air or fuel vapour, expanded or dirty fuel or water suspended in the fuel flow cannot be seen without INTER-JECT equipment when fuel is under pressure. Just imagine a bottle of soft drink or beer. You know the bubbles are in there, but you cannot see them until you take the cap off the bottle and release the pressure. Once the pressure is gone, any gas suspended in the liquid instantly becomes visible. The same applies to fuel delivery systems. If air or fuel vapour is suspended in the fuel flow, they cannot be seen when the fuel is under pressure. The most common fault overlooked in the TRADE.


If you have a problem finding Technical information on Fuel Injection on this Website so please send your request to the Webmaster |


K-JetronicK-Jetronic   Quick access links on this page:
                                            | FUNCTIONS AND COMPENSATIONSStarting Cold Starting |
 KE-Jetronic Hot-Start Pulse Relay | Post-Start/Warm-Up Acceleration  |
                                             | Part-Throttle Acceleration | Full-ThrottleAcceleration
I have noticed over the last few years my E-mail Box is getting overloaded with motorist "Help" inquiries from USA, Africa, Russia, India and so on. These inquires are sent to me direct from the INTER-JECT Website daily.

These help requests come mainly from places where we unfortunately do not have an INTER-JECT service centre or Distributors appointed as yet, to send those desperate people to get local help in their locality.

The following E-mail statistics will give you a clear picture of what problems Motorists are seeking solutions for;

5% Engine stopped and does not start at all.
10% intermittent faults of engine missing, backfiring and/or poor performance and fuel economy.
15% hard starting problems.
20% Poor engine driveability and engine stalling on acceleration.
50% K-Jetronic performance problems, poor starting and so on.
60% High emissions and high fuel consumption.
70% Truck problems are mainly Diesel smoke emissions and poor performance.
80% Flat spot, poor idle, engine momentum inconsistent, poor performance etc. This is one of the highest inquiries.
100% of all inquiries are in need of just a simple system Calibration, where the synchronization process is done by running
the Engine and ONLY altering the calibrations according to the visually monitored injector flow rate on the flow meter and
system flow meter!

This will give the operator a picture of the extent of the problem and a guaranteed fix!!

The K-Jetronic problems are poor starting, poor engine idle when cold and so on.
In the following articles there are some E-mail extracts from Motorists looking for a solution to fix their problems which no one has a clue what is the cause or the solution, due to a lack of understanding of the system.

E-Mailed to me from UK.  Audi 90  1990 KE-Jetronic    "What a crowbar JOB by some trades people."
----- Original Message -----
From: mike shenton
Sent: Saturday, January 27, 2001
5:52 AM Subject: I'am looking forTechnical information in .............. ?? E-mail send from sysdiagn.htm

Please Help
I have a audi 90 1990 2.3 with ke jetronic system. One fine day I started the car and proceeded to the local shop about a mile away. On my return could not get the vehicle to start. I took the car to the local specialist who assured me he had the correct gear for testing the pressurised system etc. the first part he said I needed was a injector switch which didnt seem to sove the problem. Then there was the fuel metering head which needed replacing (lucky for me I obtained a 2nd hand part). The car still wouldnt start After more comprehensive tests it was decided that the ECU was faulty. After replacing this expensive part the car now starts but in order to restart the vehicle I was politely told that I would have to lift the air-meter with a scewdriver in order to get going. The mechanic has now after two weeks of trying to sort out the problem used the phase (I am throwing in the towel). A couple of hundred quid later I am still in the same position . ( I would like to point out that this garage is quite a fair size with all the bosch machinery. Thanking you already Mike Shenton torquay devon uk.

Dear Mike Shenton,
Well what can I say? It's not only you get into this problem but 1000's of others as well.

I noticed that you have read my article at because you have send this E-mail of from there.

To help you in this matter is a bit difficult because we do not have any INTER-JECT Agent over in your Country. But to say the least your Mechanic has not done the basic checks and if it is a Bosch Agent it is a bit STEEP to use Bosch'es name as an Umbrella to impress and pretend they know every thing.

Legally you're in the right to ask for a compensation to the NON NESSESARY PARTS REMOVALS in your Vehicle. Those new installed parts are not calibrated to your engine and this is the problem you have to use the screwdriver to lift the sensor plate in the fuel distributor assembly.

!!!!!! What a JOCKE.!!!!!!

Would you be so kind and point my above mentioned Website to your Experts and tell them that this is a matter of Professionalism to work on K-Jetronic systems and it is not a job for Butchers using crowbars for fine adjustments.

||||| Only with your permission by E-Mail I would like to publish this Letter on the above mentioned Webpage.|||||

Kind regards

Leo Karnauchow

Dear Leo
You may use my letter on your web site. I have now taken the car to an affiliated Audi dealer. I will keep you posted

Mike Shenton

This is typical and the most common problem where most people get really and unnecessary in trouble.
They're where the INTER-JECT Equipment is required to do a 10-minute satisfying system Calibration. "Hey only 10-minutes!! "

----- Original Message -----
From: tom and/or tracy rhoden
Sent: Tuesday, July 11, 2000 3:51 PM
Subject: I'am looking forTechnical information in .............. ?? E-mail send from sysdiagn.htm

Have a 90 vw fox with ke-jetronic{cis}. It started running rough cold but would clear up after about 1 minute of driving. I was willing to put up with this until I started it one hot afternoon and it was running so rich that it barely would accelerate. I pulled into the shop of the chrysler dealer where I work to check it out. I cleaned the spark plugs and restarted it with the same symptoms. It seemed to be corrected after we applied vacuum to the fuel pressure regulator attatched to the fuel distributorAfter doing some reading I discovered that the pressure regulator is vented to atmosphere and doesn't require vacuum.After that it still ran rough for a minute in the morning but was acceptable otherwise. Then this weekend it started running rough at idle once warmed up. I cleaned the ground cables on the side of the battery box and replaced the 6 year old battery since it was becoming a source for corrosion. I had to replace the + and - battery cables in January when I bought the car. I also cleaned the throttle body idle passage and butterfly's also this weekend. The car ran better and smoother this morning than it has in the 6 mos. I have owned it. Thought I was done. then on the way home to day the idle would drop to 0 and stall unless I pressed on the gas. It was difficult to restart. The problem[s] seem to be temp related either cold running or after 25-30 minutes of driving in hot weather. I have checked the two pronged temp sensor and it reads 300-400 ohms cold and goes over 2000{the max my meter will read] hot. the only tech info I have been able to find is for bosch systems with electronic injectors and the scale is the reverse of the readings I have with my temp sensor. I need definite info for the temp sensor for my system. I suspect that the temp sensor is going to open circuit warm and causing the the car to die. I am also suspect of the heated 02 sensor since the cold running will improve if I disconnect it.Any info or or suggestions would be appreciated. thank you, Tom

Dear Tom,
Thank you for your enquires about INTER-JECT You have sent me the e-mail help request from
I know you have read those information on that page about K-Jetronic miss calibration once your car's has reached 100 000 km or more on
your speedometer.

You said your self  "It started running rough cold but would clear up after about 1 minute of driving. I was willing to put up with this until I started it one hot afternoon and it was running so rich that it barely would accelerate."

This is typical the problem I'm screaming into the world the last 15 years, but no one does understand or is not willing to do something realistically about. Instead people start fiddling with things which is not the problem that is causing the bad idling flat spot and so on.
This is a non-visible problem. You can not see it, and you can not find it as it is totally invisible same as a magnetic force.

You know it is there but you can not see it unless you use metal dust over the top of the magnet. This is the ground floor principle how K-Jetronic has been invented way back in 1962 but I do not want to go scientifically into it. However
look on to the equipment closely with its turning float indicators. They are here to show the operator the way what mystery is going on inside the K-Jetronic system or EFI system.

This is like I mentioned before; magnetic force is only visible with metal dust or a Compass.

The Pilot or Ship Captain finds his way around the world with the equipment called "COMPASS".

No what's happen to your bad engine Idle? It is the same, the Mechanic finds "ONLY" his way around with the INTER-JECT equipment and that's the end of story.

Since you work in a Chrysler dealership, well point out to your management about this system we have to offer.

We are World leaders in fuel injection calibrations and we have in many progressing countries our Superior INTER-JECT technology. As you are Interested in the INTER-JECT Products and Services, I would highly recommend due to past case histories for your EFI vehicle to use INTER-JECTRON to avoid sulfur burns on Valve seats see attachment.

The symptoms are bad engine idle, engine vibrations, and intermittent pops into the exhaust progressing gradually to be almost constant at engine idle. Most Mechanics's overlook this, but after spending huge amount's of $$ in replacement parts you only find out the hard way by not having any results to have the problem cured.

As I noticed you are from the USA because you mentioned Chrysler dealership.

We just have only one INTER-JECT service centres set up which is
Daves Auto Repairs
17725 52nd Ave Ct E
Tacoma, Wa 98446
Phone 1-253-847-2437
Fax: 1-253-847-2468
For your interest Tacoma is 50 miles from Seattle.

We have no Distributors in your country but we looking for someone to become our Import Agent in your country.
However you can obtain the INTER-JECT Products via our Website.
By the way, JAPAN has found INTER-JECT as the only solution to add performance to vehicles and keep pollution to a minimum.
See here

Read about the profitable highlights and benefits from the INTER-JECT equipment including the associated products at

I'm still writing on my special K-Jetronic Article at: it's this page you on it which is for the
secret data pool, but still held outside for you to have a look, as you will see what I mean!
Many similar articles are hidden in a special Data pool for machine holders.

You can't beat INTER-JECT experience, the quality equipment and products.
Eventually everyone has to have this type of service done for superfine tuning the electronics to the worn engines.
NEVER been done before and Vehicle manufacturers would rater wish you don't know about this.

End user information you will find at,
See more in,
By all means contact me again, if you require more information.

Kind regards Leo Karnauchow

| Click here to see more desperate letters |

I have received 1000's of similar desperate K-Jetronic E-mail letters from all over the world of exactly the same nature!

What is it that is causing the fuel injection system to get out of CALIBRATION to the engine ?
That's what it is... !  Simply out of calibration :]

K-Jetronic, is a system which has a control pressure regulator or on the KE models it is the electronically controlled pressure actuator which is used to change the counter line pressure of the metering pin inside the fuel distributor. These units are factory set to the new engine and stay that way for the life of the vehicle. Once the engine vacuum degrade because of piston slap, piston ring wear or valve leakage, or a blocked exhaust or melted catalytic converter (this is what I call a mechanical fault).

The other is a contamination fault, which is air restriction to the engine by carbon on inlet valves, a change in the fuel flash point (no name fuel, cheap backyard fuel diluted with kerosene) and restricted or clogged injectors.

Or a combination of both, Mechanical and poor vehicle maintenance!

All this will automatically alter the factory synchronization. The intake air pressure on the air sensor plate is no longer the same, unable to lift the metering pin to the correct level to provide the correct fuel mixture for the engine when it is cold.
(It doesn't matter if you alter the height of the sensor plate by the mixture screw to have the right mixture because: ++ the HYDRAULIC counter pressure ++ is still the same!!)

The factory set fuel control pressure regulators sole purpose is allow the lifting of the metering pin in the fuel distributor. (Which is moved up or down by the sensing plate arm.) Only as far as the fuel ratio requires and is precisely synchronized to the incoming air ratio and also to the warm up time of the engine and the thermal heat/plus electrical BI-metal heat to the regulating valve inside the control pressure regulator.

This is similar to a water tap in a pressurized line. By fully opening the tap, a flow is created with hardly any pressure in the line, which could counteract a little bit to read the pressure gauge (depending on line friction). By slowly closing the tap the flow will reduce and causes a counter pressure in the line to move the pressure gauge needle to a higher reading.

If the tap is closed fully there is no flow but a full counter pressure where a full line pressure reading can be obtained from the gauge. This is exactly how this control pressure regulator works!!

Further enhancements are vacuum control pressure variation to alter the counter line pressure to the metering pin. This is to avoid hesitation on acceleration, or electronically stabilized CO readings by dithering the electronic pressure actuator to dump off fuel counter pressure or increase the fuel counter pressure to the oxygen sensor signal value to lean out the fuel mixture ratio and so on.

What is this line counter pressure actually doing in K-Jetronic???
ay your engine is cold and as you know a cold engine requires more fuel to run than a hot engine?
So you simply can't have 2 systems that work as;
System (1) for a cold engine and system (2) works for a hot engine and it would be a flint-stone invention.

So the ONE system has to do the lot, it must be able to synchronize itself to the warm up parameters and the fuel mixture requirement, when cold, warm or hot. It must be able also to respond to the drivers' actions of acceleration, cruise plus it must respond to the oxygen sensor as well.

So this is a hell of a lot of work to be exactly spot on for a control pressure regulator.

What it can't do is to synchronize itself to compensate for worn out engine tolerances, that's
where the INTER-JECT equipment is used to excellent effect by the fuel injection technician.

Don't you think so ??
You better believe this because this is the problem with your car, because your control pressure regulator works only for a NEW engine ! How old is your engine now?

Now I think the penny has dropped! But not quite, read on because there is more to this than you may think!

ou've seen how each control system adjusts the basic air-fuel mixture. Now you'll see how other components add additional enrichment as necessary.

hen the key is turned to start, the fuel pump is turned on through the safety circuit to build up system pressure; if the engine stops turning for more than one second (as when the engine will not start) the pump shuts off, even with the ignition key on. For starting enrichment, extra fuel is delivered to the port injectors. In K-basic and K-lambda, reduced control pressure allows more plunger lift, increasing slit size to deliver more fuel. In KE systems, the control unit sends more current to the pressure actuator for start enrichment, lasting about one second. The current is high for maximum pressure drop at the metering slits, enriching the mixture delivered to the port injectors.

Cold Starting:
or cold starting, in addition to enrichment at port injectors, continuous systems enrich the mixture with a cold-start injector system, similar to that used in some pulsed systems. Also an auxiliary-air valve or idle-speed stabilizer adds air, bypassing the throttle plate to increase idle rpm. (((This will be the first sign of a air-velocity loss if the idle degrades, and the engine stalls)))
Beginning about 1985, some KE systems ground the start injector through the control unit, so the thermo-time switch is eliminated.

Hot-Start Pulse Relay:
ome cars-notably BMWs, VWs beginning about 1985- have a special hot-start pulse relay. The relay bypasses the thermo-time switch and grounds the cold-start injector in short pulses when a warm engine is started, spraying fuel into the manifold. This provides additional fuel in the intake manifold to aid starting when the port injectors are delivering less fuel because of high temperatures and vapor in the lines.

hen the key is released to run, enrichment changes from engine-crank. This starts from here and monitored from the actuator by gradually decreasing the mixture. On K-basic and K-lambda the control-pressure regulator warms up, gradually increasing control pressure on the top of the plunger. This cuts back the enrichment factor in a few minutes.

n all systems, rapid opening of the throttle increases airflow velocity and causes the air-flow sensor plate to overreact, but if the engine has done high mileage this causes air flow velocity degradation and there will certainly be NO sensor plate overreaction. In the same manner this is similar to that of pulsed systems vane-type air-flow sensor flaps.
Overswing of the sensor plate allows the plunger to momentarily rise higher and enriches the mixture enough to prevent lean-mixture flat-spots and hesitation.

Part-Throttle Acceleration:
n K-basics and K-lambda, cold engine overswing is greater than that on a warm engine because reduced control pressure on the plunger allows more lift. In addition, some control pressure regulators sense manifold pressure to further reduce control pressure and add acceleration enrichment.
KE systems use an additional sensor, the sensor-plate potentiometer (also called the air-flow sensor position indicator), to signal the need for extra enrichment during cold-engine part-throttle acceleration. The potentiometer signals how fast and how far the sensor plate moves as air flow increases.
The potentiometer has an arm with sliding contacts that is connected to the sensor-plate pivot. As the arm moves, it changes a voltage signal. From this input, the control unit sends a compensation output to the pressure actuator. For about one second, pressure-actuator current increases, depending on sensor plate movement and on engine temperature and rpm. The greatest enrichment is when the engine is cold; middle enrichment when the engine is cool; no enrichment when the engine temperature is above 175 F (80C). Mercedes, and Audi has added an intake Air Temperature Sensor to further compensate acceleration-enrichment for cold air, a refinement for better driveability.

Full-Throttle Acceleration:
n K-basic and K-lambda, enrichment is supplied only on systems with control-pressure regulators linked to manifold pressure. KE-enrichment usually continues as long as the throttle switch signals a full-load condition, adding enrichment by control of the pressure actuator. Some engines, particularly VW, need full-throttle enrichment only during limited rpm ranges, so the control unit is programmed accordingly. The control unit adds about 3 mA to the actuator current to compensate the mixture for full-load acceleration, depending on the full-load signal, on rpm and engine temperature.

So basically speaking, if your engine has compression losses, air-leaks, or air-flow restriction due to carbon build up which is paramount to KEEP all the factory set calibrations. This is so vital to have all the necessary control elements in an optimum synchronization.

Plain and simple; this is exactly the same , if you have a flat battery you have trouble starting your engine!

CALIBRATION Checks and resetting the system to the worn engine:

System diagnostic in flow and pressure before calibration

A  INTER-JECT LB-291/2F with precision flow meters.

B  Engine RPM and Performance alteration (diversion valve) to magnify problem changes to pin point, exact counter hydraulic ratio to the available engine air velocity at certain pressure settings!

C  Upper diversion valve to run 2 flow meters at the same time in various checks.

D  Ball switching valve on the back of the equipment. (it is as part of the equipment)

E  High pressure cylinder and solvent reservoir.
F  Air bleed, or also used to put flow indicator on an liquid/air cousin for more sensitive pulsation diagnostics, or remove dirty fuel samples out of the fuel flow ect.   G  3 way selector ball valve (optional) only used on K-Jetronic's and on solenoid Diesel injection.

Let's see a simple formula for a brand new vehicle:
Say your engine is Brand New, dead cold and at idle. Your air intake pressure is 3 pounds. Sensor plate is lifted 2,5 cm by the air pressure velocity of the engine and low counter pressure. The counter pressure regulator is set for this engine at the factory to 1.5 kpa At this setting, the engine starts smoothly, the metering pin holds the fuel ratio to 14.1:1 Engine idle is held to 1000 rpm. also due to the air by pass valve.

Next: Say your engine is Brand New, but hot now and at idle. Your air intake pressure is 2.5 pounds. ( a bit less as it is cold) Sensor plate is lifted 2 cm by the air pressure velocity of the engine and high counter pressure. The counter pressure regulator is set for this engine at the factory to 1.5 kpa cold but has now moved to 4.5 kpa At this setting the engine runs smoothly, metering pin holds the fuel ratio to 14.1:1 but it is in a lower position due to the counter pressure. Engine idle is held to 800 rpm. also due to the nearly closed by pass valve.

Let's see a simple formula for a vehicle with 50000 km on the clock:
Say you engine has 50.000 km, dead cold and at idle. Your air intake pressure is 2.5 pounds. (lost .5 of a pound)
Sensor plate is 2,2 cm lifted from the air pressure velocity of the engine and low counter pressure (lost .03 of a cm.)
Counter pressure regulator is set of this engine at factory to 1.5 kpa (No Change at all same as the engine NEW)
At this setting engine starts wobbly, metering pin is held to fuel ratio 13.1:1 (Air velocity loss due to old engine)
Engine idle is held to 975 rpm. also due to the air by pass valve. ( also the result due to loss of air velocity)

Say you engine has 50.000 km, but hot now and at idle. Your air intake pressure is 2 pounds. (less as in cold but lost .5)
Sensor plate is 1.8 cm lifted from the air pressure velocity of the engine and high counter pressure.(lost .02 of a cm. )
Counter pressure regulator is set of this engine at factory to 1.5 kpa cold but now moved to 4.5 kpa (NO Change at all)
At this setting engine runs so, so, metering pin is held to fuel ratio 13.1:1 but is in a lower position due to the counter pressure.
Engine idle is held to 750-800 rpm. also due to near closed by pass valve .( also the result due to loss of air velocity)

Let's see a simple formula for a vehicle with 100 000 km on the clock:
Say you engine has 100.000 km, dead cold and at idle. Your air intake pressure is 2 pounds. (lost 1 pound a lot from NEW)
Sensor plate is 2 cm lifted from the air pressure velocity of the engine and low counter pressure (lost .5 of a cm.)
Counter pressure regulator is set of this engine at factory to 1.5 kpa (No Change at all same as the engine NEW)
At this setting engine starts bad stalls etc., metering pin is held to fuel ratio 12.5.1:1 (Air velocity loss due to old engine)
Engine idle is held to 900 rpm. also due to the air by pass valve. ( also the result due to huge loss of air velocity)

Engine 100.000 km, hot and at idle. Your air intake pressure is 1.5 pounds. (less as in cold but lost 1 pound from NEW)
Sensor plate is 1.2 cm lifted from the air pressure velocity of the engine and high counter pressure.(lost .08 of a cm from New)
Counter pressure regulator is set of this engine at factory to 1.5 kpa cold but now moved to 4.5 kpa (NO Change at all)
At this setting engine runs bad, metering pin is held to fuel ratio 12.5:1 but is in a lower position due to the counter pressure.
Engine idle is held to 750 rpm. also due to near closed by pass valve .( also the result due to loss of air velocity)

Got the picture now ?? YOU UNDERSTAND!!

The engine Air velocity changes by the aging engine, it looses the vacuum consistancy by not having the strength to counteract to the factory parameter setting of the control pressure regulator. The control pressure regulator in an NEW Vehicle is in the same parameter setting when the engine is old or has driven past the 100 000 km.

Nothing changes the control pressure regulator hydraulic counter pressure force value when the engine is aging.

But lots of things can change air velocity deficiency in a NEW engine and also in an old engine!

For instance a blocked air filter, carbon on inlet valves, valve adjustment, or valve stem wear, camshaft wear, blocked exhaust, wrong muffler installed on a BMW, Mercedes Benz and Audi's DON'T you dare install supermarket mufflers on those cars!

The other interference is the loss of good engine momentum to create the required suction for the air velocity is as follow.
A change in the fuel flash point (no name fuel, cheap backyard fuel diluted with kerosene) or restricted or glogged injectors, dirty fuel, water in fuel, worn valve guides, engine blow by, ignition breakdown or a combination of both, Mechanical and of the poorly maintained vehicle! This will only add to all those above mentioned problems.

Calibration set up to pinpoint values for final fixture.

Under running engine the diversion valve B is slowly opened to by pass the control counter pressure return flow back into the fuel tank via the orange temporally external return line outside the vehicle. Gently bringing it into balance with the aid of the flow meter's and pressure gauge by easing off the factory set counter pressure to the metering pin in the fuel distributor. Only this way, by the strictly gentle opening the by-pass on the equipment will ease off the in position held metering pin allowing the air sensor plate to move up. The worn engine air velocity has now the chance to lift the sensor plate to that new required level where the engine idles at its best at the 350 kpa. setting. The flow indicator has to be monitored to all levels because the pressure gauge is no more longer sensitive enough to show an 100% balance matching between:- (1) temporally set system pressure to 350 kpa, (2) best idle position to be longed to flow indicator position. By closing B diversion valve flow meter will go up 2-3 cc/min or even off scale on badly worn engines. This will only indicate to the operator "how much the injection system is out of balance to the engine vacuum's requirement" ! After that its only a matter of physically setting the counter pressure flow, to that exact flow meter indicator positioned before. The diversion valves on the equipment remain closed. The engine will run then on the new balance setting like a purring cat. More about red in | here |
                All links are on this page and you can scroll up or down, back here where you left the point of action!)

Your Question is now:- Why not adjust the mixture on the sensor lever and it's done with it!
My answer is:- NO- it is not done with it, because that's only an mechanical set up to the value of air and fuel ratio to keep the metering pin held inside the fuel distributor to the synchronized order of the engines air velocity at all cost!
The "variable control pressure segment" only governed by the control pressure regulator is not adjustable by the end-users or mechanic due to the complexity, not have gained the know how or the equipment to do this gentle fine tuning.

Your Question is now:- By easing off the control counter pressure, the sensor plate lift higher to an richer level. Now if I adjust that sensor lever arm mechanically back to the required air and fuel ratio I' m back there where I started. So what is good about the whole exercise anyway??

The Fuel-presure counterforce and Air-flow force.

My answer is:- You right it is like you chasing your tail! For an example an aircraft fly's at 10,000 feet and is descending down to 1000 feet of an descending rate of 500 feet per min. What are your EARS? doing. What is now adjusting your ears to that pressure to counter act the pain??

The aging engine has no counter reaction for engine air velocity losses, nor the fuel components in an factory set envolope can hydraulically re-adjust it self for a new setting to compensate for the air pressure/velocity losses.

So because you have to re-set your mixture ratio to the metering pin by the mixture screw, after the hydraulic calibration is

Set up diagram of pressure counter force and air sensing.

done, this means you don't chase you tail to be there where you started form, because you did not realize the whole sensing mechanisms is now moving more unrestricted and freely in that worn engine air stream!

INTER-JECT Twin-flow and pressure diagnostic equipmentThere are only the following benefits for your vehicle:
Easy starting, better idling in the warm up period, smooth engine momentum on acceleration from low, right out in the high range, much more zippy in traffic, flat spotting is gone, back fire is gone, engine roughness is gone, missing is gone, stalling is gone, HC smell is gone, lagging on take of is gone, unbalanced idle is gone, engine hunting is gone. idle stabilizer valve has better control to your engine speed set parameter. It runs virtually like a new engine even it has over 100 000 km on the clock!
Don't you ever try to alter the counter pressure by guessing without flow meters. Pressure gauges are not sensitive enough to give you the finer points in the relationship of air flow pressure and sensor plate lift. Plus pulsation signal readings and variations to the pressure actuator controlled by the ECU on KE-Jetronic.

A wrong shifted control pressure setting could result in no engine start when cold, or diluting the engine oil with fuel. So don't try it because the tolerances are too fine to be monitored by hearing or pressure gauge.

See for your self the [Synchronization Test ] ( A new Window will open over this page! )

Is there a fix ? The answer is YES! 100%

How is this fix done? Additionally to the description above it is simple, so simple that the vehicle manufacturer does not want you to know! That is why you got the problem and you reading my article to find the solution to your problem.

For example, if you got a steering wheel wobble, you balance the worn tyres to the wheel with counterweights to keep them in balance for a smooth ride!'s the same you balance the fuel injection system to your worn engine and every problem you have is gone 100%
Make SENSE ..........??

Or the alternative is, buy a new engine and everything's is good again, that what the vehicle manufacturer want anyway!

Can I buy a new control pressure regulator?

The answer is yes, but it does not fix the problem, because they are all factory set for a new engine. Also all L-Jetronic flow meters, LH-Jetronic air mass meters, D-Jetronic MAP sensors, Karman Vortex Ultra sound air meters etc.
What is the point spending money which does not fix the problem anyway.

What do I have to do to balance my fuel injection system to my worn engine?

1. Check and set all values to fuel FLOW consistency of your vehicle first ( read here) this is paramount!
(All links are on this page and you can scroll down back here where you left the point of action!)

2. All settings require 100% integrity in fuel delivery as this will be the foundation of new settings.

Fuel pressure counter force

Fuel flow must be to our specification as this has to drive the equipment where everything must balance like your accounting figures.

3. The fuel flow in the equipment drives an system flow indicator to an master setting, by altering the fuel counter pressure force, the master setting will change to a different level due to diverting the fuel off from the flow channel of the equipment.
With the by pass valve the idle will be lifted or lowered by changing the counter pressure to find the new calibration level to the engines lost vacuum/air velocity force.

4. This will change the whole segment form cold to the warm range in the control pressure regulator.

6. By running the engine the system is totally controlled from the LB-291/2F INTER-JECT equipment. It's magic its like a by pass heart/lung machine from a Hospital, the car runs the way you set it on the equipment by pass valves.

(That's it, the engine runs on by pass mode set to the value by the operator from the equipment!)

7. He visualize, simultaneously, injector flow the fuel what the engine consumes at idle, system flow, what the pump puts out, system pressure required, counter pressure to the metering pin, and flow and many more important things required.

8. All this can be now with the equipment valves manipulate to get the car running the way the operator want it or the customer

The control-plunger and its barrel.

is happy with. Once all is set on the equipment and every one is happy, the meter readings will be logged at this point they are! Then the by pass valves on the equipment will be closed and all is back the same way the car was. It runs on its own system again but the meters been now driven to a completely different position.

9. NOW its easy, the operator alters the calibration setting inside the control pressure regulator, fuel distributor etc., without touching the by pass valves on the equipment! The flow meter and pressure reading will be put back to the logged position by calibrating the vehicles components.

10. That's done simple with no drama. The result is 100% because it is not the mechanical part causes the problem here.
It is the hydraulically part which caused the problem ( Too much counter pressure, leaning the engine so much out to bad idle, luck of performance, hart starting, flat spotting, keep food on accelerator to avoid an engine stall and the list goes on!

Can I do this Job on my car, I'm not a mechanic?

The answer is;  YES!

With the INTER-JECT Equipment LB-291/2F and my instruction manual, access to the secret data pool and total On-line E-mail customer back up you will be the master in your own rights!

Can I do this Job without this INTER-JECT equipment ?

The answer is;  NO!
You can not find the 7 synchronization points simultaneously by running the engine which is;
1 System fuel flow., 2. Injector flow., 3 Counter pressure discharge flow, 4 System pressure, 5 Counter pressure, 6 balance setting between air flow, and the above mentioned parameters., 7 monitor mixture and idle requirement at all times by the running engine. This is only a part for K-jetronic calibration requirement but is more for EFI calibration requirement.

Is there a similar equipment on the world market?

The answer is;  NO! Only INTER-JECT is solely the inventor and manufacturer of this system and the techniques!

Is the INTER-JECT equipment and service in the USA, Russia, Africa available?

The answer is:  NO!
We do not have any INTER-JECT service centre or Distributors in USA, RUSSIA, or AFRICA appointed as yet,
but we are looking for someone to establish INTER-JECT in those countries.

As you know this is just a start for the ever growing Motorists problems in EFI and K-Jetronic calibration matters and fine tuning the fuel systems. ( Proof are the daily E-mails I get and I'm sick of it to write over and over the same thing)

The same way as we doing this in GERMANY, (winning the highest award ever an Australian company achieved) Japan has just launched INTER-JECT Japan, Indonesia, Singapore, New Zealand, etc.

This would be the best ground floor BUSINESS for any one in the automotive trade or for some one in general sales, why not look deeply into our system which we offer world wide. You would have something in your hand which makes life easier by visualizing vehicle problems and is so easy to correct those problems by bringing real satisfaction to your customers and your self.

There are also a number of other countries open for INTER-JECT Distribution.

Electronic Fuel Injection
    Note: Links in this section lead only to pictures. A new browser window will open over the top of this page which can be closed or minimized for further references if required.

To enable electronic fuel injection [EFI] system's to function correctly accurate metering of fuel in accordance with the mass of air inducted or forced into the cylinders is necessary. It is paramount at all cost, to keep carbon away behind inlet valves!! Air filters must be clean! Otherwise this fools the airflow meter, and the air flow meter fools the ECU. On hot wire sample port air-mass meters, backed in dust particles on the element become a heat shield, degrading the correct air sensing ability, which causes a flat spot. This fools the ECU of inhibiting the acceleration enrichment that in some case the engine backfires into the intake manifold. This problem is only fixed by submersing the hot wire element into INTER-JECTRON. A new calibration setting must be done after the element is clean to match up the air velocity losses of the engine as described in the data-pool section "Air flow meter".

This air sensing is achieved by a number of various air flow meters, (MAP sensors is a manifold absolute pressure sensing device to change this pressure variation to electronic signals for the ECU to process, see D-Jetronic.) which measures the flow rate of air used by the engine and signals the computer. The higher the rate of air flow, the higher the voltage signal to the EFI computer, and vice versa. The computer uses these signals to regulate the duration of the injection of fuel into each cylinder, thereby maintaining the air/fuel ratio as close as practicable to the stoichiometric ratio of 14:1.

The air flow meter uses one of three methods to measure the air flow rate of the engine; the flap type meter,  [link to picture]
which utilizes a sensor flap attached to a potentiometer; the hot-wire type flow meter, [link to picture] where the computer measures the voltage required to keep the platinum wire in a heated state, and the vortex type flow meter, which uses ultrasonics to measure air disturbance in the flow meter. There are some other type of air flow meters as well with enhancements, hot film, sample port, etc. In the flap type air flow meter [link to picture] , air flowing through the bore of the meter, acts against the sensor flap, forcing the flap to move and open the bore of the meter to a point where the air flows without restriction. When the flap moves, it also moves the wiper arm of a potentiometer, which changes the signal voltage to the EFI computer. The computer then alters the duration of injection in proportion to the volume of air flow. The hot-wire air flow meter utilizes an extremely thin platinum wire located in the air stream path within the bore of the air flow meter
[link to picture]. When the engine is started, a current is supplied to the air flow meter to heat the platinum wire. With the engine at idle, the heating current is approximately 500 milli-amperes [mA]. When the engine is accelerated, the air flow over the hot wire increases, cooling the wire and dropping the resistance. The computer immediately corrects this situation by increasing the heating current, returning the hot wire to its original temperature. At the same instant the computer increases the duration of injection in proportion to the air mass passing through the air flow meter. These changes take place within a few milliseconds and before the increased air mass reaches the cylinders. The vortex type air flow meter [link to picture] uses ultrasonic waves to measure the air mass flowing through the bore of the air flow meter into the engine.

To enable accurate calibration of the air mass to be achieved, the air passing through the air flow meter must be stabilized i.e. vortices, swirling and eddies must be removed from the flow of air before it enters the air flow meter. This is accomplished by a honeycomb air flow regulator, positioned at the inlet of the air flow meter . A vortex generating rod, placed in the regulated air flow stream, creates asymmetrically but regular vortices downstream of the rod [link to picture]. The created vortices modulate [change] an ultrasonic wave, which is transmitted across the airflow at a constant frequency by the transmitter. The modulated ultrasonic waves are detected as a rich or lean condition by the receiver and converted into pulses by the modulator. The pulses are then analyzed by the ECU. If a rich or lean condition has been detected, the ECU alters the fuel injection duration accordingly; i.e. pulse frequency increases due to increased vortices being generated by a larger airflow across the vortex-generating rod.

So what makes the engine idle, performance fuel consumption etc. degrade??

ell as mentioned in the K-JETRONIC article above, the same happen here mechanically or electronically, there is an factory programmed parameter in the fixed-value memory (ROM) (Read-only memory)

Here, all programs (soft-ware) and all characteristics curves, theoretical values, etc. are stored permanently.
They are " burned " into the ROM-IC, cannot be altered and are designed for the specific application.

This is a fixed Parameter segment, where the Vehicles Engine and Fuel Management reads the start up operating data. (The original Master Instructions to the Engine when it was NEW designed by the manufacturer.) And is then writing the actual faulty data from the sensors into the Random-access memory as a secondary Operating Instruction (RAM) to be used through the vehicle journey.

Pulse amplitudes and shapes are stored so that they can be processed by the microcomputer for optimum performance and fuel economy. The Operating-data memory (RAM) (Random-access memory) where fooled data signals are delivered by the dirty sensors. Lost air-flow pressure etc. will be stored until they are summoned by the microprocessor or super-seded by more recent data, (e.g. from clean sensors, or the good airflow pressure to the combustion chamber, the engine speed sensors etc.)

Data are erased when the system is switched off and must be continuously updated during operation. Intermediate storage of calculated values for subsequent processing also occurs here. This is the variable Parameter segment, where your Vehicles Engine Management can be well and truly DE-OPTIMISED.

RAM data of air-force flow do NOT match up with the (ROM) (Read-only memory "factory fixed" data)
to the air-force flow parameter, to be able to change values.

This is a good example from a desperate EFI car owner from USA.

Re: desperate car owner looking for help
Hello, my name is christine and from the united states. i'm hoping you can lead me in the right direction so that i can finally fix my car and stop being scared of driving it.

Three years ago my car was in a 'wreck'. it went over a cement median on all four tires. i had the oil and transmission pans replaced. ironically, since then my car will stall out durring the hot weather months. usually on a decend or braking and/or idle. i can tell when i start my car at times it will start rough. if i tap the gas pedal it may 'putter'. i turn it off and restart and usually runs smoother. when i drive it, i can tell that at times it doesn't have the power it should and usually stalls near after. if i restart it in nuetral (mainly when i'm in traffic) it'll continue to stall. but if i restart in the park position and turn the key back to the cold start position, it usually runs fine after that.

I have had numerous diagnostics done and every body comes up with nothing. no computer codes show up so they can't pinpoint the problem. i have had the main computer temporarily replaced to see if that was the problem. it wasn't. i have had the fuel pump replaced and fuel injectors cleaned. i believe they also checked the sensors and supposedly came up fine. this is a intermittent problem so when they drive it, it runs fine. my car may run fine for weeks then act up on several occasions, than run fine then act up again.

I emailed to one of those online auto advise sites, they mentioned i may have a faulty fuel pressure regulator. my dealer says probably not, that they are either good or bad and not normally intermittent. i believe that they checked that sensor in previous times.

Please help, any advise or direction would be greatly appreciated.

Thank you


Your question is now: - How do I get my car fixed to stop those problems?

The answer is simple: - Find someone who have the INTER-JECT Equipment and the INTER-JECT knowledge to get your car checked over by setting the system to your liking! For more inf. and the start into the right direction is only in here.
( Read here)

A fuel system similar to K, KE-Jetronic in fuel pressure and direct injector flow, but a fully electronically controlled system with the differences of INJECTORS prolonging into the combustion chamber exactly like the diesel solenoid injection system.

| Click here for INTERJECT LB-291/2F hook up diagram |

All other technical information for this system you will find in the Members Data pool.
Want to see a sample page of Direct Injection? | Click Here |

D-Jetronic (MAP Sensor)

(All links are on this page and you can scroll up or down, back here where you left the point of action!)
Or use your BACK button on your browser to come back to this section of topic selection!


Grouped injection is more commonly known as D-Jetronic. D-Jetronic was the first of the Bosch pulsed injection systems. The most recent cars with Bosch D-Jetronic were the 1975 Volvo 164e and the 1975 Mercedes 450. In 1976, both changed to K-Jetronic. It's most interesting to see how L-Jetronic evolved from D-Jetronic. At the 1967 introduction, Bosch called it ECGI, Electronically Controlled Gasoline Injection, contrasting this new electronic system with a long background of mechanically driven injection pumps. In 1968.69, VW square backs, fast backs and the Kharman Ghia 911E also had this type of injection system. Based on a cross licensing of the Bendix Electrojector system, which was briefly used in the U.S., D-Jetronic depends on sensing manifold pressure as an indication of engine load.

You can refer to the L-Jetronic section for details concerning most of D-Jetronic.

The major differences in the 1968 until now are: -
1. Manifold-pressure sensor, senses engine load.
2. Trigger-contacts in the distributor synchronize injection pulses. (No more used from 1990)
3. Injectors are operated in two groups: - ----- 4-cylinder, 2 groups of 2:
VW, Porsche, Saab, Volvo ----- 1976 2.0 Porsche 914 in the U.S. also has D-jetronic injection.
6-cylinder, 2 groups of 3: Mercedes, Volvo -----
8-cylinder, 2 groups of 4: Mercedes.

Although MAP sensors in vehicles have become popular again, due to less malfunctions, it was regarded by Bosch that manifold-pressure sensing was a less accurate measure of load, and measuring air flow as in L-Jetronic, and in K-Jetronic, or measuring air mass as in LH-Jetronic was more accurate.

For certain Bosch racing applications, however, manifold-pressure sensing is sometimes used. Manifold-pressure sensing is widely used by GM, Ford, Chrysler, AMC, and some Toyota's.
For years after the initial introduction of D-Jetronic, the trend has been away from manifold-pressure sensing. (But not quite read on below)

Common Faults:
he diaphragm (Metal Disc mainly copper material) in those large manifold pressure sensor splits around the moving channel causing an extremely rich mixture and high fuel consumption.
This is noticeable when it is at its extreme that the exhaust tailpipe is wet or oily and the oil level in the engine is higher than normal.

A split vacuum hose on the sensor or on the manifold will to the same thing and is cheaper to replace the hose then this sensor.

Now with the technology in fine micro processing, things look a bit different:


Conveys information on manifold pressure versus atmospheric pressure.
A kinked or perished hose, or leak in the hose to the MAP sensor may cause rich running, rough idling and poor performance.
Note: Carbon build up in intake valve is to Blame.
Service every car with the INTER-JECT LB-291/2F servicing technique and keep the fuel conditioned with INTER-JECTRON.

Hesitation on acceleration. Poor idle. High fuel consumption. Stalling.

TESTS: - With key on engine off at SEA LEVEL an EEC 4 should show 5 volts. With engine running the voltage will vary from 1 to 5 volts depending on load. May be checked using a tachometer or scope. The MAP sensor readings can be out of calibration due carbon build up on the back of the inlet valves. By using the INTER-JECT servicing equipment, the MAP sensor restores its reading automatically to normal

Common Faults:
n extremely lean mixture, what ever the cause maybe, will load up the Ignition Spark capacity which destroys the Coil pack's Distributor cap, rotor, ignition leads and the next is deadly to your MAP sensor, which is a backfire into the inlet manifold. Further burning out the valve seats cause combustion-sealing problem adding to the poor idling characteristics.
Burned, bend, or leaky valves causing poor idle characteristics in any type of fuel injection system and any engine. The same applies for excessive oversizes in valve guides. The next is a slight head gasket leak.

Another very and I have to repeat again VERY common problem is damaging the MAP sensor by a backfiring engine into the manifold.

The sensing plate pushing onto the crystal will be bend into the negative way into the lean segment. The result is then a hunting engine idle, hesitation, poor idle characteristics.

F O R   T H E   I M P E R I A L I S T S
Say the engine is idling at 16 inches of mercury or say 8 psi vacuum.
It should have that (minus) - 8 PLUS 40 psi = 32 psi fuel pressure.
is open it will have atmospheric pressure which is 14.7 psi absolute or zero, plus the 40 psi making 40 psi. When the engine is under wide-open throttle it will have that reading too because there is no vacuum then either.

F O R   T H E   M E T R I C I Z E D
Say the engine is idling at 50 kpa absolute pressure.
It should have 50 plus 250 = 300 kpa absolute pressure.
is open, it will have atmospheric pressure which is 100 kpa plus 250 kpa or 300 kpa absolute.
Your gauge probably reads atmospheric pressure as ZERO, so it will read 250 kpa. Below 98 C
at idle your gauge would read 200 kpa or 300 kpa absolute.
Fuel injected cars always have a circulating fuel system. That is, the fuel goes in a circle, up to the injectors and back to the tank all the time the engine is running. This prevents vapour lock.
EXCEPT of course when a hot engine is left standing. In this event the problem soon rectifies itself as cold fuel cycles through the system as soon as the key is turned.

You can't beat INTER-JECT experience, the equipment and products. Eventually every one has to have this type of service done for superfine tuning the electronics to the worn engines. There will be no other way out, as to provide real customer satisfaction with INTER-JECT.

K, KE-Jetronic System Diagnostic with INTER-JECT click | Here |
Contamination of the K-Fuel System | Here |
EFI System Diagnostic with INTER-JECT click | Here |
D-Jetronic or MAP sensor click | Here
Top of Page click | Here |

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