Bosch K-Jetronic Fuel Distributor

Please Help:

Due to a bad tank of gas that was 80% water, I am cleaning the entire fuel injection system of my 87' 260e. It uses the Bosch CIS K-Jetronic System. I was doing fine until I realised that there is a gasket between the 2 halfs of the fuel distributor. I cannot find this gasket for sale anywhere! Would it be safe to reuse it, or could I just use some kind of gasket maker to supplement?

wow! i never do that is disassembly the fuel distributor ! the gasket will be a problem. the gas will leaking out .you can try to use the old one .but in care of tie up evenly.regular gasket paper will work just a short times. i will not do it again,
next time to clean that just take the hose before the injector let the gas running throw it to the can and you dont need to disassembly whole thing.......

So, are you saying that the high-temp RTV wouldn't work, or would it? Or are you saying that cutting gasket paper is the only option I have?

the rubber diapghram have certain flexibility assisted by upper (regulating pressure) and lower (system pressure) springs.

opening it will damage the whole unit and will be useless unless:

you know how to calibrate. i do it with the use of gas analyzer with capability of individual cylinder detection...such as BOSCH MOT, or BEAR.
you must know the hydrocarbon emitted by each injector (also CO, CO2, and O2 for any leak).

the difference between every cylinder must not be more than 1.5 parts per milligram. too difficult and time consuming to do. sometimes even an expert cannot do the calibration well.

rtv/ hi temp rtvthink about is you can make a little test is put some of it in the gas ....see it can hold or melt down...
except you use the gas tank fix....
gas can melt down a lot of chemicals,and leaking with the fuel pressure will hardly to hold.....

Well, I put it back together anyways using the old gasket and nothing leaked at all. But now as soon as I start the car up it jumps to about 4,000 RPM's.

Could this high idle be due to the location of the plunger from the distributor? Is all I know is that there were six screws underneath the distributor that I "DID" reinstall correctly to the right ammount of turns which I had made note of during dissasembly.

Could it possibly be an air bypass problem?

even if you will count the turns, it will never be the same again. you open it, and there's nothing much to do inside. it's just an assembly of springs, diapraghm and plate valves.
the control piston causes the high rpm because you haven't adjusted it to basic setting. the idle speed air valve can raise the rpm too. try disconnecting and reconnecting it if there was an effect.

I checked the auxillary air valve, but this had virtually no effect. I thought that the location of the plunger within the unit at idle might be the problem, so I adjusted the screw that holds the plunger into the unit at its bottom. I adjusted the screw so that it was only turned into the unit 1 turn, which allowed the largest degree of plunger travel. When I started the car, the rpms climbed much more slowly to about 3,000 rpms, and after a couple of seconds, shot right back up to 4,000 rpms.

What could be the cause of this problem? I do not believe it is electrical, and the plunger cannot be given any more free travel. I am also fairly sure that there is adequate control pressure at the top of the unit. Might I just need to adjust the 6 hex screws at the bottom of the distributor that control fuel flow to the injectors? If so, which direction should I turn them in order to restrict fuel flow?

Update-

I messed with the screws I described in my last post and this did lower the idle to about 2,000rpms. I then screwed them in another turn and the car now does something very strange. Upon starting, it accellerates to about 2,500rpms, then slowly drops to about 500 rpms, at which point it sounds like its about to die, and then rises back up to 2,000rpms. At this point, when I step on the gas pedal, the car quickly drops rpms and sounds as if it is backfiring, and then dies.

I am curious if this could possibly be an issue with my throttle linkage, as there is a rod connected to the throttle assembly that connects to a cylindrical unit protruding from the side of the engine crankcase. (Fuel pump?) I understand that the orifices within the distributor control the flow of fuel, but I'm sure that the initial fuel pressure also plays a part in how much fuel is going to pass throught the distributor. Any advice?

(Does this sound like it is definately a fuel distributor problem, or could I have screwed something else up? The car idled fine before I started working on it, it just had bad acceleration.)

if you have found that the problem lies on the throttle linkage, then that's another story. i've tried to discourage you from opening that fuel distributor, but not much i can do. i have been through it in my early days, but i am wiser now to take the right steps by eliminating other possibilities first.

familiarity with the system is the first thing, and experience is the other thing... good or bad, i always learn a lot.

your case has now come to the point where you have to rely on your own decission as to what the next step should be done. all i can do now is to give you some quick idea on the system where you could possibly be now.

in your car, the upper chamber is the system pressure. the difference between the upper and lower chamber should be 1.0 bar in order to get a good mixture. your system pressure should be 5.4 bar and the control pressure is 4.4 bar. go get the gauge and check it so that you will know if the electrohydraulic valve is malfunctioning... or was the real problem is the linkage, and you have just messed with the distributor?

if the lower chamber is too low, then this produces a lower pressure difference in the metering slots (you have seen this as the smaller portion of the piston when you open it) and thus a richer mixture.

the electrohydraulic actuator controls the fuel feed to the lower chamber, and thus the lower chamber pressure is necessary in order to alter the lower chamber pressure. the fuel feed can be opened more or less by moving the valve plate. now this is being controlled by the engine control unit. you can adjust it too by removing a cover screw and adjust the allen screw inside, but you have to get the right 4.4 bar of pressure.

is your car in emergency running mode now? if you remove the control unit, does it make any difference?

is the zero position of your sensor plate is okay? i guess you didn't touch this one, and no need for me to tell you how to do it so i can save some typing which i hate most. i always give my advice short and quick because i am a lazy guy.

if there's any particular point where i can just give to you directly, please post it here so that we can share with others. the KE or CIS-E is a very complicated system that i cannot just explain all in here.

do more checking.

Well, I fixed the throttle linkage, and the rpm problem. However, the lower control pressure of the fuel distributor seems to be out of calibration.

Originally, the lower control screws were turned into the unit 9 turns. Now, when I raise the pressure that high, the car will barely start or idle. When I remove the power to the aux. air valve, the car drops in rpms and dies.

When I decrease the pressure of the lower control screws by turning them in only about 6 or 7 turns, the car starts perfectly, idles slightly too high (1100 rpms) and seems to rich. However, the car seems to have lots of power. When I remove the power to the aux. air valve, the car drops to the normal 750 rpms.

My question is whether or not I should continue to try to fine tune the control screws, or if my problem sounds like it is comming from the throttle body mixture screw adjustment or air throttle position. I did actually mess around witht the throttle body mixture screw, but I could not tell any difference, and the spring tension on the plate did not seem to increase or decrease.

(Another bit of info- when I have the lower control screws to the orginal 9 turns they started at, the car is hard to start and when running, backfires when I step on the accelerator. Could I possibly onyl need to adjust the throttle body mixture screw? And do you turn the screw by pushing down and turning, or just turning it period. (Which direction to lean or richen)

My last post was a little long, so I just wanted to sum it up by saying that when I run the mixture rich, it starts fine but uses too much gas. When I run the mixture closer to where it should be, the car does not start without stepping on the gas pedal and backfires when trying to accelerate. All other components have checked out to be fine except the fuel distributor. What are your suggestions as to the nature of the adjustments I should make?

Thank You

you must adjust it by only half each time. it is very sensitive. fine tuning it must be done by 1/8 turn or smaller if possible.

the best way is to observe the difference between system and control pressure.

From my understanding, the system pressure is controlled by the location of the plunger. I currently have the plunger adjusted so that in it's closed state, it is perfectly resting on the pivot of the sensor plate. *Is this wrong and should I screw in the plunger so that it is partially open during it's resting position? *Would this affect acceleration or starting?

the system pressure is controlled by the fuel pressure regulator. it is constant.

the EHA controls the regulating or control pressure by getting some pressure from the system pressure. now i guess you feel your own pressure

the plunger controls the flow of the fuel going to the fuel injectors.
it doesn't change the pressure.
you can feel this whenever you slightly push down the sensor (turn the key on and off several time to build up pressure on the system).

give a little free play on the sensor plate so as not to flood your cylinder with fuel once the engine is off. 4mm would be fine.

please don't confuse the fuction of each component.

just give a difference of 1 bar between sytem and control pressure, and it's done. then you can check other components.

if the engine got too much power and smoke, then it's rich.

I am making definate progress now that I have leaned out the control pressure. In order for the car to start properly with this lower pressure, I am increasing the position of the plunger to give a higher idle. *My question is, how do I know what position the actual throttle plate (air intake) should be open at idel? *If I have it adjusted too constricted (too closed) and keep making up for it by screwing in the plunger, will this really matter? *Should I keep adjusting the plunger for correct idle and starting, or should I try opening up the throttle air plate more?

I am making definate progress now that I have leaned out the control pressure. In order for the car to start properly with this lower pressure, I am increasing the position of the plunger to give a higher idle. *My question is, how do I know what position the actual throttle plate (air intake) should be open at idel? *If I have it adjusted too constricted (too closed) and keep making up for it by screwing in the plunger, will this really matter? *Should I keep adjusting the plunger for correct idle and starting, or should I try opening up the throttle air plate more?

there is an adjustment screw beside the fuel distributor. originnally there is metal cap on it, just pry it out.

adjust from there. this sets the base for the sensor plate position.

the sensor plate is already in basic position if you haven't moved that adjusting screw.

I have 3 more questions:

1) can I make the adjustments while the engine is running, or does it have to be off?

2) will adjusting the sensor plate affect idle and starting?

3) should I set the plunger to the lowest level and adjust the sensor plate in order to obtain correct idle and starting?

YES. the engine should be running while doing the adjustment. adjust it until the engine stops shaking and you can hear the business hum that says... this is it.

it will affect if you will adjust it too much, which will flood the cylinders. while turning on the ign on and off several times, you will feel the plate resting on that plunger. you must give a little bit of free play. too lean will be hard starting, which means you have to assist the engine by pushing down that plate in order to get the injectors working.

which plunger, the control piston?
there must be still a visible old mark if you haven't count the turns before. i never had any problem adjusting it. maybe about 4 turns before its tight is fine.
yes. do the plunger first. the sensor plate is your fine tuning.

After adjusting the plunger to 4 turns from tight as you suggested, the starting problem is fixed. In fact, the car runs much better and does not shake as violently during idle.

However, I have 3 more questions:

1) The car idles Ok but slightly high initially when cold. Upon warming up, the car's idle steadily decreases until it dies. Is this a symptom of being too rich, or is this due to the zeroed position of the sensor plate?

2) I tried adjusting the screw next to the distributor (for the sensor plate) while the car was running and noticed no effect. Could this screw be broken, because I can keep screwing it in one direction and it never comes to a stop?

3) Upon checking the spark plugs, I notice they are still slightly black and glistening from gasoline, indicating to me that the car is still running rich and flooding. (gasoline) I previously discovered that the spark plugs gap was too high and have decreased the gap. Could improper gap of the spark plugs be to blame for misfiring during acceleration? Since I have now adjusted their gap, should I try to lean out the lower control pressure screws, which previously I could lean no further without the car backfiring upon quick acceleration.

it is normal for the idle speed to be high during warmup...about 1200 rpm. this is because the valve plate inside the electrohydraulic actuator is closed. it is thermally controlled. to keep the idle speed from falling down, adjust that screw. tighten it down.

maybe you didn't turn the screw at all. try using the allen wrench of 4mm. tighten it (clockwise). the you will find it's changing the idle speed. set the idle speed according to that small sticker on the front beam when to hood is open.

the gap should be 0.8mm maximum is 1mm. yes, it can cause backfire but on exhaust. your backfire is from the intake, therefore it is a fuel starvation. your EHA is still faulty because it cannot open in time and cannot cope up with the pressure.

I am still not familiar with what the EHA is. Is this the black cube made of plastic protruding from the side of the fuel distributor with wires connected to it? If so, how do I access this adjustment screw and how should I adjust it? To the correct idle when warm or when cold?

yes it is that black box.

i suggest that you don't adjust that one. it controls the pressure.

there's two screws, top screw as sealing, and lower screw for adjustment.

This thread makes me want to completely disassemble my refrigerator.