Checking the fuel distributor of the Bosch CIS (K-Jetronic)

[TradingCarz]

@SBT300 i have an 83 Scirocco with this type of injection system...any tips you have for cleaning the system and removing it?

[SBT300]

@TradingCarz Do not take the fuel distributor itself apart. You can use standard carb cleaner.Other than that? Be careful and do not break anything ;-)

[TradingCarz]

@SBT300 i recently just took out the injectors and gave them a good cleaning, now it runs alot better!

[RzXVeRSaTiiLe]

Hi i have a 84 500 sec very clean but it has been sitting for a while and now i've gradually started driving it daily for maybe an hour a day. it drives smooth and shifts smooth but the only thing it has a little hesitation at the idle like it will be calm then kick every once and a while? i want to rebuild my fuel distributor myself any suggestions?

[SBT300]

@RzXVeRSaTiiLe Don't take the fuel distributor apart. Afaik they have no gasket as the metal parts are mated together with the thin stainless steel plate of the distribution valves in such way in the plant, that they are tight by themselves. You can't do that yourself I was told, and I never tried...

I would treat the distributor with lots of carb cleaner, and mount new injection valves. Also check all the pressures to be sure it's not simply a pressure issue.

[RzXVeRSaTiiLe]

@SBT300 thank you very much and i will.

[mikethebrick]

hi i have a 76 350se been standing since 1995 put a new fuel put on it but can only get it running on 4 cylinders the off side the near side wont fire I think its some to do with a little valve at the front of the engine any ideas ?? thanks mike

[SBT300]

@mikethebrick Hi Mike, all devices on the K-Jet have the same effect on all cylinders - except the fuel distributor and the injection valves. So if your engine is mechanically ok, and the ignition system is ok; and the engine is not running on all the cylinders, it's the fuel distributor or the injection valves. You can disconnect the lines going from the distributor to the valves, bridge the fuel pump so that is runs continuously and then push down the air flow meter plate.

[SBT300]

@mikethebrick If you see visible differences in the fuel quantity coming out of the 8 ports, your distributor is not working correctly. You can try to clean it as I described below. If there seems to be the same quantity coming out of each port, remove the injection valves from the engine, connect them to the lines (hanging in the air) and see if they are all injecting. If not, putting them into a supersonic cleaner withpetrol and inj sys cleaner can do the trick.

[SBT300]

@mikethebrick If they are all injecting, and still your engine is not running on all cylinders, there is a problem with the ignition timing or something mechanical like no compression, engine valves...

[fbturbo930]

What's your take the problem -

Car was stading for about 2 1/2 years, have occasionally crank n turn over the engine. Got spark.

1- car trying really hard to start, once started it only stay running for maybe 10 sec's. I press the air flow sensor I can hear the fuel dispensing in the injectors. Check WUR cold 1.5 bar fuel pressure. Not able to check others as engine won't stay idle n die off ????

[SBT300]

You can short cut the fuel pump and let it run without the engine running, so that you can measure all the pressures. Can you keep the engine running with the accelerator pedal? If not have someone else push a little bit on the air flow sensor so that it get's enough fuel ti run. Sounds like the injection system has stale gas in it and will probably run fine after some running.

[SBT300]

If all that does not help you can remove the fuel distributor from the housing and remove VERY carfully the control piston, Then clean everything with acetone. DO NOT take apart the fuel distributor itself, only remove the piston from below. Also you can clean the injector nozzles with a ultrasonic cleaner.

[SBT300]

If all that also doesn't help it probably starts to get expensive, but send me a

message, not all is lost yet! ;-)

[fbturbo930]

@SBT300

OK the weather is getting warm and i am about to tackle the distributor soon, I will let you know outcome after I clean the distributor piston.

Question - Wud spraying some carb cleaner thru the main fuel inlet works ? I sure don't know how to get to the piston w/o disassemble the whole thing

[SBT300]

Yep, carb cleaner will do no harm.

[zech007]

what did you do to make it flow the fuel?

[SBT300]

I connected the fuel pump and then manually pushed the control piston (which is normally connected to the air flow meter) up. If the valves inside the distributor block are not stuck, fuel comes out.