m104 3.0 KE-Jetronic Sometimes won't start, smoke inside intake manifold
 

Hi.

I have quite a big problem with my w124 m104 3.0 with ke-jetronic. Usually engine works fine, start correctly, idle are alright and everything run as it should. But..

Sometimes, when I turn off the engine and I am trying to start it again after few minutes there is some problem. Engine won't start but when I relase the key it trying to catch. If it happen there is a lot of smoke inside the ke jetronic distributor and also whole intake manifold is full of smoke.

I think that there may by some problem with ignition but I don't have idea where I should start searching. I replaced CPS, distributor cap doesn't look bad, cables too.

Do you have some advice? :)

Mine had a problem where it misfired for a minute after a hot start. This was after being left for 15-45 minutes. The answer was to replace all the fuel injector valves.

Why?

Because the valves were failing to close completely and leaking fuel into the inlet when the hot engine was resting. The mixture was then very rich when restarted and took a few minutes to get back to normal when statted.

I also put new injector valve guides and seal in to make sure there are no vacuum leaks.

RayH

I have just replaced 6 injector for brand new, because they were leaking - as you said. But problem still didn't resolve.

I discovered another thing. If I press quickly throttle pedal to the metal, engine is starting to choking between 1-2k rpm. But if I hold rpms at high level ( more that 4k) for few second and then I press throttle quickly engine works great so maybe there is some problem with catalysts or exhaust system at all?

What is the history of the car? Were the symptoms sudden or is this a new purchase?

Pull the cold start injector off the manifold and look for leaks from the tip ( I'm pretty sure it has one ) . Also probe the electrical connector, the cold start is only used something like sub 40*F and only while cranking. This system should have a thermo time switch controlling this action, if the cranking event occurs for too long, the cold start injector is supposed to shut off.

I've got this car few years. Symptoms were sudden.

I will check cold start injector tomorrow because now I don't have much free time but I made simple test. I have blinded by screw fuel hose which is going to this injector and it didn't change anything so probably that is not a problem (but I will check it tommorow). Now car don't want to start at all (it's cold). When I relase the key it starting to waking up and a lot of smoke is going out of throttle body... Probably tommorow it will start without any problem... :/