124-Fan

Hello all. I have a 1992 300CE-24V( 104.980 engine ) and am having minor problems with it. It sometimes hesitates when taking off. Not very much though. The hesitation goes away if you step a little further and the car shifts into first gear. Seems like when doing low revs and wide throttle opening, the problem is most likely to occur. I strongly suspect loss of spark, but not in any one particular cylinder, though. There are new plugs
( champion C11YCC-the recommended ones), leads, coil, rotor, cap and fuel filter.. the works. I have also noticed slight loss of power when accelerating in fourth gear( the car is 5 speed automatic ), while doing low revs until it shifts into 3rd gear. As soon as it shifted into 3rd gear it behaved normally
( higher revs and less load ). And it never does this when cold. Only sometimes when hot. Not always though. Hmm.?
Any clues..? Anyone experienced something similar..?
Any help or ideas much appreciated.. thanks.

Jer

Could be the injectors and their seals. As they age the mechanical components wear out (needle valves, seats) and you have a loss of power. Look into replacing them. This is especially true when the engine is hot.

124-Fan

You might be right, Jer. Thanks. Although it strikes me a little odd, that one moment itīs perfoming superbly and then all of a sudden it this starts. Then perhaps all is suddenly well again. Sounds a bit electrical... Donīt you think ?

Jer

Not too sure about electrical. The injectors do not have electric solenoids; they operate solely on fuel pressure.

How old is the O2 sensor? It might be sending bogus data to the LH control unit and messing up the mixture.

124-Fan

Yea, I know the injectors arenīt electrical. I was thinking some other electrical failure.
And I was also wondering about the O2 sensor myself. Hooked up an exhaust gas analyzer and all emissions were within limits. CO content was to be excact 0.27%. Given value is max 0.5%
-I believe there is a knock sensor on the intake manifold. If ignition knocking is sensed, it will retard the ignition. Perhaps you could look this up for me if you have any books covering this engine.
Anyhow, I cleaned the terminals on it( I think it was a knock sensor ), they were a bit corroded. It hasnīt done this since. Been driving for a few hours now and allīs well... For now..
Thanks.

Jer

I have the M104 service literature. Let me know what jobs you want.

124-Fan

Well, is there a knock sensor in this injection ?
If so, is it a small black plastic box with a three-pole plug connected to it. Located in front of the fuel distributor under the air filter Attached to the intake manifold. And is there a way of testing it ?
Because Iīd like to know what sensor that is that I cleaned the terminals on. Think itīs a knock sensor..
Thanks.