Over Rev - Idle problem

[Andymadman]

Hi, I have an 88 124 230E 8v. When the engine is running it toggles between revving at 8-900 rpm and 2500 rpm (it is nice in traffic jams.) The reving is caused by the idle speed valves signal (change in duty cycle)from the ECU. The ECU has been swapped and the problem continues. The only other thing it can be is a sensor! anyone seen this before or will it be a case of change a sensor at a time until it stops?  

 

[David Halsey]

Over Rev

Try the air slide valve, you may find that it is blocked and sticky with oil and the such.
carb cleaner sometimes brings them back to life, otherewise its new one time.
This is only a hunch, maybe you sahould get a specialist to check the vehicle.

 

[Andy]

Over Rev

Hi Andy,

I echo David's sentiments. Get a specialist to look at it. Its very rare the KE control unit goes faulty on a 230e, I have had a few on 300e. You need to get the ke system checked, to isolate the fault. If you look through the forum this question has cropped a fare few times.

If I can be of any help. Then contact me at www.mercedesservicing.com

Regards
Andy Gayle

 

[Andymadman]

Over Rev

Hi again, Will see what my local dealer says, and get back to you.