Over revving at start
 

My'95 C280 revs up to over 2K rpm when starting cold. It immediately idles down to normal, but it makes a lot of noise and makes people look when I start it in public.

The check engine light has been on for several months after several attempts by various garages to fix the problem. The car has had O2 sensors, MAF, vacuum box, head gasket- you name it and it still has the CEL on. The over-revving phenomena is fairly new.

Any thoughts on the revving problem? If the car is warm, it starts without the over rev problem.

Thanks in advance.

BigLar

Over revving
 

I guess the over-revving has stumped the experts- that's scaring me.

BigLar

No, you didn't stump anybody,......just scared them. :D
Why is your CEL on ?
Have you had the codes read lately?
Please report back with code #'s. ;)

My 380 revs up to about 1800-2000 when I start it, then goes back down. I know this cannot be good for the engine. One time it did it and it made a dreadful knocking noise. I made a post about this awhile back, asking if this was normal, but oddly, there were NO replies. I guess no one pays any attention to that. :confused: :rolleyes:

These vehicles have an engine loom wiring problem...they come apart and short out. New loom is around $1200.00.

Check your OVPR for date and function. There's a (#30 position) fuse that powers the OVPR to pin #4.

Have had issue with throttle kick down relay shorting out once..

Check all vac' hoses as they deteriorate and perforate allowing false air.
Also need to read off the codes and reset to allow adaption to complete.

dk


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I had same problem
 

I had the same problem, and my car on a cold start would roar to near 2500 RPM. You'll find my thread, its fairly recent. On my car it did this, and then one day the gauges began to move back and forth on their own during a start attept and that was it, the car was dead yet fully powered. My CEL was on also at the time. Since I got a new starter put in, car's been perfectly fine....check my old thread from couple weeks ago, everything in there.

I am assuming you are referring to the 95' C280 having an issue with the wiring looms? I am assuming since I have never heard of a wiring issue with the W126 of any year.

I guess my problem is different, if it is indeed a problem. No one seems to reply with their startup RPMS. I have no idea if my 1800 rpm is normal or not. It remains a mystery. :rolleyes:

I was refering to BIGLAR's post on his startup flair.
Your correct...126's did not have a wiring loom problem...untill the rat's get in and eat it :D

However...since the German goverment in the 90's required manufacturers to produce bio-degradable products, a lot of German origin vehicles are/have wiring insulation problems.:rolleyes:

Usually the engine will run at 1100 rpm at cold start up. If it is higher...a lot higher....there's a problem.

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Over revving- wiring loom
 

Hello All,

Thanks for the feed-back, makes me feel loved!

My C280 had a new wiring harness a few years back, under the "good will" policy for good customers (former owner).

BigLar