Idle Acceleration Stall W124
 

Hi All!

At my wits end. 1991 300CE with 111K. Gone over vehicle thoroughly replacing worn or suspect parts.............

Here is the situation:

Rough starting warm worse than cold.

Idles around 750 rpm with A/C on or off.

Main concern is stall condition from stop with A/C on. A/C cools fine.

The following items have been replaced in the last 5 months:

Plugs, rotor & cap
EHA valve
Cold Start Valve
OVP
Fan Clutch
All thermo sensors
O2 sensor
Fuel Filter

Any help would be greatly appreciated.

I have not checked the idle control valve yet.....but....how do you adjust the idle? I have adjusted the idle mixture to no avail. I cannot get the same readings with the a/c on as with the a/c off.

HELP!

John

jgmccahon,

Looking at all items you replaced, u missed the fuel injectors. Try those before trying more expensive parts. I wish I would of done that with my car. I went and replaced the fuel distributor ($600) before finding out that it was my injectors that were bad. Injectors only cost $25/each.



Hope this helps.


vu

pour techron and drive somewhere far, and push
it really hard!!

What type of plugs did you use?
 

PO had plats in our 560 which seemed rough to me but i had nothing to compare it to. After reading several plat vs Bosch copper threads here, changed plugs and car smoothed out a ton, especially at warm idle. Fuel mileage improved by about 1 mpg, which translated to about a 6 to 8 week payback.

Plugs......
 

Went through the platinum routine.......back to standard.

Problem exists only upon start-up or from full stop.

Runs great at any speed and idles fine.

Start-up problem gets worse when warm as time from shut-off increases, ie., 5 minutes OK but 45 minutes bad and 1 1/2 hours terrible.

Acceleration from full stop - engine stalls when punched (in other words no left turns unless there isn't a car for miles!)