92 2.6 Runs rough once it warms up!! Help!!! - PeachParts Mercedes-Benz Forum

bajaboat32 · #1 12-07-2003, 07:40 PM

1992 190E 2.6L Starts and runs fine until operating temp is reached. It then idles rough and stumbles as you try to drive it. It never comes out of this no matter how hard you drive it. The car does not get driven very much and sits alot. The problem started without warning. Any ideas on what to look at???? Thank you in advance for you reply.

mike690003 · #2 12-07-2003, 08:24 PM

Check for a burned cap and rotor, and the Supressor cover.

bajaboat32 · #3 12-07-2003, 10:37 PM

WHAT IS THE SUPRESSOR COVER??? WHERE IS IT???
THANKS.

mike690003 · #4 12-11-2003, 05:55 PM

It is a round ceramic plate that goes behind the distributor cap.

380SEGUY · #5 12-12-2003, 12:54 PM

I had the same problem with my 1985 380 SE, it also ran fine until warmed up and then ran terrible.

At cold start the engine temp sensor reads cold and keeps the computer in open loop control where the oxygen sensor is not used to adjust fuel mixture.

As soon as the temp sensor goes above a set temp 160 ?
the computer goes into closed loop operation and uses input from the o2 sensor to constantly adjust the fuel mixture and keep emmissions down.

I used this logic to replace my o2 sensor and the old girl runs great.

For the price it is the best place to start.

Hope this helps

#6 12-14-2003, 11:57 AM

bajaboat32

Any significant drop in your fuel mileage?

Does your car smoke when it starts running rough?

bajaboat32 · #7 12-16-2003, 07:36 PM

Haven't drove the car enough to see if mileage has dropped. It does not smoke when starts running rough.
Thanks for the reply.