300E -87 Engine Stalls

[Sweenie]

Hi. I'm desperate!! My engine are stalling when going under 1000 rpm. It doesn't matter if the gears are in P, N, R or D. At first it only happened while i was breaking in low speed, for example at stoplights and such. But now it stalls even when the car is in idle mode. It seems the engine are fighting to keep the rpm up to the normal level, but after a couple of seconds the rpm needle just drops and the car stalls. Sometime when im driving in a high speed, 50mph for example, i can sense a slightly decrease in acceleration, not noticeable on the "rpm-meter" but i can feel it. I believe some people called it "fluxuation"(correct me if i'm wrong). These stalls happens most of the time but there have been a few moments there the engine runs perfect. For example last week when i was going to the local store. I started the car, it runs for 2 seconds and stalls. Then i drove to the store, a 3 minutes ride, parks the car , takes my foot off the gaspedal and WOW! The engine doesn't stall. I let the engine run for a couple of minutes to see if the engine stalls but it doesn't. After i been inside the store, 5 minutes tops, i start the engine and it stalls. Drove home, parks and It..........STALLS!!! I have got used to this and use my left foot to brake because i can never lift my right foot of the gaspedal. I must keep the rpms above 1000 at all times, even when shifting from Drive to Reverse, which give a very rough start. I also fear this takes hard on my breaks, and i get VERY frustrated when it stalls in heavy traffic & parkinglots. I have been to a MB Authorized Repairfirm but all they did was adjusting the CO-value(Air & Fuel mixture). They also told me it could be the airflow-meter. So i replaced it with another one(used though) but the problem is still there. Also very annoying that the car WORKED EVERY TIME i took it to the repairfirm. I could start to change every part of the car until the problem is gone, but i believe it would be cheaper to get it to a junkyard and buy a new car. It's been like this for almost a year now. Hope anyone knows what could be the problem. //Sven-Bertil

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[worleydave]

no message

[Sweenie]

Whats an EOM?

[worleydave]

.

[Level8Drummer]

Once mine was doing something similar. It would hesitate and stall at random times. It turned out to be an electrical problem. The main computer box or something needed to be replaced. Get somebody to test that and see if it's the problem. They might be lazy to do it, but get them to do it anyways. My dealer was like...Well we'll have to take it somewhere where they have the machine to test it. Don't let them just keep replacing parts. Get the computer tested.

Level8Drummer
87 300TE (For Sale)
http://www.hephaestusdesigns.com/mercedes.html

[reitmeid]

My 1986 300E started to do what you are describing. I changed the plugs...they were worn to about .070. and I also changed the distributor cap which was the most worn cap I have ever seen. Since then no further stalling out at return to idle.

[Sweenie]

Well, So far i have replaced the plugs (BERU Ultra-X).
Managed to crush something in Cable nr 5 , so i will have to get a new one. The car runs a little "unsmoothly" now, jerking back & forth. hehe.
However the problem is still there, but i will replace the fuelfilter as well. Had some problems finding it, but i know where it is now.

I replaced the Distributor Cap & rotor a while ago because the engine was misfiring sometimes when starting.

If it still won't work after the fuelfilterchange i will get the "computer" checked.
I don't think that one is gonna be cheap if i have to replace it.

When you say "computer" do you mean the Control Unit for the injection?.
Because AFAIK there seems to be more than one Control Unit...

[Sweenie]

Hi.
I'm just wondering if a leak in the vacuum-system could cause stalling problems?

I'm thinking of checking every vacuum-(hose,tube?, Don't know what they are called).

[MBADVISOR]

Dont just replace parts to replace parts. A good tecnition can diagnose this problem in about an hour. It could be plenty of things. Start with the overvoltage protection relay. If it is an old seimens with a white top, replace it anyway. It is located behind the battery near the fuel computer. It could also be the fuel pump relay. If you jump terminal 7 & 8 & it still stalls then you can look elsewhere. These are the most common culprits.