Hi. We have a 1990 300E (3.0) thats seems to randomly stall at different times. Its usually when standing still for a few minutes (bank drive thru) and the when we decide to move she quits.

Sometimes her rpms fall to below 500 and she shakes a bit. Feeding gas, even light amounts, stops this. I personally think it is the fuel pump or pressure, but people seem to tell me its a sensor...any ideas?

Thanks,
Erik

 

I'm having the same problems with the same car.I don't know what to think if I find anything out I'll post it for you. Can you do the same for me. Thanks

 

Sure. We are having it looked at next week, I will post if we figure it out.

Erik

 

Thank you. One more thing can you find out were the blower motor is and the fuse or relay for it?? Thanks very much!!

 

Hi,

My car of same year and probably the same engine (3.0l in-line 6 24-valves) is having similar problem about a month ago. Unlike yours, mine doesn't have the falling rev and the shaking.

I am quite new to Merc but I've heard the OVP relay is notorious of causing problems to the engine control computer. Do you think it a likely culprit of our problem?

 

I don't even know what the OVP relay is!! I'll tell you one thing I was under their today for almost an hour and I can't find anything. These cars have like 100 or so relays and this and that what-cha ma call it's. I'm a little frustrated with it today. But over all Gotta love it! Any input on this topic would be greatly appreciated.

 

The Over Voltage Protection relay is by its name a device protecting the ECU and may as well other circuits from excessive voltage. Quite a no. of users described this guy as notorious to have caused problems, mostly start-up problems. I am not sure if it is the one to blame for my occasional stalling problem.

Someone told me this guy is under the box behind the battery. I have yet to locate it.

 

Call me stupid because I didn't know what OVP stood for but now that you explained it I know. I've seen it before it is behind the battery.

 

The OVP relay does have a service bulletin on it. The problem part number escapes me but I think it was a Seimens part made in Australia. Call a dealer. Anyway the solder joints inside it break. If your any good with a soldering gun just take it appart (pretty easy) and re-solder the bad joint. I did and it work out fine. New part is about $90.
Good luck

 

The faulty OVP is 000 540 52 45
The repalcement is 000 540 67 45

The faults are solder joints and diode breakdown....

The diagnoses is often ABS lamp on

 

Update:

Well, I put on about 2,000 miles on the car (it usually sat for weeks at a time) and it has not stalled once. I think it was that we really never drove the car (10,000 miles in 3 years) and that when she did run for long periods of times she gave up. The car does eat oil like its going out of style...atleast 1qt a week, but other then that its running smoothly. The idle sometimes drops and shakes, but no stalls. I canceled the mechanic appointment because the problem went away, but if it comes back I will post again.

Thanks,
Erik

 

My 1993 280TE also has the same stalling problem - I'm taking it to a specialist next week to get it looked at, but it looks to be the throttle housing may be letting in too much air, this can be cleaned as I have had it done once already - but once on the way out its a nasty big bill.

 

Hello,

I had quit the same problem.

Engine starting only when cold and then it dies when it comes to normal temperature.

The only way to keep it running is to depress the accelerator, when released the engine stops.

I solved the problem changing the distributor rotor and the distributor cap.
They were completely used and burned inside.

Now the engine is running like silk, no more rough idle, no more engine dies, and no more long crank before engine starts.

Hope this writing will help

Regards

 

Sounds exactly like the problem I had on my 260E. Would stall at stoplights. Also if parked for short stop it was impossible to start unless I let it set for a few minutes. Solved completely by replacing the fuel relay module. (located behind battery in engine compartment). A 200$ item but solved the prob
Cheers, Larry

 

hey man,
My car would die ramdomly, have a weak idle. I took it to the dealer, they replaced 2 fuel pumps, ovp relay, idle controller- over 2k. Their work fixed nothing. I was so pissed I sued them and got my money back. Anywho, I fixed the problem by replacing the fuel pump relay. Behind the batt is a rack o fuses The first is the fuel relay, behind it is the kickdown relay. Good luck

the shemdogg

 

If your car is drinking oil like its going out of style and fouling the plugs or running ruff, then you probably need new valve stem seals (very common problem on higher mileage mercedes 300e). Pull the spark plugs out and examine them for oil build and or excessive carbon. Changing valve stem seals on the inline 6 cyl. 12 valve engine is really not that difficult.

Dan

 

Had a similar problem even after replacing the OVP thing and fuel pump relay - lots of conjecture from several Benz gurus, but before taking the their next advice to replace the ignition module (>$1,000), I took it to Mercedes Benz of Tampa where the problem was diagnosed and cured by replacing the timing sensor.

 

are you talking about the relay with the 2 fuses on top or something different

 

Check the date posted. This thread was started and finished over 5 years ago.

Yes, the OVP has 1 or 2 fuses on top of it and is located behind the battery.

 

i have checked the OVP relay but no connections were loose
i have replaced the spark plugs + wires
rotor (was broken)+distridutor cap
fuel filter
air filter
the problem is not solved do you have any other idea
please help me

 

Sure. What's the problem you're having? Describe your symptoms.

You can't really check an OVP for loose connections; you just replace it if you suspect it's bad.

 

Pull out the ECU from the car.If it goes without it,(slower and consuming alot more gas ofcourse) It will be the ECU.I posted this years ago and it helped a few members.
I didn't want to spend $700 for a new one and couldn't find a used one so just took it a part separated the 2 panels and reheated all the soldering joints (appr 200)
Sold the car 2 years later and it is still running with the same ECU.
Good luck!

 

will check and let you know thanks for the advice

 

No problem and good luck.

 

Check your O2 sensor or Temp sensor. Also next would be the EHA valve and the fuel distributor.