Please Help with 88 300E
 

My 88 300E with 105000 miles developed a serious problem. A few weeks ago it started to stall a few seconds after I would start the car. If I waited a few minutes, it would run for a few miles and then stall again. Now, I am only able to start it and after about 20 seconds the engine stalls and after few seconds after this, the fuel pumps stop. I changed the catalytic converter before the problem developed and fuel pump relay after the problem persisted (did not help). I really do not know what to do... Is there another relay that could go bad? Are the fuel pumps bad (got two inline) or fuel filter or what else? Any advice would be greatly appreciated...

Have you checked your OVP? It seems alot of people are having trouble with this lately. It is located on the passenger side of the firewall. I have a '87 W124, so I think your '88 should be very similar to mine. Also do a search on OVP and there are plenty of discussions on how to inspect and change one. Good luck.

I don't think this is an OVP problem...check the fuel pressure regulator...this could be the source of your stalling...

Is there power
 

Greetings Peter,

You didn't mention whether you were getting power to the fuel pumps prior to starting and while the engine is running? Can you hear the pumps running to prime the line when you turn on the ignition key? Are the pumps still running after the enine stalls and won't restart? Let's start the troubleshooting their first. If the pumps aren't running, is there power going to the pumps? Put the voltmeter on the pump leads when you turn on the key and see if there is juice making it to the pump. Post your results and we'll go from there.


Charles

Re: Is there power
 

The pumps are priming and running. In fact, there is a delay between the engine stalling and pumps shutting off (they shut off like 10 sec after the engine stalls). I already went under the car to see if the pumps are working and they get power until like 10 sec after the engine stalls. They also get power when the ignition is on. I am not sure what is going on but I see these things that could go out: OVP relay, fuel filter and maybe the fuel pressure regulator but I think that when FPR goes out, it makes the car run real rich (flooding the engine) so I should get some smoke from exhaust... I really have no experience with Mercedes since I usually work on my Porsche, Nissan Pathfinder and 3000GT VR4.... But this is really getting to me...