1989 300e starting problem - PeachParts Mercedes-Benz Forum

gbvette98 · #1 02-28-2007, 03:01 PM

1989 300e (109k miles) won't start. If I pull the fuel pump relay it will start and run until it runs out of gas ( about 5-10 seconds) I then put the fuel pump relay back in, and it wont start, after a few cranks I pull the relay out and it starts again until it runs out of gas again (5-10 seconds)

Is this a bad relay? I have second one I got from a junk yard from a 300e with 150k miles and it does the exact same thing?

Any ideas?

Also, what is the other relay behind the fuel pump relay for?

zcc · #2 02-28-2007, 04:05 PM

Do you have enough gas in the tank???

gbvette98 · #3 02-28-2007, 05:41 PM

yes, I do.

gbvette98 · #4 03-01-2007, 11:21 AM

I went through all the steps in fuel pump relay schematics troubleshooter and it all tests out good. I had already metered the OVP on the bench but just checked the socket to make sure it's getting juice, which it is and it is clicking when you turn the key to the on position, so I believe the OVP should be ruled out.

When I bypassed the fuel pump relay, the fuel pump does turn on constantly ( doesn't cut out) but she doesn't start either but if I remove the 12v feed she starts until it runs out of gas in the cyclinders (5-10 seconds), back to square one

. What is that telling me?

I appreciate your time as I'm pulling my hair out over here

david s poole · #5 03-01-2007, 12:17 PM

maybe the piston is stuck up in the fuel distributor and the engine gets too much fuel with the pump running.try jumping the relay and tapping on the top of the fuel distributor.