92 300E won't start - PeachParts Mercedes-Benz Forum

MBCLASSICS · #1 02-19-2003, 10:16 PM

Hey Guys,
driving home today my 92 300e started dying out on the freeway. It continued sputtering and slowing from 65mph til it stopped and it won't start again. I checked the following: I can hear the fuel pump and gas seems to be getting to the fuel distributor. When I loosened one of the injector lines on top of it fuel runs out. I also checked the fuse on top relay behind the battery, it is okay. I had somebody crank it over and I pulled a plug wire and spark seems to also be fine. I just removed the idle valve and those two lines seem to be connected to the intake. They are hard to see under there to be very sure and it is dark now. Is there an easier access? It seems like it wants to start only when you floor it and crank. Any tips are appreciated. Look forward to being on this site.

Regards,
Steve

drbrandini · #2 02-19-2003, 11:31 PM

There are two fuel pumps on your car, make sure their both working..

drbrandini · #3 02-19-2003, 11:32 PM

Oh, I almost forgot..Welcome and post often..

MBCLASSICS · #4 02-19-2003, 11:57 PM

Thanks,
I will check tommorow to see if both are working.

Regards

MBCLASSICS · #5 02-20-2003, 01:13 AM

BTW,
I also poured some fuel directly in to the intake and it didn't do anything. I would think even if one of the pumps were bad it would at least start for a couple of seconds.

sbourg · #6 02-20-2003, 10:35 AM

I honestly don't know, but I doubt if that would work. The fuel mixture needs to be in a pretty narrow range to work, and likely the gas would just collect and sit in the plenum below the throttle. Fire is a distinct possibility. With gravity-fed designs such as carburetion, this can be a diagnostic, but not with direct port-injection.

Steve

MBCLASSICS · #7 02-20-2003, 04:01 PM

Hey Guys,
just went and tried to start it while cold. It started for about 5 seconds and died out again and won't start. Checked both pumps by feeling them while they were on and they seem good. BTW when it cranks and wants to start it almost has that overadvanced timing feel to the engine. Any ideas?
Regards,
Steve

sbourg · #8 02-21-2003, 10:19 AM

There are lots of things to try, but the easiest is to check for a good spark. Best way is to attach a good used spark plug to one of the wires, with the body of it touching ground (don't hold it!). See what you get while cranking. Also check condition of the inside of distributor cap and rotor.

If that seems ok, you could try limp mode by unplugging the OVP (or removing the fuse(s) on top). If it now runs, plug it back and unplug the EHA to see if lambda control is really haywire, und so weiter...

Steve

MBCLASSICS · #9 02-21-2003, 11:16 AM

I already had sombody crank it while I checked for spark and it seems to be firing good. I also pulled the ovp fuse and tried but it still won't start.
Thanks,
steve

sbourg · #10 02-21-2003, 01:05 PM

You need to check fuel pressure. If it is low, the pressure valves in the injectors won't open, but fuel will still flow out of a disconnected fuel distributor line. Low pressure could be the result of a bad pump or bad pressure regulator, among other things.

Steve

MBCLASSICS · #11 02-23-2003, 08:41 PM

Just wanted to give you guys a update. What was throwing me off was that the car was getting fuel and spark. I eliminated the fuel problem w/ some tests and then went back to the ignition system. I had spark, but figured it wasnt firing at the correct time. I pulled the dist cap off and saw the problem. The part the rotor mounts to on the camshaft had completely sheared off. It was still spinning the rotor and firing spark but not in time. For some reason it looks like the center bolt that mounts it to the cam came loose. Steve ,and everybody thanks for the help and input. I have four classic Benz's and look forward to talking to you guys.

Regards,
Steve