300 Sel Cuts Off !

[very tired]

My 89 300 SEL sat for 2 months. It was hard to start. Put in injector cleaner and new gas. No problems for a couple runs now the GHOST IS BACK !

I started it. Went 2 blocks and cut off about 10 minutes. VERY HARD to restart. Drove 2 blocks and it just cut off! Restarted and cut back off after about i block.

I live in a rural area and trying to figure things out before I have to tow it 75 miles for service.

Very Tired

[Moneypit SEL]

I had a similar problem. It would sometimes stall while warming up, but would restart before I had time to check anything. I eventually found and repaired a circuit board trace in my fuel pump relay, and it hasn't stalled since.

Since your car takes longer to restart, a simple test would be to remove the fuel pump relay and jumper pins 7 & 8 to power the fuel pump directly. If it then starts and runs, you've found the problem.

[bru123]

i had similar problem with mine i kind of fixed by removing the
fuel distributor filted from the return line that was clogged

[autozen]

Intermittent is a word mechanics dread. You have several possibilities for the problem. Moneypit pointed out how to check one of them. Three other possibilities come to mind: failing fuel pumps, failing over voltage protection relay, or failing EZL unit. I've seen them all. Next time it craps out, you can unplug the ECU just to get down to basic CIS. The car will run without the ECU. Good luck.

[Mike Murrell]

I had a very similar issue with a '91 300-SEL.

Fortunately for you, the 88 & 89 models have a non-integrated fuel pump relay which may be repaired as mentioned above or replaced for not too much. The 90-91 models have about 6 or 7 circuits integrated in a MAS unit to include the fuel pump relay and it's about $450.00. You're lucky.

When I got the car to start and run successfully after jumpering pins 1 & 2 in the MAS, I replaced the FPR and the problem went away. There may be a similar approach available for the FPR in your car. I believe it's near your battery.

About a yr. later, the car would stall after heat soak(car fully warmed up and shut off-then restarted 5-10 mins. or so later). The vehicle would die pulling away after restart. Removed OVP, did the shake test - I heard rattling inside - replaced - no more stall after heat soak.

I'd bet a buck it's your FPR or OVP or a combination. Dig around the SEARCH facility for ways to diagnose the FPR in your vehicle and remove/shake your OVP. If you hear rattling replace. Just becuase it doesn't rattle when shaken does not means it's well. I believe the ABS light will also come on if the OVP is bad. Again, the SEARCH function will keep you busy for days reading about the OVP.