83 380SEL dies suddenly no pattern?
 

1983 380SEL
108k miles
Have only driven it for about a month / owned it for aprox 2 months
Cincinnati, OH Weather has been rainy and 38 - 60 range weather

The car runs smooth
Over the last 5 days it has suddenly died on me aprox 4 times.

First time I was going up slight incline on fairly busy street about 35 mph at night, lights on. Died, started right back up,, 45 seconds it died again, started right back up. Drove another 30 min, no problem.

Second time,,, don't remember the details, but it did start right back up, This was about 2 days after the first.

Third time, going down slight incline at night, aprox 45 mph, lights and heat on, probably had wipers on slow, died and would not start. Engine turns over fine just does not even hit. After about 5 minutes it started up and ran fine. Drove it for another hour with no problems.

4th time, 2:30 pm, lights off, no heat, neighborhood street, aprox 20 mph, slight down incline, ded and would not start. Had to take care of some business and was not able to try it for aprox 50 minutes. Started fine and drove another 20 min. no problems.

Each time it gave no warning, just died like I turned the key off. The lights and gauges stayed on, just lost the engine.

About 3 weeks ago I changed the rotor and distributor cap, old one was looking corroded. Installed Bosh on both.

The only pattern I can see is that each time it seems to take longer to re-start and it seems to happen more frequently. When it does start it runs perfectly like nothing happened.

If it was an old Ford I would probably replace the coil. On this one I don't know. Hate to start replacing parts wihen I don't know what I'm doing.

Any help is appreciated.

Thansk!
51

Check OVP relay and Fuel Pump Relay.

Might also be the crank position sensor.

Its possible you may have gotten a bad distributor rotor....I did on my 300E, it was a Bosch that tested WAY out of resistance spec (1600ohm vs. 1000 +-100 that it should be) after only a few months. I bought a NAPA replacement that tested perfectly at 1000.5 ohm....and now it has run perfect ever since. (over 3 months now)

Believe it is the fuel pump or the relay. Pump is not coming on now. Didn't have time to narrow it down but I am sure it is not coming on.

the fuel pump relay can be repaired. I had this problem and re soldering the joints fixed it . The symptoms just as you described.
mak
300se

Fuel pump is OK. I hooked 12 volts to it and it runs fine. How do I test the relay? I know the 10a fuse is good and I can see the diagram on the side of the relay but I can't say I really understand it. I do have a good multimeter and can follow instructions.
Thanks!
51

not the fuel pump relay
 

OK, I found another fuel pump relay at a scrap yard, installed it and it will not start. I can put 12 v to the fuel pump and it will start. Any other fuses or relays to check? Any other suggestions?
Thanks!
51

My old 1985 380SE would stall. Took it to the shop... MB tech said i was bad injectors.

OK, I got it!
It was the fuel pump relay, and I was able to re-solder 1 post in there and fix it.
The relay I previously replaced was the wrong one.
Thanks!
51