Hello! I'm the new and proud owner (and new here!) of a 1990 300SL I bought the car in February out of California, picked it up and drove it to Minnesota without a hitch (except an extended 8 day stay in Phoenix, got to take the top off and cruise).

All of a sudden a reoccurring problem is happening. Here is my situation: I left the house a few days ago and the car sputtered and died. I started it up and left the driveway, made it to the corner and the same problem. It sat for two weeks and I thought maybe I might have something in the fuel system and I'd just blow it out. I drove for two miles, no problem. I stopped for a stop sign, started to take off and it sputtered and died. I could get it restarted about a half dozen times and would die each time I stepped on the accelerator pedal. I let it sit for about an hour, turned it over and it would start briefly and die again. When it did start, it would cut out at about 2000-3000 rpms in neutral. Finally it started to rev normally and I drove it home. I started and drove it twice since then, NO PROBLEM. Drove to the store tonight, (about two miles) and the same problem. Identical scenario. All of a sudden it started and is fine again. Seems to be a gremlin somewhere! Any help would be greatly appreciated! Thanks guys!

 

it maybe a fuel pump. maybe the coil. check for vacuum leaks, check your distributor cap, rotor and plugs. then try replacing the red top high voltage relay in your passenger side module compartment, a fairly inexpensive try.

 

Thanks Brooking! Now it just turns over without firing!

 

try cranking the car. then pull a spark plug and see if it's wet with gas. you could put the wire on the plug out of the engine and see it it snaps or use a spark tester while cranking. don't hold on to it. keep it away from metal parts. look at all the basics first, hoses, wiring, connectors, etc. might check the contacts on the MAS module, where that high voltage relay is. I had a fuel pump go out on me with similar symptoms and that relay is an intermittent pain too. Look at your service records if available to see what's been replaced and when. these cars can be a challenge. still, after a ton of time and money I still think she's worth it. find out if it's spark or fuel.

 

Brookings, Once again, thanks for getting back to me! I'll start at the beginning and work my way through and I'll post my results to you. I agree with you that there will be a learning curve for me but I can tell you this much: when the car left me stranded, I walked home without so much as a utterance of a bad word, whereas had it been any other car I might have been tempted to burn it to the ground. The love affair is intact!

 

I let it sit for two days, went out to it and she started up immediately, ran for 20 seconds, killed and then would only crank over. Seemed like it wanted to start but couldn't. HELP please!!!!

 

Since it will start after sitting, run for 10-12 seconds then die, crank fine with no restart, mean anything significant? I'm kinda lost!!!

 

get a spark detector and eliminate that as the problem. they are very inexpensive. your car has self diagnostic capability from the diagnostic ports mounted on the firewall just behind the passenger side strut mount. the MAS module has the fuel pump relay built in and it stores error codes, the EZL module does not, it has to be tested while engine is running. most all other modules have error code storage capability. you can get an impulse counter or short ports 1 and 14 for 2 to 4 seconds with key on and if there is only one flash though your top switch there are no problems in the MAS system. you really should get a subsription to alldata.com, it's a big help and will be in the future.

 

Thanks again for your help Brookings! I order a spark detector and filter and will start there! Do you think Alldata has more available knowledge than this forum?

 

other things to consider would be the cam or crank position sensors and the ezl module mounted on the drivers side fender well. these part failures are rare but possible. is there a check engine light on?