600SL starting problems

[Johnny600SL]

Hello I have a 1993 600SL with an intermittent starting problem

I parked it, 2 minutes later tried to start it, and it would turn over but not start it has fuel to the rail, spark and compression, months before this I had the same problem, stopped by my friends house for a minute, tried to start it, it would not start same problem. Had it towed to a Local Mercedes mechanic, next day it started right up, so I came down to the shop, test drove it parked it back at the shop, tried to start it a minute later, same problem, so the mechanic checks the fuel pressure, it has 4 bar, it turns over it sparks, and won't start, another thing right before it does this, when I try to start it, it first tries to start, fires a few times, after that, nothing, well, the 2nd day in the shop, it starts up, runs, drives normally, test drove it 5 or 6 times to make sure, and nothing, strange thing is the mechanic didn't do anything to it, just for good measure he replaces the fuel pump relays before I take it home, anyway months later, Now I have the same problem once again.

I have a feling it will start tomorrow. but I'd like to solve this problem, can anyone help me?

By the way it has no security system.

Thanks,
Jonathan P

[bill streep]

Sounds like an OVP relay. But, could be a wiring harness. Don't know if the V-12 has either of these very common problems.

[flyfishingbear]

Sounds like the exact same thing I have had with my 600SL. They first said I had a short in the injector harness, that was nearly $5k with labor at MBZ dealer. That fixed it for a while, then it did the same thing, but instead of intermittent it was all the time, they then said it needed two new ECU units, they gave me a "discounted" price since I have had them do all the work on all three of my MBZ's another SL, and an ML. The discounted cost was $6k. It cured the problem for a few months and then it has started again. I couldn't get it to start at the golf course after playing 18 holes, same symptoms, spark, gas, no start, I had to get a flatbed truck to move it since I run low profile AMG rims with Michlein Pilot Sport (the good ones) with the sport package. They were not able to come until the next morning, so when I got there to meet them I thought I'd check it while I waited- and of course it started right up. It still makes me nervous, whenever it doesn't kick right off the first try. I changed the plugs out to the Bosch double tip platiniums, but I worry that there is something in the electronics thats doing this. When I took automotive classes we always said that if you had a spark, gas and compression, and they occured at the right time, the car had to start. Need to tell that to Mercedes because the 600s seem to defy that rule. I am seriously looking at tarding it in and getting a V8 SL or even resorting to a vette or other car that actually follows the rules. I just can't think of another car I'd like more, other stuff seems like a step down. I thought about a 911 Porsche, but I want a convertable that can handle two golf bags or luggage for my wife and I for a weekend at Pebble Beach, most of the others don't fit the bill. The SLK, boxster, 911, Lexus, Honda (Acura) NSX all don't have any room for a briefcase much less real luggage. After 30+ years of SLs, it's hard to imagine my garage without one. But you'd think a car at this level would perform at the level it's priced.

[Johnny600SL]

Thanks very much for the replies I think I found out what the problem was, there was a drain plugged near the fuse box, the whole area around the fuse box was filled with water, I siphoned about 2 gallons or more out of it, the next day after it started up and drove home, haven't had the problem sense my guess is it shorted out the injection system.
It had been raining the whole week and the first time it happened I had just washed my car so I think this was the problem. or at least I hope.