SL Wont start

I have a problem my mechanic cannot figure out. Mt car is a 1995 sl 500 with 48k miles. If I leave my car sitting for about 1 month it starts fine but if I drive for a while then shut it off it will not start. It backfires and chokes but will not start. If I leave it for about 30min it will then start and drive problem free for the rest of the day. This is driving me crazy. Please help. Have replaced: spark plugs, main wiring harness because it had rotted out ($500). Any ideas would be be appreciated.

I think you have some problems with your electronic starter. My 300E and S500 Coupe also has this problem. It's mainly due because it's too old. It's quite expensive though, an original Merc one cost about US$2,600, while a Bosch one cost about US$1,800.
I hope this helps.

Do you have a more accurate name for part or part number?

I'm sorry, my S500 Coupe is being painted at the moment, the old spoilt electronic starter is in the boot. But I think your mechanic should know what the electronic starter is.

What exactly does this starter do? When you initially wrote about the starter I immediately thought of the one to turn over the engine.

Not that one.
I'm not very sure what it does, but that pariticular part is located in the bonet. It's about as big as a CD case. I'm sorry for not being able to remember what is the proper name for that particular part. I'll post it here as soon as I get my car back.

When you replaced this part did it solved your problem?

check number 8 fuse under bonnet.also if fitted fuse in middle of engine bay near w/screen.

I got it fixed about two months ago.

Did this replaced part fix your problem and was this the same exact problem as mine? Can you give an exact description of your problem? That kind of money for a fix is very high if it doesnt actually resolve my problem.

My engine went dead quite often. Not exactly like yours, but it has something to do with the part I mentioned. I too, when the engine's warmed up enough, it won't cause any problems. But once, I just went out and was going to climb a slope, the engine (S500 Coupe) suddenly went dead.
You could ask your mechanic to check that part to see whether it has any problems.

Okay I will ask him about it. Electronic starter, he should be aware of what I am speaking about, correct?

Erm... I think so...
lol...
Good luck!

How does a wiring harness rot out? I just sold my 1974 450SL with the original harness still intact. It sounds to me (if the wiring was quality and installed correctly), that you are suffering from percolation in the fuel lines. Usually occurs in hot humid areas or with poor quality fuel. The fuel lines heat up and the fuel lines develop vapor lock. Crank it a few times and the vapor locks cause the backfire you experience. The engine will start but lug until the fuel pressure clears the vapor lock. It was a common problem when I lived in Georgia on hot humid days after driving awhile then leaving the car and trying to start it up after a few hours. You should also check your fuel lines and make sure they are not in contact with any heat source and that you have no high spots or tight bends in the line routing where air can be trapped. Sometimes the fuel pump can't easily overcome trapped air.

The rot was attributed to Chrysler using inferior parts since they merged with Mercedes. They used to replace the part but they were losing too much money and stopped.
As far as the vapor lock is it possible to remedy this problem if none of your checks are seen?

Have you had the fuel filter replaced recently? It's probably due if you haven't. Has any fuel line or injector hose been replaced? Once those lines have been checked for heat and kink free placement then the fuel pump delivery pressure should be checked. Did your mechanic check for a leaking injector? After driving, a worn injector or injectors will slowly leak fuel into the cylinder which could cause a hard start and backfire. Are you using a genuine MB mechanic? Your symptoms are not difficult to evaluate with the proper equipment.

Tawom,
When the mechanic can't solve it, I try QuikMechanic at:
http://www.ineed1.com/quikmechanic.html

I used them before, and they helped alot. It's alot cheaper than going to the shop and they don't fix it, but charge me $68 or more per hour. It's just $1 anyway, so you can't go wrong.

Chutch





I have a problem my mechanic cannot figure out. Mt car is a 1995 sl 500 with 48k miles. If I leave my car sitting for about 1 month it starts fine but if I drive for a while then shut it off it will not start. It backfires and chokes but will not start. If I leave it for about 30min it will then start and drive problem free for the rest of the day. This is driving me crazy. Please help. Have replaced: spark plugs, main wiring harness because it had rotted out ($500). Any ideas would be be appreciated.

Dear MB owner, Two years ago I started having the same problems. If the dealer had it their way they would removed my fuel tank and "cleaned" it out. Also added a new starter, plugs, and distributor cap. I didn't get this all done, especially at the expensive dealer. Not wanting to spend all that money I saw an MB owner sitting in his car and decided to ask him if he ever had the same thing happen. He thought for a minute and said yes. He said a few hundred dollars later the problem was still there. Soon thereafter he found out that some gas stations in Utah have water in their gas! How it got there who knows. But at the time I was using Chevron. I switched to 7-11 and bought a bottle of water remover at the cost of $1.00!. All my problems have sinced disappered. After I called back to the dealer and others I had spoken to and they said," Oh yeah, MB's can be a little sensitive to water in the gas, more so than other cars." Funny how they never mentioned to try the $1.00 fix first. Everyone was so eagar to point out how expensive this was going to be that no one bothered to try the simplier thing first. I hope this helps.