500sl hard start after 4hrs - PeachParts Mercedes-Benz Forum

Marlie's · #1 08-22-2006, 04:55 PM

Has anyone experienced a problem where their 92 500sl starts great at first start of day. But after it sits for at about 4hrs it is very hard to start. When it starts, it has a real rough idle for a few seconds. Any suggestions or assistance is greatly appreciated.

Roncallo · #2 08-22-2006, 09:25 PM

Quote:

Originally Posted by Marlie's

Has anyone experienced a problem where their 92 500sl starts great at first start of day. But after it sits for at about 4hrs it is very hard to start. When it starts, it has a real rough idle for a few seconds. Any suggestions or assistance is greatly appreciated.

I havent experianced it but I would suspect leaking fuel injectors or cold start injector. If the injectors leak the accumumulator will be fully purged befor the next start, plus you will have wet plugs. If this is the problem I would also change oil & filter

John Roncallo

Marlie's · #3 08-23-2006, 03:11 PM

RONCALLO, thanks so much for the info ! Sounds like a great place to start.

Breathing a sigh of relief,
Marlie's

Gary Ganaway · #4 08-23-2006, 06:55 PM

not sure on your model but on my 85 380SE it was the fuel accumulator. Not to bad to replace, next to the fuel filter in the rear,and naot to expensive, maybe $40 or so.

Marlie's · #5 08-25-2006, 04:01 PM

Thank you for the feedback. My '92 500SL has only 53k miles on it and I love it. I am going to purchase the fuel accumulator and perform the 'B' service to see if that will fix the problem.

LeaUK · #6 08-27-2006, 10:49 AM

On my '93 (LH engine) this problem signals that I need to clean both the distributor caps. These cars eat distributors! After 6-9 months both my caps show serious carbon tracking on this inside. Once cleaned the problem goes away.

Clean/replace your caps first just in case.

Lea

nt-j · #7 08-30-2006, 11:07 AM

I had the same problem, try a good quality dose of injector cleaner.
It cured mine and helped the performance. Try FORTE Advanced Gas Treatment, its not cheap but it worked.
N T-J

Roncallo · #8 09-01-2006, 08:55 AM

Quote:

Originally Posted by Marlie's

Thank you for the feedback. My '92 500SL has only 53k miles on it and I love it. I am going to purchase the fuel accumulator and perform the 'B' service to see if that will fix the problem.

I wouldent just go and replace parts. A bad accumulator would only cause a delayed start just as if you had changed a fuel filter and were starting it for the first time. Usually these cars will start with less than 10 seconds of cranking after a fuel filter change. That is why my first guess is leaking injectors. Leaking injectors would give you a combunation of a fully discharged accumulator and a flooded engine.

If injector cleaner doesnt fix it, I recommend you start by getting a fuel injection pressure gage and follow the correct proceedures to test the fuel system.

John Roncallo

YuCrew · #9 09-01-2006, 09:06 AM

I have a 380SL that would ONLY hard start when the engine was hot/warm. Cold starts were never a problem. MB dealer said no accumulators available any longer for the car and insisted it's probably leaking injector and highly unlikely to be the accumulator (not just the parts guy but he also consulted one of the mechanics)

Well to make a long story short, I found a new accumulator (IDENTICAL in every respect to original including manufacturer logo), installed it and have had no cold or hot starting issues since. NOTHING else was replaced (not the filter nor any fuel lines).

I don't know if this will solve your problem but it solved mine. Good luck.

Roncallo · #10 09-01-2006, 09:48 PM

Quote:

Originally Posted by YuCrew

I have a 380SL that would ONLY hard start when the engine was hot/warm. Cold starts were never a problem. MB dealer said no accumulators available any longer for the car and insisted it's probably leaking injector and highly unlikely to be the accumulator (not just the parts guy but he also consulted one of the mechanics)

Well to make a long story short, I found a new accumulator (IDENTICAL in every respect to original including manufacturer logo), installed it and have had no cold or hot starting issues since. NOTHING else was replaced (not the filter nor any fuel lines).

I don't know if this will solve your problem but it solved mine. Good luck.

The purpose of the accumulator is to aliviate a hot start problem due to vapor lock. The original poster has a problem after 4 hours. This should not be a hot start condition.

John Roncallo

LeaUK · #11 09-02-2006, 04:06 AM

In my experience and reading throughout this forum the R129 doesn't suffer from vapour locks.

I would seriously consider checking the caps for tracking and give them a thorough clean.

Lea

Marlie's · #12 09-04-2006, 01:24 PM

Thanks for the responses everyone... here is what I've done so far... I have replaced both distributor caps, both rotors, the fuel accumulator and replaced the spark plugs. On another note, I drove the car to Clear Lake (outside of Houston Texas) about a month ago to visit friends. On my way back home, I filled the car with super unleaded as usual, but I remember the pump stating that it was Ethanol (a Shell station). I drove the car home, about 200 miles. For the remainder of that tank of gas which got me to work and back fpr the rest or the week, the car started great every time. Once I filled the car with the usual super unleaded - I was back at the hard start. I tried diferent gas stations and diferent brands, but the same hard start after the car sits for a few hours. I cannot find the ethanol in the city where I live so I can't try it again without driving back to Clear Lake. Now I am not sure if that indeed was ethanol at the Shell station in Clear Lake. Now I am hearing about E-85 that will be available soon. I understand that contains a percentage of ethanol, but the 85 octane scares me. The station in Clear Lake displayed a 93 octane rating. Any thoughts on that?

LeaUK · #13 09-04-2006, 02:40 PM

Interesting - sorry the distribs didn't cure your issue.

The manual states the minimum continual use at Premium grade RON-95 (min 91 for short periods) and so I would suspect you'll run the risk of damaging the engine on anything less.

Gilly · #14 09-04-2006, 07:01 PM

E85 isn't 85 octane. Not sure what the octane rating is. IIRC it's 85% ethanol. Not all cars can use it. Might be 85% gasoline. But I think 85% Ethanol, makes sense. I'd stay away from it if the car isn't made for it. I think it's less expensive but fuel mileage isn't nearly as good as regular ol gasoline. Keeps us less dependent on furrin' oil tho.
Gilly
PS I would have bet on the caps too. Haven't been messing with the spark plugs? You're better off with the recommended plugs on this car.