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Registered
1991 Mercedes Benz 300SL
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7 Posts
Discussion Starter #1
HELP!

I have a 1991 300SL with 90K on the odometer. It runs great EXCEPT...
in hot weather (about 80 degrees or more), from a standing start, when attempting to accelerate the engine seems like its going to stall. The car barely moves at all. After a few sputters, it starts up. Once its going there is no problem that I have noticed. It seems like a fuel issue...maybe.

I can't figure out why this would happen in hot weather only...the car runs great in the winter! Does that make any sense?

Does anyone have any ideas? Thanks.

CBJ
 

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Registered
1991 Mercedes Benz 300SL
Joined
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7 Posts
Discussion Starter #5
Hello CBJ,

Welcome to the forum

When is the last time you had a tune-up? Spark plugs, fuel injetcion service, transmission service, etc?
All done very recently {2 months}. In fact, I thought that fixed the problem...until Thursday!
 

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Greek God of the R129
SL500-500SEL-190E
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8,373 Posts
You can't easily vapor lock a fuel injected car, the fuel is moving to fast unlels you run the fuel line on the exaust it would not happen.

You have the a/c on, so you are pulling a load on the engine.
I don't know if your car has an speed sensor on the a/c compressor.
Most likely it does, check it.

Look for the idle adjusing valve sticking or not geting the proper signal.

Regards.
aam.

PS.
Besides the fuel line is going through the a/c for additional cooling.
German engineering. ;)
 

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Registered
'90 R129 300SL-24, 94 C140 CL500, '92 W140 400SE,'98 W210 E300TD
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30 Posts
Hi there,
I'd go with either the IAV (idle valve) or coolant temperature sensor. I had a very similar problem on a W126 300SE (which has the same M103 engine) that I sold last year. Cleaned the IAV, replaced the sensor (located in cylinder head near bulkhead/firewall) and car ran like a dream.

Hope this helps.

Best Regards,
Mark.
 

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Outstanding Contributor
2003 SL500, 2003 SL55, and four R129s
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4,270 Posts
I would check the ignition and injection systems for fault codes. If that found nothing, I would follow the electrical test procedures from the engine diagnostic manuals found in the R129 Tech DVD and the WIS.
 
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