I just bought a 1991 300sl and love the car. Although I have one (maybe two) frustraring problems. When starting the car it will immediately stall. The second hit of the key the car will start and sputter for a few seconds and sometimes stall. There is a smell of gas in the garage. The previous owner took the car to a shop and they replaced the timing chain. That shop told me the next step would be to replace the two fuel pumps($500) I took the car to another shop and he thought it was the fuel injectors. He cleaned them and replaced the filters($400) The car runs the same. Now he wants to replace the injectors($500) Im not sure what to do. Any suggestions? Are the injectors easy to replace? Do they require any tricks or special tools? the car has 140000 miles. After starting and running for a minute the car runs perfect.

Bareftr02,

I have a 1990 300 SEL. I think we have the same engine and we definietly have the same problem. You didn't mention if you had trouble with cold start, hot start, or both. I am assuming you have a CIS system on your car. There are numerous fuel injection checks you can make but you will need a pressure guage and troubleshooting procedure. Items that can effect starting include the fuel pump & check valve, accumulator, cold start valve, electro-hydraulic accuator (EHA), and fuel pressure regulator. If these items check out, I read recently in Mercedes Enthusiat that cold solder joints on the controller circuit boards or failing electrical connections can also cause misleading problems. Keep after it and post back if you solve your problem.

Motorhead

Motorhead

It realy doesnt matter whether the car is hot or cold it sometimes will start right up and then sometimes it takes a few hits of the key. then is will sputter for the initial take off and will stall if you dont feather the throttle. After the car will run perfect. the mechanic checked the fuel pumps and couldnt find a problem. He wants to replace the injectors which im sure i can do myself. I havent heard of electrical problems. I heard that the coolant temp valve? might be a cause. im leaning towards replacing the injectors that appears to make the most sense.

Bareftr