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1974 Mercedes-Benz 280 Series 280SE Sedan Base

1974 Mercedes-Benz 280 Series 280SE Sedan
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April 13, 2009, 6:54 am

Robert H

Question: 1972 280SE Even after cleaning or replacing the plugs.

1972 280SE
Even after cleaning or replacing the plugs. Upon starting, this car it runs rich, and then floods out. It just pours black smoke out the exhaust and then dies.

April 13, 2009, 8:25 pm

Elizabeth K

The carbon-fouled plugs were a symptom of your rich condition, not a cause. Here's a short list of things to check, all fuel/air mix related:
air filter!!
cold start valve
temp sensors for air and coolant
throttle posit. sensor
MAP sensor
wiring harness
air inection valve

If that doesn't help you, and there are a ton of things that could cause a Jetronic system to run rich, try doing a search on the mercedes forums on and You'll find a wealth of info out there.

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