Q I have a 1991 Mercedes 190E which I have owned for the last nine years. I have had no problems with the vehicle up until recently, when it cut out for no reason at all, then restarted and cut out again. It did this two to three times, then was OK for a while.
I followed advice to fit a new crankshaft sensor and all was then fine for a few days, after which it cut out again. I have recently fitted a new fuel pump, but the vehicle still cuts out. Could it be an electrical fault? I don’t want to sell the car as the ride is beautiful.
A Having changed the crankshaft sensor, I would check the continuity of the wiring from the sensor to ensure the problem is not a fault in the circuit. According to my data, your Mercedes also has a separate ignition control unit located on the nearside inner wing. I would check the connections to this to ensure their integrity.
The fault could also be a problem with the ignition coil. When the vehicle cuts out, check if it feels excessively warm. If it is possible to test the system for a spark, this will help confirm if the problem is on the ignition side. If you are still getting a spark, and as you have already changed the fuel pump, I would then check the fuel pump relay, on the offside of the engine bay in front of the battery.
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