Missfire help wanted.

[RonH]

Hi everyone!.My 86' 190e 2.0 ltr. has developed an annoying missfire at the weekend.You can feel the missfire in low revs as you pull away and also the tickover has become lumpy.Pulled the plugs and found No1. plug to be sooty.Put new plugs in...no differance.Substitude No.1 lead ....no differance.Replaced rotor arm and distributor cap....no differance .Checked out the votage at diagnos socket, resistance at switch unit and the resistance on the coil...as per Haynes manual.....all ok! Took the car for a spin...3 other plugs are a nice colour, No.1 still sooty!.
Will perform a cylinder leak-down test next , after making a tester.
Does anyone know if there is something else in the ignition system that I need to address that might be causing this problem that only seems to be affecting No1 cylinder ?Your help would be much appreciated !

Many thanks Ron H.

 

[malcolm E53 AMG]

Might be a distributor problem. I'ts probably worth taking the car to a tuning specialist and letting them do an assessment, for £30 you'll get a full readout of the engines state of health.

 

[television]

Check that you have 12 volts at coil primary +

malcolm

 

[RonH]

Many thanks for your rapid responses,........ much appreciated !.Will take it to be analysed, save a lot of guess work and time.Hope I can find someone that not only knows how to work a machine, but can also read the results correctly! ( I'm affraid I'm out the old school....believe a machine is only as good as the person using it ! )
Many thanks Ron H.

 

[television]

Your thinking is not far out, my post was simple check that you do have 12volts present, its very basic, but important and often over looked. as the OVR can go down causing many odd faults including rough idle

malcolm