E-Class (W124) 1984-1995: E 260, E 300, E 320, E 420, E 500 (Includes CE, T, TD models)

1994 e320 misfire at idle and light acceleration? but clears up at WOT?

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Old Aug 17, 2012 | 09:08 PM
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94 e320
Arrow 1994 e320 misfire at idle and light acceleration? but clears up at WOT?

iam workin on my mothers 1994 e320 and she suddenly got a misfire, i put new plugs and wires in and still missfire, cleaned IAT and mass air flow sensor, i started pulling wires one at a time and play around wit the electrical connectors to the coil and iam having a issue the the power/signal wire that go's to the first ignition coil, that supplys spark to cylinder 2 and 5, i verified that all the coils were good by swapping them around, the car run slightly rough at idle and the idle will surge up and down at times, also if your driving the car under a load or wide open throttle the misfire goes away and clears up, also at idle when the engine is misfiring fuel smell and slight black smoke from the exhaust system which is telling me its getting fuel just not getting burnt. does anyone have a ignition wire diagram and can pin out the wire harness anf follow wire to fine a broke wire? i really needa figure this out asap cus this is my mother only ride and they are broke she just got layed off from her job and also my father did, so iam trying to help them out the best i can, the only thing i didnt do is a compression check and swap around injectors, any help is apprciated thanks matt
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Old Aug 18, 2012 | 12:15 AM
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Do a search for code reader. The parts can be purchased at Radio Shack cheaply. It will take ten minutes to make it, ten minutes to read the codes. At most.


How is the wiring harness?
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Old Aug 18, 2012 | 10:09 AM
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94 e320
Originally Posted by neanderthal
Do a search for code reader. The parts can be purchased at Radio Shack cheaply. It will take ten minutes to make it, ten minutes to read the codes. At most.


How is the wiring harness?
the injector/coil harness looks to me it was replaced its wrapped up nice and wire tied down, thats telling me sumbody was in there at one time, i noticed a few wires on the firwall are starting to delaminate and the copper wire is starting to show, iam starting to lean towards its a bad valve orfuel injector, i will dig into it more asap
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Old Aug 18, 2012 | 12:02 PM
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1996 E320 Sportline Cabriolet x 2
Has the wiring loom been replaced. If not now is a good time to do it before the ECU is damaged.

Last edited by WDB124066; Aug 18, 2012 at 12:04 PM.
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Old Jun 10, 2013 | 12:03 AM
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E320
i have the same ise with my 96 i replace the spark plugs an checked the wires for spark. it made it a little better when idle. but it still acts like it has a misfire. i was told it might just be a sensor.
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