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Rough Idle: TWO coils disengaged, with no difference to idle??
2002 C200K W203 m111.955 (M20EVO)... 203k km on the clock.
So, I have been hunting the cause of a sudden rough idle after cleaning throttle body, MAF, spark plugs, removing S/C manifold to have a look at that infernal bypass valve, etc.... but, it seems that the idling was a new and unrelated problem: I found that disconnecting ignition coils on both cyl 1 AND 2 (accidentally), made no difference to the rough idle and the very generous odor of gasoline from the exhausts. Is it even supposed to be able to run on 2 cyl only? Went to bed in a REALLY bad mood. Next morning, and cyl1 has magically fixed itself: idling suddenly much better, but disconnecting cyl 2 not making any difference connected or disconnected. Swapped spark plugs around, but everything still pointed to cyl 2, and was confirmed when my wife arrived home with 4 brand new spark plugs from dealers.
Cyl 2 still missing in action. Next step will be to swap ignition coils around - which I have done before the new spark plugs was installed, and even in a brief run of less than two minutes, the newly cleaned plugs seemed to have regained a lot of black soot - (really) rich running, yeah? - while problem seemed to stay at cyl 2 even with different coil. Which will basically leave injectors as cause, correct?
Symptoms I still have is the missfire on cyl 2, and a really strong petrol smell from the exhaust. I had no chance to swap new plugs around yet, only the ones I cleaned. The problem also showed up DIRECTLY after I have cleaned MAF, throtlle body, so that I was concerned that I did something wrong during the re-assembly.
My trusted ELM327 to BlueTooth on android tablet, is giving me a finger - insists on saying 'cannot' find ECU when asked for list of logged faults. So... just have to fix THAT lil problem as well to get some real info from the car itself.
It is going to be a really frustrating two day coming up (car-wise), since I am a Christian and will be celebrating Good Friday with my family, but I will report on any future progress as soon as it takes place - should anyone be interested!
Ok, it is NOT the ignition coil, and it is NOT the spark plug - all established via process of elimination. I have no solution to the sudden misfire on cyl2 - seems like fuel injector remains a possible culprit; But, I got my Torque Lite up and running, and the readings doesn't give me direct clues. These readings were present BEFORE I started operating on my car, at which time cyl2 was just fine. Any help or ideas, PLEASE?
In the meantime, here are my readings with plans of action for each. Just remember, a week ago I did not have a CLUE about what I was doing, hehe. So, I didn't solve a SINGLE problem in round number 1!
p0340 Camshaft Position Sensor Circuit Malfunction
p0102 Mass or Volume Air Flow Circuit Low Input
p0010 Mass or Volume Air Flow Circuit Malfunction, Hot-film mass-air sensor ME-SFI – fault code description.
p0135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
p0414 Secondary Air Injection System Switching Valve A Circuit Shorted
So... I guess my MAF may be shot - I did a thorough clean, and I am still getting p0102 and p0010 which I was getting before disassembling stuff to clean.
It is the sensor in the red circle, correct? I you read this, 230Sport Coupe, can you confirm whether the problem was the sensor itself, or the wiring?
p0135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1): should be able to get this one with help from the doit guys:
04-01-2021, 08:13 PM
Rough Idle: TWO coils disengaged, with no difference to idle??
