QuestionQUESTION: Hello, symptom is rough running, bad fuel economy, check engine light 3 codes, injector circuit #1, misfire #1 and front HO2S low bank 1. I checked fuel kpa running and static are good. #1 injector and plugs were replaced at another shop. they said #1 injector was not working. All wires oHm out ok from injector to ecm terminals. have Ubat voltage at all injectors static. #1 injector with noid light is irregular comparred to other 4. I think ecm is problem with grounding switch inside ecm. I have to tell my custome rthat they may need to spend $1,000 for new ecm. want to be sure, does this sound right to you?
ANSWER: Clint, Never had one fail. Normally its a cap, rotor, wires and plugs and it straightenes right up. Did you check all the Turbo hoses for holes? Instead of doing these other tests you should have started with the basic stuff. Thats the problem with generic scanners. They lead you down the wrong path. Roger
Clint, What kind of response were you looking for? Irregular pulse on 1 injector? You are running tests on things that dont make any sense. Its nice that you did all these tests but Im telling you that these ECM's rarely fail. You never told me if you did a Compression test so how the heck do you want me to respond? You are obviously a qualified technician. I deal with a variety of people on these forums. I apologize if you didnt get the answer that you wanted. Roger
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QUESTION: Roger, I totally appreciate your experience. I have followed your forum this is why i was asking my question. This is not a usual problem. All basic's have been covered. the reason leaning towards ECM is i clear all codes. the very 1st code up is injector #1 circuit fault. then after awhile #1 cylinder misfire. The misfire is from the injector fault dumping fuel and #1 cylinder is wet, to much fuel to combust.KOEO shows uniform bat voltage, KOER shows an unmeasurable fluctuation in #1 injector, all others are measurable with steady on/off pulses. I'm thinking ECM due it handles the ground for the injectors. This is the only thing i can come up with. I was hoping someone else may have ran across this before to ease my mind about a $1,000 ECM. I know this does not happen much but when you have worked through and ruled out a mechanical fault with #1 cylinder, and good intake gasket, fuel kpa and static kpa all good, no vacuum leaks, seems like is only option. I also thinking that most of those areas tested would have given me different codes anyway.
AnswerClint, its too bad you dont have a good known ECM to at least test it for this problem. I would try to find a used one to use as a tester. You dont want to buy the $1000 ECM, plug it in and thats not the problem because you will be out $1000 bucks. Been there, done that. Not sure what else to tell you on this one. Roger
