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[FIXED] 2004 Subaru Forester no spark on #4 cylinder.
2004 Subaru Forester has about .9 volts at connector while running backprobed at ECU about half that on #4 which is not firing. Replaced original ECU because car died progressively and finally wouldn’t start. Installed a used ECU and now it seems that there is an issue with it also. I’m not sure what the voltage is supposed to be but 1,2 and 4 are all similar so I’m assuming there is a problem with the ECU. Am I wrong?
Check your wiring ohm test each wire going to #4 and load test it with a test light. Something tells me you will have high resistance on them or possible a open in the harness.
Problem solved! Bad pin connection at ECU. COP ignition. #4 (B15) had sloppy fit causing high resistance. Son is VERY happy now lol. I’m working 7-10’s and some 12’s and haven’t had much time to diagnose it. He’s an aspiring tech and though I am not I’m trying to teach him not to be a parts replacer. Fuel pump, relays, temp sensor, cps, cam ps, timing belt were all suggested to be bad by his friend/mechanics lol. Told him we’re not replacing so much as a fuse until there’s proof of failure. This site et al is the best! Would’ve pursued this as a career when I was a kid If there was a Scanner Danner 45 yrs ago and a site like this. Thanks for the input!
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