BlkndGoldCutlass Posted November 11, 2013 Report Share Posted November 11, 2013 ok so just this weekend i finished putting my '93 lumina Z34 back together. i put on new heads and cam carries, all new vacuum and fuel lines, new fpr, o2 sensor, canister purge valve, temp senson, oil pressor sensor, plugs, wires, fuel pump, fuel filter, new timing belt, alternator, accessory belt, intake air temp sensor, and other misc stuff. even after all that i still have a slight misfire. the only thing i really haven't replaced would be the ICM and the coil packs. I'm almost positive that is my issue but my question is that if one goes bad would it cause just a slight miss fire or wouldn't it be more noticeable? ive always experienced that if a coil pack goes bad it creates a much larger problem. Any insight would be much appreciated, thank you Quote Link to comment Share on other sites More sharing options...
redgrandprix Posted November 11, 2013 Report Share Posted November 11, 2013 i had a coil go bad not too long ago and it was only noticeable under a decent amount of the throttle, a coil can cause a much larger problem if say you wash a cylinder down causing a lot of friction on the rings, this sounds like maybe your coil is in the process of going bad, you could always test them with a multi meter or have oreilly's test your icm for free Quote Link to comment Share on other sites More sharing options...
55trucker Posted November 11, 2013 Report Share Posted November 11, 2013 After all that work I see no mention of servicing the injectors. You may very well have one that has a bad motor. You want to locate the cylinder that is not firing properly and after finding it then diagnose whether the problem is spark or fuel related. Quote Link to comment Share on other sites More sharing options...
BlkndGoldCutlass Posted November 12, 2013 Author Report Share Posted November 12, 2013 oh now that you mention it i forgot to add that i replaced 3 of the 6 injectors b/c they were going bad. i bought a coil today to try and locate the issue. ill try to do that tomorrow after school. How do you check the coils with a multimeter? Quote Link to comment Share on other sites More sharing options...
BlkndGoldCutlass Posted November 12, 2013 Author Report Share Posted November 12, 2013 what amount of resistance am i looking for? Quote Link to comment Share on other sites More sharing options...
55trucker Posted November 12, 2013 Report Share Posted November 12, 2013 The GM service manual itself doesn't display an *appropriate* coil resistance for a baseline (I've not had a coil failure as of yet so I'm not sure but if one does have a new coil on hand you can compare old vs. new) , the techie when diagnosing a possible coil problem makes use of a spark tester to determine whether the secondary side of the coil is strong enough to jump the plug gap. I do have one of these in my box (ST-125) , they're only approx $19. http://www.corvetteactioncenter.com/tech/diagnostic_tools/diagnostic_tools2.html Quote Link to comment Share on other sites More sharing options...
BlkndGoldCutlass Posted November 14, 2013 Author Report Share Posted November 14, 2013 Well I checked all the old coils with my multimeter and compared them to a new one I bought. The new one read 5.5ohms. The old ones read 5.6, 7.75, and OL. So I replaced the last 2 Nd she runs beautifully. I figure I might as well replace the 3rd one too so ill end up doing that later. Thanks for all the input fellas Quote Link to comment Share on other sites More sharing options...
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