Buick Coil Pack test

[Maverick_53]

Hello I have a 97 buick Lesabra with a 3800 engine that has a misfire on cylinder #5 (PO305).New spark plugs have been installed,plug wires were checked(ok).Engine run fine,other times it misfires,it is not a fuel related problem,engine is mechanically fine.Q.Does any one know how to check the ignition coil packs(primary and secoundary circuits) with a digatal mulitimeter? Also the correct way to test an injector? Or maybe you have already encountered this same problem and can tell me how to remedy this problem.
Thanks Maverick
11/4/05

[maxwedge]

Check for corroded connections at #5 injector, when it misfires, if it is at idle see if there is spark to that plug, if possible. Very hard to really check an icm with circuit testers, Autozone I believe has an off car tester, but they can be wrong. Switch coils and see if the miss moves, that confirms the coil is bad.

[stuzman]

Originally Posted by Maverick_53

Hello I have a 97 buick Lesabra with a 3800 engine that has a misfire on cylinder #5 (PO305).New spark plugs have been installed,plug wires were checked(ok).Engine run fine,other times it misfires,it is not a fuel related problem,engine is mechanically fine.Q.Does any one know how to check the ignition coil packs(primary and secoundary circuits) with a digatal mulitimeter? Also the correct way to test an injector? Or maybe you have already encountered this same problem and can tell me how to remedy this problem.
Thanks Maverick
11/4/05

You can check the primary and secondary resistance of the coils, but it's not a guarantee that it's okay even when the resistance is in specs. A coil can have a shorted winding or two and an ohmeter will never pick it up. Of course, if you have a shorted winding to the iron core or a catastrophic failure, then an ohmeter can pick it up. Unfortunately, most coils don't fail this way. You can check the signal to the coil(s) with a scope which would show any abnormalities with the coil(s). Without the proper test equipment, moving the coil as Max says is a sure way to confirm the problem.

[Maverick_53]

Thanks
I switched the coils today.I will drive and recheck the codes to see if the miss moved with the coil in question.I appreaciate the information.
Thanks Maverick