Anyone have any idea on Ignition Coil trouble shooting ? I tried the procedures in my Hayes book, and got completely opposite results, infinite ohms when should be resistance, etc. I tried 3 other coils with the same result. All could not be bad ? I got a ECU trouble code for a misfiring cylinder 2, and thought it would be the coil (has new plugs).

thoughts anyone ?

thanks to all!

 

I had the same problem - the ohm readouts can be useless, as they read fine on my ignition coils and one of them was still causing a misfire.

You can tell for sure that it is the ignition coil by switching coils with the cylinder next to it ... I.E. switch the coil on 2 with the coil on 4.
Then drive it until the ECU code comes on - if the misfire has moved to cylinder #4 - you have found your bad ignition coil.

good luck

 

infinite resistance means they are in good shape, reverse the leads and you should get a resistance but not 0 mine read about 300-400 ohms. check your fuel injectors for misfires. ive currently have 2 misfires and i know my bad coil made them go bad. so ive changed the bad coils and replaced the bad injectors.

 

Are you sure you are checking the coils correctly? it would seem unlikely that all three coils check out bad... but possible...

 

I had this problem a while ago, and it turned out I had several bad coils, seems they can affect one another when one dies. I couldn't confirm it with a multimeter or by switching coils but the local garage with their fancy OBDII equip. said I had multiple bad. When I replaced all three front ones it fixed the problem. While you're at it, replace the coil condenser, its a little square plug at the front driver's corner of the engine, they said it can cause coils to die also if it stops protecting them from power surges. About $5 from dealer.

Finally, did you consider injectors as an differential diagnosis? They can cause the same symptoms.

 

where is the plug located?

 

What is the problem code you are getting? Could be the fuel injector.....just bring it to Aurora...I"ll fix it ;-)

 

i had the same problem, my dealer told me a good way to test is to unplug the coil you think is bad, if the car runs worse, then thats not the coil that is bad, if it runs the same... then that is the coil that is bad....

 

Nick, drop me an email. I'd like to talk to you about working on my car.

david

dbrown @ ieee.org