No Spark on cylinders 2 & 5

[jeffj803]

Alright, I've run in to an issue and am looking for where to go next. My kids car had a misfire at 160k so I swapped out the plugs, plug wires and coils (all OEM). The car ran fine for a week and started running like crap yesterday. I went out and checked it with a scan tool, p0300 with continual misfires on 2&5. When I got it home, I swapped coils and nothing changed. I put a plug tester on 2 and 5 and got no spark.

I assumed it was likely the ICM. So, I picked up an ICM from Napa today and I still have the same issue, no spark on 2 and 5.

So...where do I go from here? Looking at the theory of operation, it seems as if it is still something with the ICM. The PCM will control dwell and timing advance but the ICM is ultimately controlling ignition. I could be misinformer there though.

It was recommended to take a look at the reluctor wheel and see if any teeth are missing. Would a missing tooth cause a no fire or more of a firing order issue?

Reluctor wheel aside, that leaves the PCM. Per my understanding though, the PCM provides timing information to the ICM but the ICM is responsible for firing the coils.

I'm at a loss at the moment; thoughts, education and/or insights are greatly appreciated.

 

[MelsRegal]

Have you tested the resistance of the plug wires for those two cylinders compared to the others?
Did you remove the plugs for those two cylinders and recheck gap and possible cracks?

 

[jeffj803]

Have you tested the resistance of the plug wires for those two cylinders compared to the others?
Did you remove the plugs for those two cylinders and recheck gap and possible cracks?

Yes, I forgot to mention that I determined I have no spark using a spark tester. Resistance in the wires are all good.

 

[Homer Jay]

Check the ICM connector and wires. There could be corrosion or a broken wire. If needed you can replace the connector.

 

[jeffj803]

Alright, I've run in to an issue and am looking for where to go next. My kids car had a misfire at 160k so I swapped out the plugs, plug wires and coils (all OEM). The car ran fine for a week and started running like crap yesterday. I went out and checked it with a scan tool, p0300 with continual misfires on 2&5. When I got it home, I swapped coils and nothing changed. I put a plug tester on 2 and 5 and got no spark.

I assumed it was likely the ICM. So, I picked up an ICM from Napa today and I still have the same issue, no spark on 2 and 5.

So...where do I go from here? Looking at the theory of operation, it seems as if it is still something with the ICM. The PCM will control dwell and timing advance but the ICM is ultimately controlling ignition. I could be misinformer there though.

It was recommended to take a look at the reluctor wheel and see if any teeth are missing. Would a missing tooth cause a no fire or more of a firing order issue?

Reluctor wheel aside, that leaves the PCM. Per my understanding though, the PCM provides timing information to the ICM but the ICM is responsible for firing the coils.

I'm at a loss at the moment; thoughts, education and/or insights are greatly appreciated.

So...sometimes it is something simple yet stupid. I pulled the coils off to verify if any would work in the 2&5 slot, well when I pulled of the 2/5 coil to swap in another, one of the spades was laid over flat. I am fairly certain it was upright when I installed the coil and I didn't feel anything odd when I seated but it was either bent or I bent it. I'm glad it was something simple after all because I was definitely scratching my head. So the original ICM was bad and the replacement ICM fixed the issue. It was 100% coincidental the new ICM 2/5 slot ended up with a bent spade and the original ICM 2/5 slot went bad.