88' K5 TBI - No Spark

[Charleshugh]

Hey guys, I drove my blazer less than 5 minutes to a neighbor's house, parked it, went to leave after 10 minutes and there was no spark. After digging into it I found I wasn't getting any power to the ICM with the key on and while cranking. Replaced it and the problem persists. I am getting fuel through the injectors while cranking and I also have a constant 12V to the coil. Any ideas on what it might be? Since I'm not getting power to the ICM that makes me think there's an issue with the wiring between it and the ECM.

 

[Charleshugh]

Hey guys, I drove my blazer less than 5 minutes to a neighbor's house, parked it, went to leave after 10 minutes and there was no spark. After digging into it I found I wasn't getting any power to the ICM with the key on and while cranking. Replaced it and the problem persists. I am getting fuel through the injectors while cranking and I also have a constant 12V to the coil. Any ideas on what it might be? Since I'm not getting power to the ICM that makes me think there's an issue with the wiring between it and the ECM.

Also, is power supplied to the ignition module from the coil or from its other wiring harness?

 

[Blue85]

The injectors won't fire unless the ECM sees signal from the distributor pickup, so that part must be working. There are 2 ECM fuses, I think they're labeled A and B, make sure both are good.

 

[Wes Harden]

Here is the diagram