No spark help

[Bfitz607]

Hey guys, my wife a 1997 TJ 2.5 auto. Its a winter car for her and its time to get it running. I've been trying to tackle a no spark condition for the past few weekends. The jeep has a new crank sensor, new coil, new cam sensor, new cap, new rotor and wires ohm out good. I replaced the entire harness with one out of a similar model jeep (had to swap over a few connectors from the old harness) and it has a brand new PCM. This thing will crank all day long and still not produce spark from the coil to the distributor.

ANY and I mean ANY advice would be greatly appreciated. Im even willing to sweeten the pot with a $20 venmo to anyone who can pin point the problem.

Hope to hear from yall soon!

 

[Chris]

Why was the harness replaced? Did it have this issue before replacing the harness? I’m betting this issue revolves around the harness.

 

[TJ4Jim]

What brand crank and cam sensors did you install and can you test for 12 v at the coil while cranking.

 

[Blondie70]

I had a no spark with a bran new cam sensor. Maybe try a better brand like Echlin ? Mine was a chinese one.

 

[Bfitz607]

Why was the harness replaced? Did it have this issue before replacing the harness? I’m betting this issue revolves around the harness.

The harness was replace because the previous owner had hacked the hell out of it, along woth a fair amount of chafing.

 

[Bfitz607]

I had a no spark with a bran new cam sensor. Maybe try a better brand like Echlin ? Mine was a chinese one.

Not positive on the brand, im sure it was a cheap Chinese one though.

 

[Bfitz607]

What brand crank and cam sensors did you install and can you test for 12 v at the coil while cranking.

Does the coil have to be plugged in a back probed to test? Or can I crank unplugged and test at the connector

 

[Bfitz607]

this is the cam sensor used.

 

[Bfitz607]

Can anyone verify all of the grounding points? Or provide a wiring diagram?

 

[TJ4Jim]

Does the coil have to be plugged in a back probed to test? Or can I crank unplugged and test at the connector

Unplug the harness connector and test the connector for 12V while cranking.

Also turn your key to the run position (not start) and listen, can you hear the fuel pump prime for a few seconds and shut off. A bad crank sensor will not enable the pump to run.

Check out the resource section for your Service Manual and thumb thru.