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CPS question.

Posted: May 10th, 2017, 2:31 pm
by zlieberman
I have a 4.2 block that I am in middle of swapping a 4.0 head on and I can't get it to start. I have an aw4 transmission out of a cherokee and also am using the cherokee flex plate. The harness and computer is from a 99 cherokee that has been stripped down to the bare essential in order to make it run. The engine will crank, has spark, compression and fuel yet it refuses to start.

Is it possible that the 4.2 crank bolt clocking for the flex plate is different than that of a 4.0 crank causing the CPS to read incorrectly?

Any other suggestions on possible causes would be much appreciated. I have been driving myself crazy over this thing for over a week now and have tried everything I can think of. I'm almost to the point of just swapping Ina complete running 4.0.