Billy H

Jasper reman 4.0 L . Cranks over will not start. cam sensor set to TDC on compression stroke . New Crank sensor with good siginal . compression ok , has spark. It acts as if the timing is off.
Back fires through throttel body. We did try to start it with the cam sensor not properly indexed at first. Any help is apprecated !! tnx

jordan96xj

Did you double check the spark plug wire firing order? Some of the diagrams on the web are incorrect. Here is a photo that is correct:

Symptoms you mention are also consistent with incorrect spark/wire order.

https://www.cherokeeforum.com/f2/dis...8/#post3066876

dave1123

I haven't heard many good things about Jasper rebuilds. I hope yours is the exception.

OK_XJ

After my rebuild I had the same problem. It turned out the distributor was one tooth off. I had to have the rotor pointing just past the number 1 terminal when it was at TDC.

BlueRidgeMark

I'm pretty sure that's because sometime, somewhere, somebody photocopied a page from a Chilton or Haynes manual and posted it on a forum. It got copied from there and spread all over.

Chilton/Haynes are garbage.


Billy, save yourself some pain, suffering, wasted time, aggravation, and possible towing charges. Before you install that motor (if you haven't already), trot down to your nearest Jeep dealer and buy OEM sensors. I guarantee that Jaspar used the cheapest aftermarket sensors they could find, and they will fail you very soon.