96 GC wont run on 6 cyl 4.0 97 eng

[gbic1]

Just installed a used 97 engine into a 96 Jeep Gran Cherokee it it wont start. Ran a scanner on it and had no codes. It has good spark, good compression amd fuel pressure. The injectors are firing and the plugs are getting wet. Engine came complete except oil pan and pick up screen which I transfered from old engine. Engine turns over fine. We tryed another coil and pick up out of old distributer. Now here is the weird part. When I pulled out the plugs to check compression, I only pulled 2 3 4 and 5.(1 is hard to get to and was too lazy to pull 6.) When I hit the key it started! and ran on 2 cylinders. I figured it was just flooded so I cleaned and reinstalled the other 4 plugs and it wont start. If i pull out 2 of the middle plugs it willl run but runs better on just 1 and 6. I double checked the firing order and the direction. I swaped wires around for kicks and it makes it worse. I tryed to runm it of either and it doesnt work either. Checked the crank sencor and cam sensor on scanner and they are working. It acts like timing is off but we never pulled the distributer out. We drove it in with a rod knock only. ???

[Dale Aeppli]

Originally Posted by gbic1

Just installed a used 97 engine into a 96 Jeep Gran Cherokee it it wont start. Ran a scanner on it and had no codes. It has good spark, good compression amd fuel pressure. The injectors are firing and the plugs are getting wet. Engine came complete except oil pan and pick up screen which I transfered from old engine. Engine turns over fine. We tryed another coil and pick up out of old distributer. Now here is the weird part. When I pulled out the plugs to check compression, I only pulled 2 3 4 and 5.(1 is hard to get to and was too lazy to pull 6.) When I hit the key it started! and ran on 2 cylinders. I figured it was just flooded so I cleaned and reinstalled the other 4 plugs and it wont start. If i pull out 2 of the middle plugs it willl run but runs better on just 1 and 6. I double checked the firing order and the direction. I swaped wires around for kicks and it makes it worse. I tryed to runm it of either and it doesnt work either. Checked the crank sencor and cam sensor on scanner and they are working. It acts like timing is off but we never pulled the distributer out. We drove it in with a rod knock only. ???

Check out the crankshaft position sensors 96 & 97 4.0's use completely different numbers. The engine u put in is it from GC or just cherokee dale

[Cam7]

If its not the CPS I would look towards the Timming Chain having Jumped. Turn the engine to TDC at no 1 cylinder and check the distributor should be pointing to #1 on the cap if not the chain jumped or Dist was off.

[gbic1]

Not sure what it is out of. We used the orignal flywheel and crank sensor. What is the difference between GC and C for the engine?. Checked the timing chain and it is not it. Distributer is pointing at number one. Are these known for warping heads and have compression jump between cylinders?

[dksob81]

change the CPS from the old engine and put in the new engine.

[gbic1]

Turns out my running engine was not a running at all. Some one had distributer off on tooth. Runs on all six now.