snowman313

i am looking at buying a 2001 cherokee with 80,000 miles on it that the original owner put a 2000 short block in it after loseing oil presure in the original engine and after swapping the head and everything over in will not start is there any difference in the short blocks ie. crank sensor distributer timing or any thing else that could cause this or did he just screw something else up. The reason i ask is because a buddy of mine bought a long block from a rebuilder and had to turn the distributer about 90 deg. to make it run.

BuckB91XJ

2001 XJs have the Coil On Plug ignition. I believe the 2000 XJs do too. If you have a 2001 with a 2000 4.0 litre and it has a distributor in it, that very well could be your problem. somebody who didn't know what they were doing tried to convert it back over to distributor ignition. Wiring could be all fouled up.

snowman313

I guess i never thought of the posibility of a distributerless ignition i have not even looked under the hood, just going on the owners story he had some back yard shop do the work for him and thats all i know for now. my thought is the crank trigger may not be correct do you know if it is removable or is it part of the crank because i have seen people forget to swap it to the new engine before.

BuckB91XJ

I've never dealt with the crank trigger on a jeep with COP ignition, sorry can't help you there. I do know the Crank position Sensor (CPS) on the older XJ 4,0s are all pretty much the same and they are removable.

snowman313

well i finally got it home and popped the hood and sure enough distributorless i started diagnosing thinks and have no spark i have tracked it down to no crank signal to the coil packs i tested the cps with instructions from a hayens manual and it shows good any other ideas also they think the shortblock is from a comanche pickup mabe a 91 model i checked and the flexplate is the same for both vehicles

snowman313

after doing some research the flexplates are different but i think i nave the right one i'm wondering if the timming between the cam and crank sensor is off any ideas.

tiwvr1

Sounds like a big PIA. I would of left it for someone else.

BuckB91XJ

You will need to marry up the flywheel, CPS and coil pack ignition all from ther original motor in order for it to work correctly. If you have the original CPS and coil packs but, a different flywheel. I guarantee you that is your problem. If that magnet in the flywheel isn't going by the CPS in just the right spot, you'll get no spark and no fuel injection pulse.

alloutperform

hot damn!!!!! a live thread on my issue.... ok i just swapped a 96 shortblock into a 2001 i'm a professional so i don't need color by numbers... i did make the mistake of not swapping out the flywheels and i will address that after lunch but does anyone know how to sinc up the cam trigger? it has no noticable tdc mark on the pick up...i can't imagine it just figures it all out on its own.