XJ No Start

Just purchased a 1990 cherokee and it turns over but doesn't start. It ran but had a blown head gasket. It got a 94 model 4.0 from zj and wouldn't start. So they replaced sending unit, coil, starter, and idk what else was replaced. then i got it and unsure what to do. I checked power at the coil and it wasn't getting any power but I ran a jumper wire and fixed that but checked the plugs and didn't seem to get spark. I've noticed they have different coils for 90 and older and 91+......think that could have anything to do with my problem??? O and I checked the cps and its new

First off, depending on the knowledge level of the Previous Owner (PO), they may have installed the newer engine without regard to the flywheel/flexplate. If they used the 94 parts the CranKshaft Posistion sensor (CKP, often wrongly I.D. as CPS) won't read correctly and that beast will never run.

The CKP is the only sensor on a RENIX (Renault-Bendix) XJ that will kill it.

Your battery and cable ends, as well as all grounds, must be in top-notch condition. XJs will crank very well, but if the voltage drops too low the electronics don't work. For the RENIX to run the CKP must send a proper signal to the ECU or it won't go.

Do a search for RENIX, CPS (CKP), no start, etc., and check out this link to our FAQ forum: http://www.naxja.org/forum/showthread.php?t=101119

Thanks alot, I'll look into it

it got the 94 grand cherokee flywheel, so do I need to buy 94 grand cherokee ckp?

No. You need to get a RENIX flywheel so that the CKP gets the right signal for the RENIX ECU.

I think Crown makes one, and other aftermarket manufacturers too. I would price the dealership, sometimes they can be reasonable on some parts.

NAPA has them listed for about $100; Centerforce wants $221 for theirs + shipping.

When I talked to the guy today that had it done he said the old flywheel wouldn't mate to engine. I'll buy used just incase it wont work but thanks alot for the help

redneckabbott said:

When I talked to the guy today that had it done he said the old flywheel wouldn't mate to engine. I'll buy used just incase it wont work but thanks alot for the help

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I don't think the crankshaft is different in the 4.0, xj or zj or yj. The only difference should be in the "notches" on the flywheel and the timing of the signals based on years made.

You can check with the dealership on the part numbers to be sure.

IIRC even the 258 and 4.0 are similar at the back of the crank - enough so to build stroker motors for any year.

"Old flywheel wouldn't mate" sounds hinky - and I don't envy you having to pull the cover to check, much less the engine . . .

x2 on everything said. you need a renix flywheel(87-90xj) and the old renix flywheel should have mounted to the 94 4.0

This has the auto so I need the flexplate correct?

redneckabbott said:

This has the auto so I need the flexplate correct?

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correct, a renix flexplate