Sounds like your on the correct path thinking the CPS.

http://www.greatlakesxj.com/tech/cps.pdf

you will probably need to get one for the 1994 because of the wiring harness plug end. if the plug ends are the same for both years then get it for the model yaer of the tranny. isnt that what it bolts to?

Well maybe i've made a mistake with this motor, here's what i did.
1. pulled out 1994 motor and removed intake and exhaust manifolds
2. intstalled these manifolds on 1988 block and head.
3. installed this motor in 1994 jeep and used all wiring that came with jeep.
4. Switched distributers, alt. brackets, etc.
5. used 1988 flexplate, (which i think is where i made my mistake, they looked the same but i guess i didn't look close enough.)


I pulled the cps and its different than the one i removed from '88 cherokee. So this tells me that Jeep changed the the flexplates and sensors. Will i be able to buy an older cps that will match the flexplate and use that or do i have to switch out the flexplates?

The 1st problem is you have a HO setup trying to run a renix motor. Your going to have all kinds of problems getting it to run...

The TPS on the non-HO engine has 2 connectors that come out of it. One connector (flat one) tells the computer how much throttle is being applied. The other (square) controls the TCU (transmission control unit) which controls shift points. The HO TPS only has 1 connector that goes to the computer. The computer controls the TCU. It is fairly easy to fabricate a small spacer and "widget" to allow the use of the old TPS with the new throttle body (This is a MUST) so far unless you're a rocket scientist and can rewire. This is the only choice. But it's not to hard to make a little adapter. There are several ways to go about it.

EDIT: You mentioned you used the intake and exhaust manifolds from your old motor. Did you use all sensors/tb/tps/wiring from your old ('94) motor as well? If so you may be ok with the topend of the motor.

The CPS is also different between the Renix and the HO models. I want to say that the CPS itself is different all together (as it's not related to the flexplate) but I could be wrong.

according to autozones website, there is no difference between auto and manual cps. But there is deffinetly a difference between 88 and 94 sensors, so i'm guessing i'll have to buy an '88 sensor and splice some wires into the 1994 harness.

Here is what I found out on the CPS. This is for the Renix CPS only.



View of rear of engine showing Crankshaft Position Sensor & Harness highlighted in red. Note: You can not see this save view with the engine in - it's just shown to help you locate the CPS.

CPS: You can check it's basic function but be aware that sometimes the darn things can be 'intermittant' but still read 'ok' when measured due to engine heat/temperature. Even so, these tests will show up a borderline CPS more often than not.

Check the connector first
If you've just stalled out with same symptoms... unplug the CPS & plug it back in. If your motor fires back up you might get off easy, but don't count on it lasting forever. I dunno what doing this accomplishes other than cleaning the connector contacts enough to let additional voltage through to the computer. If unplugging & replugging worked then unplug the connector again and clean those contacts off. Then apply some OX-GARD, or other electrical contact cleaner & protectant (dielectric grease).

There is a distinct possibility that you're not getting a signal due to a faulty connector itself as well. Some people have cured their CPS problems by simply cutting the connector out of the harness and SOLDERING the wires together (Use heat shrink or electrical tape around the wire, of course!) Other's have replaced the connector with a newer, waterproof version from an electrical or automotive supply store.

Test#1 - Get a volt/ohm meter and set it to read 0 - 500 ohms. Unplug the cps and measure across the CPS leads, the CPS should measure aprox. 275 +/- ohms. If it's off by much, replace it.

Test#2 - You'll need a friend to help ya with this one.
Set your volt/ohm meter to read 0 - 5 AC volts or the closest AC Volts scale your meter has to this range. Measure across the CPS leads for voltage generated as your friend cranks the engine. (The engine can't fire up without the CPS connected but watch for moving parts just the same!) The meter should show .5 - .8 VAC when cranking. (That's between 1/2 and 1 volt AC.) If it's below .5vac, replace it.

Desperate last ditch tip to get home or a few more miles from a failing CPS: - Other than the unplug/replug trick... MJR passed on a trick of using a flat bar and a hammer to 'adjust' the CPS by smacking the CPS bracket and forcing a weak CPS just a tad closer to the flywheel. This lets a weak CPS get a stronger pulse and hopefully generate enough voltage to feed a good signal to the computer again. WARNING! - If ya smack it too hard... it'll go in too far and the flywheel will eat the CPS! Start walking.

Either way, if it fails ANY of the tests... you should replace it and save your self some major pain later. If not, at least carry a spare CPS but be aware that it's a royal pain in the ass to change on a cold motor and ya really don't wanna do it at night, on the trail and with a hot motor if ya can help it!