chasing electrical gremlin

'89 xj w/ 4.0 - been chasing this for a while was wondering if anybody has an educated guess on what is going on. When I accelerate the motor wants to lose power for a split second , almost like it is sputtering. When it is doing this i notice my tach drop to "0" for a split second each time it sputters. Sometimes it will run pretty good and other times not so good. At one time i noticed that it would happen when i made a right hand turn. Is there an obvious spot that i could look at for a loose electrical connection?:helpme:

Thanks for all the reply's ................ it ended up being the CPS

What threw me on this one was that it happened
on a right hand turn, and under accelleration...

Was it a bad connection or the CPS itself bad?

Sometimes simply unplugging the CPS and plugging it back in will get it to start or quit dying. There's resistance in that plug. Coulda been something you wouldn't imagine. Bell housing to engine bolts loose has been seen before as has CPS wires melting/grounding on the exhaust.

I can't post a photo of the wire routing but here's something to help test and increase your CPS output.

Renix CPS Testing and Adjusting
　
　
Renix CPSs have to put out a strong enough signal to the ECU so that it will provide spark.
Most tests for the CPS suggest checking it for an ohms value. This is unreliable and can cause some wasted time and aggravation in your diagnosis of a no-start issue as the CPS will test good when in fact it is bad.
The problem with the ohms test is you can have the correct amount of resistance through the CPS but it isn’t generating enough voltage to trigger the ECU to provide spark.
Unplug the harness connector from the CPS. Using your voltmeter set on AC volts and probing both wires in the connector going to the CPS, crank the engine over. It won’t start with the CPS disconnected.
You should get a reading of .5 AC volts.
If you are down in the .35 AC volts range or lower on your meter reading, you can have intermittent crank/no-start conditions from your Renix Jeep. Some NEW CPSs (from the big box parts stores) have registered only .2 AC volts while reading the proper resistance!! That’s a definite no-start condition. Best to buy your CPS from Napa or the dealer.
Sometimes on a manual transmission equipped Renix Jeep there is an accumulation of debris on the tip of the CPS. It’s worn off clutch material and since the CPS is a magnet, the metal sticks to the tip of the CPS causing a reduced voltage signal. You MAY get by with cleaning the tip of the CPS off.
A little trick for increasing the output of your CPS is to drill out the upper mounting hole to 3/8" from the stock 5/16", or slot it so the CPS bracket rests on the bell housing when pushed down. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.

　
　
Revised 01-26-2013

i think the wiring on the cps was crappy, sometimes it would run good (short spans, while the connectivity was good) then take a corner and hit some bumps and it would run like crap - been chasing this for 2 yrs. I had changed a bunch of different sensors & relays etc. through the span of troubleshooting this. I am stoked that i can put the issue behind meparty1arty1arty1:

I know how you feel. I once had an 89 with intermittant
no-start issues. Chased the problem for about 2 years and
finally found the ground nut at the dipstick tube loose.
It's a great feeling when you fix one like that.

Glad you found it.