stupid intermittent thing

went for the xj yest morning, turned over fine but no fire. stupid thing. 1990 xj limited w/ 4.0 auto, 4.0 is a swapped ho, but running all renix sensors and computer. i checked the spark plugs, looked wet, smelled like fuel under the hood after cranking, so i believe it was getting fuel. wanted to pull a plug and check for spark, but didnt have an assistant to crank engine for me.has been running poorly when cold lately, so i assumed it was my poorly mounted tps. checked and adjusted tps, was a little off, didnt think it would cause a no-start but need to adjust it anyway, but no change. unplugged and re-plugged cps, no change. checked cps w/ ohmmeter, had 215 ohms, all wires look fine. checked wires all over engine compartment, didnt find anything suspicious. swore a little, no change. gave up. went out this morning to swear at it some more, checked for 12 + to coil, was good. was going to pull a plug and/or coil wire to see if/ where i had spark since the wife was home, but thought i'd just try it and see if it would fire and it popped right off just to piss me off. tried it a few more times and it starts fine. stupid thing. i looked at the coil to see if i saw anything obvious, jiggled some wires, didnt find anything. any suggestions on what to check if it does it again, or something i can check now. been on these forums searching half of yesterday till 2 am, can find anything else. i belive it wasnt getting spark, but dont know why, cps is good. also, its been running poorly when cold for a few weeks, once its at operating temp its fine, but doesnt have much power, kinda feels like a miss till then. adjusted the tps today and it stil does it, was sure that was the problem. seems to be running rich, plugs are fairly black. runs fine when warm though. sorry this is so long, have to vent somewhere, and the dog quit listening.

My guess is the TPS flooded it. With bad CPS you will not have wet plugs because you would not be firing the injectors either.

O2 sensor and/or MAP sensor come to mind. Have you tried unhooking the MAP when it's at operating temp? Sure you have no vacuum leaks, especially at EGR gasket and the EGR valve is operating?

i dont think it flooded. i had tried to start it at 8:30 the first morning, and didnt fire at all, just turned over. when i went to work on it that afternoon was proly 2:00 and still didnt fire. wouldn't it have cleared out by then. i did try putting the gas pedal on the floor after a few tries, dont know if thatwould help this engine but it worked on my old ranger. i asked my ford mech. buddy about o2 sensor and he didnt think it would be that, he thought it would run poor all the time. he thought maybe map or a temp sensor. i dont think i have a vac leak, i have a guage on it and it reads the same as before it was running poorly. thanks for the responses.

You said "spark plugs, looked wet, smelled like fuel " they should not be wet with fuel.

Dirty/corroded/worn distributor cap and/or moisture in the spark plug/coil wire ends will do that. Old plug wires and excessive resistance makes it worse when moisture gets in the system. The spark gets weak or takes odd paths to ground. It sounds like weak spark may be your problem.
Moisture in the 12 volt cable connectors for the coil and dirty contacts between the coil and the ignition control module will also cause problems. The contacts between the coil and the ignition control module are open to the weather. After cleaning mine, my starting time (cranking time) was significantly reduced. A new set of coil wound (helical core) low resistance plug wires also helped. A stock (OEM spec) coil to cap wire is recommended.
When my TPS went bad (motor side) it messed with the timing, it would occasionally pop out of the intake and was kind of dead while accelerating.
My IAC stuck shut, I flooded it a couple of times before I caught on. I had to start it at quarter throttle till I got the problem fixed. It would often die at idle.
Good grounds and dry clean connectors are important, line loss (resistance) or line leaks (12 volt) add up.

dangerranger said:

checked cps w/ ohmmeter, had 215 ohms, all wires look fine.

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If you have an analog voltmeter, plug the leads into the back of the CPS connector, set to the lowest AC scale, and watch the needle as you crank the engine. If you observe the fluctuations, the CPS sensor is sending signals out to ECU. Also, there is another CPS - the Camshaft position sensor -- in your Jeep. It is located in the distributor. When mine went out, the Jeep would fire up after a very long cranking period -- talking 20 secs here. Pull the distributor cap off and check that all distibutor internals look intact. Again, if you have an analog voltmeter, you can observer fluctutations in DC voltage between blue and black wire on distributor connector.

thanks for the responses. i know i dont have the best plug wires, one i pulled off the plug was fairly corroded, boot must not been sealing anymore. i'll have to test w/ an analog meter if it act up again, now i gotta find an analog meter. i thought i was doing good when i found a cheap digital at walmart.