I've tried everything, and my jeep still won't start.

[Ecomike]

Well I finally found it throught NAPA and the Stealership when I asked them for a stator or pick up coil. I'll research the IAC and coolant temp. sensors. I think that something is throwing off either the spark or injector timing. I used a multimeter on the injector wires, and it was getting a good voltage pulse. However, after making sure it had spark we poured some gas into the intake throat and it still didn't even sputter, which is why I believe one of the timings to be off.

Which just confirms what I said below, it was probably already flooded. Try the peddle to the metal trick for a good minute, or more and see if it doesn't finally fire up!!!!! If it does fire up it's one of the items I listed below giving you problems. It doesn't take much to flood it.

 

[xj2win]

Well I just called my sister and had her hold the gas on the floor while turning it over, and it started right up. :yelclap: I'm having a hard time deciding if I should buy any parts for it, or if it's possible that it was just too cold and something froze up and it will run fine now. Any thought on reglar maintenance stuff I should replace on the injector or spark circuit would be great.

 

[Ed in North Ga.]

Well I just called my sister and had her hold the gas on the floor while turning it over, and it started right up. :yelclap: I'm having a hard time deciding if I should buy any parts for it, or if it's possible that it was just too cold and something froze up and it will run fine now. Any thought on reglar maintenance stuff I should replace on the injector or spark circuit would be great.

What Ecomike told you to do, is a WOT test (wide open throttle)- it bypasses a long list of sensors-
it could very well be any sensor in the start circut, or the ECU itself-

If your not into working on the real insides of electronics on these, it might be wise to have the Dealership diagnose it- If not, were a wide range of home mechanics in here, we`ll be glad to help. Thats what was always here for in the beginning.

 

[CrawlingCritter]

During engine cranking the ECU ignores the O2 sensor. For the engine to start the ECU has to read the O2 sensor. In WOT (wide open throttle) the ignition system ignores the O2 sensor. Sounds like your O2 sensor is dead.

 

[truck2hi2cu]

!!!1

:shiver: :shiver: :gonnablow i also have a problem with no start/took my toy for a short ride .shut it off for 10 minutes tried and wouldnt start.no power to coil,so i changed crank sensor/still nothing!!!so i tried ign switch/still nothing called local dealer and they said computer/well still nothing!!.i disconnected battery for a overnight charge /just for fun i reconnected battery and turned the key...and it started and ran for 30-40 seconds and quit####i have done this about six times with same results.PLEASE HELP///TIME TO FIX IT OR SHOOT IT!!!!!!!!thanx /vinnie 92xj 4.0 auto 4wd

 

[truck2hi2cu]

:shiver: :shiver: :gonnablow i also have a problem with no start/took my toy for a short ride .shut it off for 10 minutes tried and wouldnt start.no power to coil,so i changed crank sensor/still nothing!!!so i tried ign switch/still nothing called local dealer and they said computer/well still nothing!!.i disconnected battery for a overnight charge /just for fun i reconnected battery and turned the key...and it started and ran for 30-40 seconds and quit####i have done this about six times with same results.PLEASE HELP///TIME TO FIX IT OR SHOOT IT!!!!!!!!thanx /vinnie 92xj 4.0 auto 4wd

 

[CrawlingCritter]

RE: truck2hi2cu

This could be a bad EGR valve. If it's stuck open it will cause a rough idle (if you can call it that) and then the engine dies. The EGR valve is located on the driver's side of the engine. It can be removed and the hole covered with a plate. Removing EGR will improve engine power and worsen MPGs.:flame:

 

[Ecomike]

During engine cranking the ECU ignores the O2 sensor. For the engine to start the ECU has to read the O2 sensor. In WOT (wide open throttle) the ignition system ignores the O2 sensor. Sounds like your O2 sensor is dead.

Some of the above is not correct. The engine can start and run with the O2 sensor disconnected, or even dead. The ECU does not use the O2 sensor during engine warm up.

You are correct that at WOT the ECU ignors the O2 sensor. IN fact at WOT trying to start it, all it does is use the CPS (or CKP) and synch sensor in the distributor and it shuts off the fuel injectors.

So we now know that he has good fuel and good spark, and a good CPS and dizzy synch sensor, and the MAP sensor is probably OK too (they rarely go bad and rarely cause starting problems) . All that is left is the CTS, AIT, and IAC. My money is on a dirty, clogged IAC (also called an Idle Stepper motor, it is next to the TPS, Throttle Position Sensor on the side of the throttle body), or bad IAC, or a bad +B latch relay that operates the IAC on shut down thus setting the start up air flow setting, or a bad IAT sensor.

truck2hi2cu,

I would look into the IAC and see if it needs oiling and cleaning. Does it die at idle only or at any rpm? I need some details on how it runs when it runs.

 

[mjdavis31]

:shiver: :shiver: :gonnablow i also have a problem with no start/took my toy for a short ride .shut it off for 10 minutes tried and wouldnt start.no power to coil,so i changed crank sensor/still nothing!!!so i tried ign switch/still nothing called local dealer and they said computer/well still nothing!!.i disconnected battery for a overnight charge /just for fun i reconnected battery and turned the key...and it started and ran for 30-40 seconds and quit####i have done this about six times with same results.PLEASE HELP///TIME TO FIX IT OR SHOOT IT!!!!!!!!thanx /vinnie 92xj 4.0 auto 4wd

:rof: throtle position sens.

 

[xj2win]

I can clean the IAC etc no problem, I have no trouble working on cars, it just helps when I know what the problem is! What is the CTS sensor?, I'm not familiar. Tested the MAP sensor and it's fine. It's also possible that there was condensation in the injectors that froze, or some other sensor could have frozen up I suppose. My brother in law said a lot of times the ranch trucks will run rough when it gets really cold and blizzards like that, there was a decent amount of snow blown up into the engine bay. I guess I'll try and start it without WOT when I go back next weekend, and work from there.

 

[Ecomike]

CTS = Coolant Temperature Sensor

 

[truck2hi2cu]

i thought maybe had a bad cps that i bought and changed it again/still after started it died and didnt restart.i have fuel but no spark.changed cps computer,ign switch,coil,cap and rotor..........checked all fuses,ballast resistor,relays,wiring..........please if someone has a suggestion i would love to hear from you ,i have put too much time and money to not be able to enjoy my 92xj 4.0 auto 4wd

 

[CrawlingCritter]

Some of the above is not correct. The engine can start and run with the O2 sensor disconnected, or even dead. The ECU does not use the O2 sensor during engine warm up.

Just going by Ye Olde Renix Ignition Training Book. You're right, it didn't say the engine wouldn't run, just that the ECU uses input from the O2 sensor to set proper air/fuel mixture. Should have read slower. aperwork

 

[CrawlingCritter]

Has anyone ever had to replace an ECU?:rattle:

 

[Ed in North Ga.]

When I was here a few years back, there was a few ECUs replaced-
but i do remember someone finding out that in renix era ECUs, it ended up being something simple that just needed a little re-solder to bring it back to life-

recently, I havent heard of any failures- in a long time.

 

[Ed in North Ga.]

i thought maybe had a bad cps that i bought and changed it again/still after started it died and didnt restart.i have fuel but no spark.changed cps computer,ign switch,coil,cap and rotor..........checked all fuses,ballast resistor,relays,wiring..........please if someone has a suggestion i would love to hear from you ,i have put too much time and money to not be able to enjoy my 92xj 4.0 auto 4wd

you changed the CPS, but did you test it with an ohms meter?
theres two *main* things that make the spark that we check first- The CPS (and the RPMs needed to wake it up) and the ignition- gets harder from there, but we rarely go that far-

actually, any time mine did a start, then die, then not restart, it was the IAC motor stuck in- it wouldnt let enough air into the throttlebody-

 

[Ecomike]

Has anyone ever had to replace an ECU?:rattle:

Short of tossing them into a fire or metal crusher, they are indestructable, ask me how I know!!!!!

Have you tried the suggestions we already made? i.e. IAC, clean and lube it? Do an ohms test of the 2 temperature sensors? All easy, cheap common causes of your problem.

 

[MoparManiac]

Sorry but I have to ask...how do you know?? lol

 

[Ecomike]

Sorry but I have to ask...how do you know?? lol

Ah, someones curious, they say resistance is futile!

I hooked up two sensors backwards to the ECU, the TPS and the O2 sensor, shoving the full 14 volt alternator voltage into the 0 to 5 volt input of the ECU. Never phased it. It still works perfectly. I must admit, I have not tried connecting the HV coil output to the ECU inputs yet, LOL.

 

[XJPhoenix]

Slightly off-topic, but how does one go about cleaning and lubing the IAC?