Absolutely check this first. been through it 2 times.

 

Does your Check Engine light work? By that, I mean that it will light up when you have just turned the key 'on', but before you have actually cranked the engine over. That's the light bulb test for the dash.

Since it's a '92, you should be able to turn the ignition key On-Off-On-Off-On, and the Check Engine light will blink out any fault code numbers stored in the Powertrain Control Module.

Just did this on my son's '91. Are you familiar with this test? Do you have a shop manual with you?

I don't know if it's true for a Jeep, but on many cars I've worked on, there is no fault code set if the Crankshaft Position Sensor fails.

No codes stored tells you that a whole lot is RIGHT with your engine - valuable information in itself.

A few of the codes off the top of my head are: 12 = battery disconnected and memory erased in the last 50 - 100 starts, 24 = Throttle Position Sensor voltage too low or too high (usually a trashed sensor, as it was in my case), 55 = End of test.

Keep us posted!
Dan

 

Other things it could be besides CPS are:
Check the cap/rotor. its 2 phillips screws pops right off. make sure the rotor that spins around has no corrosion on it as well as the cap. make sure its on tight when u re-install it.
Battery connection? Grounds maybe? Does it turn over?
Its probably the CPS. sometimes the wires can melt from the ehxuast and they will cause the circuit to short out. Leave the battery disconnected while you are replacing your CPS. (Crank position sensor) Its a pain in the butt to change, I would advise doing it in a garage with heat, many ratchet extensions and a good flashlight. get a friend to help hold the flashlight also.

 

if its turning over the cps would be a good place to start checking

 

First try to test the connection before you replace the CPS because it's a ?!@&$. That happened to mine and I just wiggled it and it came right back to life

 

As the other 12 before me have mentioned, the crankshaft position sensor is very suspect.

IMHO, it is the #1 sensor failure on the Jeep 4.0

Here is a link to a thread that gets into this in more detail, along with TESTING, which is something you should do before replacing. Good luck and check back and update us with what you found!

http://www.jeepforum.com/forum/f11/c...ailing-639123/

 

X2 on checking the codes thrown by computer. I used the check engine light method that someone posted earlier and it works. For me, it did flash out the code for CPS. Saved me a lot of time and money. CPS is a bear to change. I have a 1993 XJ.

 

Forgot to mention...make sure your check engine works first before trying to get the codes!! The previous owner of my XJ had taken the bulb out! So I had to fix that first and then get the codes.

 

man, wish i was a girl...then i could get 2 pages of replies in less than 12 hours when i have an issue

just playin,

i had my CPS go out in my 98....randomly would shut off (mid-driving), sometimes would start right up, sometimes it'd take multiple cranks, sometimes wouldnt do it for a day or so, sometimes would do it 590 times a day, till i finally changed it.....& i didnt think it was that much of a PITA, just slid under there with a strap on (flashlight) on my forehead, 2 little bolts, new one went in.....only thing i found to be a PITA, was ~$100 for a little electromagnet sensor with about a foot or so wire.

anywho, welcome & good luck

 

it must be the crankshift sensor, because it once the same thing happened with me and it was the crankshift sensor
goodluck

 

just had same problem have battery tested for any dead cells, that and a new rotor button fixed it.

 

Spray some starting fluid in the intake hose or directly into the throttle body... doesn't take alot... 2 second hit.. if it starts then it is a fuel problem... probly fuel pump... if it does not start it is electrical... do this test and get back with us...

 

Its not a battery lol...

 

What a jerk.

 

Do you remember what code it flashed? I looked through my Chilton's to see if there was one listed for the CKP, either I missed it or the manual isn't perfect.

Could be putting in 62+ hours this week at work (so far) that I wasn't sharp enough to catch it.