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Need Help Quick!!!

94XJ2door5speed

94XJ2door5speed

NAXJA Forum User
Location
Norwich, CT
I decided to replace my fuel filter today to see if that was the culprit for the skip. MADE IT WORSE!:flamemad: like not driveable worse. I unplugged and replugged the O2 sensor in because it made it stop skipping last time for about 20 min. It made it driveable but it changed everything even stuff it shouldn't like the way my clutch grabs? It is way worse than before i replaced the filter and the skip is still there right at 1800 to 2100 like it waits to get there then skips no matter what, i cannot avoid it does it no matter when it passes it going up or down im ready to give the jeep away and go back to my FORD.
1994 4.0L AX15 NP231 d30/8.25 Ran great for a day when i bought it then the crank sensor died and ever sense this nightmare. Replaced absoluley everything but the coil but that wouldn't make it only skip at between those rmp's
NEED THIS THING FOR CLASS ON MONDAY!
 
wow dude, take a deep breath....

what all have you replaced? did you replace your TPS and Idle Air Control? did you replace your O2 sensor, or just unplug it and plug it back in?
 
I had a skip sputter stumble.
Cleaned spark plugs, wires, dist, ig primary wire and added di-electric to all wire connections and checked TPS.

I suggest you do the same.
Replaced absoluley everything but the coil but that wouldn't make it only skip at between those rmp's
Click to expand...
That tells a lot, NOT
I'd suspect TPS from given info, check it with an anolog volt meter to find "dead spot" in sensor range
 
This is one of your posts from 6 days ago..

"Well lets see no CEL. no codes found. replaced ready for this, cap, rotor, plugs, wires, TPS, crankPS, camPS, O2 sensor, fuel filter, ignition coil, tested my computer in another jeep ran fine. Fuel pump is good. The jeep ran great when i bought it ok. Got home turned it off. Woke up the next morning it wouldnt start no spark. So i did full tune up theres the list of stuff i replaced. Ever since then it has skipped, it didn't before only after that stuff was replaced. Only thought is that there was crud in the tank and it plugged the new filter almost instantly. So now i pay closer attention and it is really only when it is under a load so i'm thinking fuel delivery, have ran 6 different types of fuel system cleaner since i bought it cause it sat for 11 month bofore i came along and bought it. I also replaced front axle u-joints tranns mount, motor mounts, sway bar bushings, rear output seal on t-case and front calipers and rotors. Those won't affect the motor though. Can't find a vacuum leak either, I do have a cracked manifold but don't know if that will affect it. Thought the jeep was a steal at $800 but not so sure now. I'm gonna try another fuel filter when its not 10 degrees out even thought its only got 1,500 miles on it."


Something went wrong when you changed all this stuff...maybe you got a bad spark plug, wire(s) or you accidentally crossed some plug wires..
it's time to retrace your steps...if you have all the old parts, consider putting them back in, one at a time... and try your Jeep out each step of the way.
 
Yeah ok well when i say everything i mean everything!!! The tps, distrubutor, cap, roto, cam sensor, crank sensor, plugs, wires, fuel filter, O2 sensor, checked my computer with another guys it still skipped, vacuum lines. The idle air control wouldn't affect that according to the Tech i spoked too. don't know what else but stop suggesting the TPS thats all everyone has told me. I have tested it with 3 different kind of meters and an o-scope it is fine same with the crank and cam sensor. I am lost though maybe timing not sure.
 
McQue said:
This is one of your posts from 6 days ago..

"Well lets see no CEL. no codes found. replaced ready for this, cap, rotor, plugs, wires, TPS, crankPS, camPS, O2 sensor, fuel filter, ignition coil, tested my computer in another jeep ran fine. Fuel pump is good. The jeep ran great when i bought it ok. Got home turned it off. Woke up the next morning it wouldnt start no spark. So i did full tune up theres the list of stuff i replaced. Ever since then it has skipped, it didn't before only after that stuff was replaced. Only thought is that there was crud in the tank and it plugged the new filter almost instantly. So now i pay closer attention and it is really only when it is under a load so i'm thinking fuel delivery, have ran 6 different types of fuel system cleaner since i bought it cause it sat for 11 month bofore i came along and bought it. I also replaced front axle u-joints tranns mount, motor mounts, sway bar bushings, rear output seal on t-case and front calipers and rotors. Those won't affect the motor though. Can't find a vacuum leak either, I do have a cracked manifold but don't know if that will affect it. Thought the jeep was a steal at $800 but not so sure now. I'm gonna try another fuel filter when its not 10 degrees out even thought its only got 1,500 miles on it."


Something went wrong when you changed all this stuff...maybe you got a bad spark plug, wire(s) or you accidentally crossed some plug wires..
it's time to retrace your steps...if you have all the old parts, consider putting them back in, one at a time... and try your Jeep out each step of the way.
Click to expand...

Thought of that dude, put new new wires and a new new cap and a new new rotor same effects. I no longer am in CT no original parts.
 
Cracked manifold can cause other problems. O2 misreading due to lost exhaust gasses, mine ran rich and burned out my Catalytic converter.
 
where are you in pa? if your near me i might be able to help.

your one post says you replaced the distributor, its easy to be one took off and for it to start but run bad under load.
 
I was going to suggest that you check compression, but reread your list and note that it skipped after you did your tuneup.

If it skips under load and does not throw a code, recheck the ignition. Even though you replaced everything, this is no guarantee that something was not just defective. Check the plugs, and check the wires for continuity and make sure they're really properly seated on the plugs. It's sometimes too easy to insert the angled ones at cylinder 1 & 6 without actually getting the wire clips over the plugs. You would not be the first person to get a bum plug or wire out of the box. It's rare but it happens, and when it does, it's often the last thing you consider. You also need to make absolutely sure that you got the firing order right, and that there is no defect in the distributor cap. Make sure the little carbon button in the top is in place and contacting the rotor. I'm betting that if the skip arose after you did your tuneup, you'll find your problem somewhere in the tuneup parts.
 
89xj said:
where are you in pa? if your near me i might be able to help.

your one post says you replaced the distributor, its easy to be one took off and for it to start but run bad under load.
Click to expand...

I'm in Indiana PA and thank you guys alot, with the injectors though, why would it only be at this very very specific rpm this is what boggles my mind. It is so on time i know exactly when its going to happen my friends think its hilarious. We will take off and i wll be like 1st... skip, shift to 2nd wait for it wait for it skip, shift to 3rd o o o here it comes skip, you get the idea. Its like the computer is missing something at the exact second or rpm and once it is passed it is fine again. Get it loaded down going up a hill right at 2 grand and you could stick a yoohoo on the dash and it would be well shaken but the time you got to the top.
 
94XJ2door5speed said:
I'm in Indiana PA and thank you guys alot, with the injectors though, why would it only be at this very very specific rpm this is what boggles my mind. It is so on time i know exactly when its going to happen my friends think its hilarious. We will take off and i wll be like 1st... skip, shift to 2nd wait for it wait for it skip, shift to 3rd o o o here it comes skip, you get the idea. Its like the computer is missing something at the exact second or rpm and once it is passed it is fine again. Get it loaded down going up a hill right at 2 grand and you could stick a yoohoo on the dash and it would be well shaken but the time you got to the top.
Click to expand...
Still sounds like an ignition fault to me. That's where I'd start.

Get a vacuum gauge and a long hose. If it pulsates or wobbles at idle when it's not actually missing, look for a bad valve or other compression problem.If not, then.....

Hook said gauge to the intake manifold or a manifold-fed line that is not interrupted by any valves or devices, and tape the gauge to your outside mirror. Now drive. If the gauge jitters or pulsates when it starts to miss, look for ignition first, mechanical second. If the gauge does not jitter (or does so very little) when it starts to miss, look for fuel injection problems.
 
Mine is an 88 MJ and does exactly the same thing in the same RPM range. Interestingly enough, it does NOT skip when it has a heavy load in the bed. I have done/changed all the same things that you have with no improvement.

On another post awhile back, someone suggested a small manifold leak that hits the O2 sensor with a shot of fresh air and fools it momentarily, causing the skip....that makes sense to me, and I'm gonna check that out.

I still cannot understand why it ONLY happens in that specific RPM range tho.

stay with it and keep us posted, inquiring minds want to know......
 
Can you break torque it and make it skip setting still? If so, have someone break torque it for you while you pull each spark plug wire one by one to see if it's a particular cylinder causing the skip.
 
Jed said:
Can you break torque it and make it skip setting still? If so, have someone break torque it for you while you pull each spark plug wire one by one to see if it's a particular cylinder causing the skip.
Click to expand...

Not sure if that is possible in a 5 speed or not? As to the vacuum guage idea i will have to try that. Last night when it was idleing in the parking lot it does have a very slight miss almost not noticible unless you are really looking for it. Then i held it at 1500rpm sitting still and the skip was very noticible and again right at 2000rpm but at 2100rpm nothing, runs real smooth.
 
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