paying 300 for some one to fix this xj

mossyOblack

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hickory/newton
DIDN'T SEE A SERVICES SECTION SO I FIGURED THIS WAS THE BEST SPOT MODS PLEASE MOVE IF NOT CORRECT



Mossy
Newton nc
Pm or post here
98 xj 4.0





Ok hers the deal.. 98 xj had a blown motor.. Bought a 92 parts jeep and took out the motor.. Pretty much just the long block... Swapped it in the 98 with the intake manifold and sensors from the old 98 motor... Also used the cps from the 98... Motor starts idles then dies unless depressing the accelerator.. And even then it misses and back fires... I've changed plugs... Cps.. Injectors.. Wiring harness.. Map... And still the same issue.. I'm willing to pay upto 300 dollars in labor for a completed job.. I've had several mechanics come over and bs me.. Have me buy a ton of parts and still won't run.. Then they expect to be compensated... I will only pay for a COMPLETED job... I will buy parts.. Not interested in having it towed away to someone garage... I have a few tools here but you will need to bring your tools and diagnostic gear... please contact me asap like have her running before first snow...

The motor from the 92 was running just fine.. When it was pulled... It was pulled and dropped in the same day...
 
i guess u used the original throttle body and tps? have you checked all the grounds?
 
Yes used the 98 manifold... With the throttle body... Would a ground let the car run? Doesn't make much since to me if it will start and run if I keep my foot on the gas...
 
No cels a few popped up as we were unplugGing sensors looking for changes in the situation but no cels....



What vacuums would be best to check? Ive checked the one right under the map sensor...
 
If you can keep it running with the throttle, try driving it around for 15-20 mins. My 99 didn't want to idle after the battery died, was told the computer had to relearn idle, etc. drove it around for awhile and it was good to go.
 
Clogged cat? Vacuum leak? Cps on the transmission bellhousing? I've had all three cause the problems you're describing on an xj. What you didn't say is what about the coil and distributor, were they swapped from the old engine? Vacuum leak sounds fairly obvious since you did swap the intake manifold...
 
untchabl said:
If you can keep it running with the throttle, try driving it around for 15-20 mins. My 99 didn't want to idle after the battery died, was told the computer had to relearn idle, etc. drove it around for awhile and it was good to go.
Click to expand...

I just did a head job on a 97. Sounds like the same thing it was doing... have you tried to sit in it for 20 or 30 min holding the gas? I had to do it 2 or 3 times before mine would idle. Your computer needs to relearn to idle I'd bet.
 
I'd sit in it and keep it running for 20 mins or so. Try that a few times before you throw anymore parts at it, won't cost anything but time.
 
Have you made sure the plug wires are in the right order, also the injector wires. Sounds silly but I helped a buddy after he put his in and it did the same thing, it was just the wires mixed up...
 
Sounds to me like the distributor is off a tooth one direction. Mine did the same thing when I swapped out the dist a while back.
 
sounds like a loose ground to me check them all & make sure they are all tight (seem it more then 1 time ) there is one on the pass side near the back of the block that one gets over look all the time
 
Sounds like a weak battery to me. Leave it on a charger overnight, and then try to crank it. Jeep somehow designed the 4.0's to not idle with a weak battery if the battery had been disconnected. It will only crank and idle if the battery has a good charge, or at least if the computer thinks it has more than 12 volts.
 
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