Ok guys, yall aint let me down yet. I need some help ASAP. Drove my 94 ZJ into work (92 XJ motor), it misses and skips anywhere above ~2500 rpms, still dont know why. About 30 minutes in, I noticed a new problem, I felt a slight buck when I was going up a hill. Then after a few more minutes it got progressively worse. by the time I parked at work, it was skipping and bucking just idling through the parking lot. Im an hour from home and my shop, I at least need to make it home, I have a ride this weekend that I am supposed to help run, a jeep kinda helps there as well. Thanks in advance for yalls help.


Pic just because I love my rig, even if she is a *****!!!

 

I'm going to go with check your fuel pressure first.

 

I checked the fuel pressure a couple weeks ago and it was good. but Ill check it again

 

Checked the codes. Threw a code 17. Engine did not reach operating temperature in acceptable time. I noticed it's been running really cool (180)

 

Only mentioned fuel pressure cuz it's quick n easy and some of the symptoms and conditions apply...

Looks like something in your coolant circuit is wonky. When is the last time you changed the t-stat and coolant?

 

Yea, if I can get to parts store ill test it. Thermostat I have no clue, it was in the motor when I put it in. Coolant was just a few weeks ago when I put in the new motor.

 

Understood. Prolly oughtta get a Mopar stat in there ASAP and go from there. May not be the end of the issue.

Keep us posted.

 

Put a new TPS on it for good measure on my lunch. Didnt have time to do the t stat. Hopefully I can at least get it home... Any thoughts before I try and get it home?

 

Hey JSJJ388,

I doubt that the TPS is at issue and, in fact, if the one you just added is not Mopar then you may soon get a new problem. So keep the old one safe for now because it was working and you may need to restore it.

Did you use a 50/50 coolant solution or was it almost pure coolant? (I find the 50/50 premixed solution best/easiest as I change my coolant annually.)

With an OBD1 code 17, a stuck-open or missing T-stat might be the issue but since you can't be absolutely sure on status of the one in the donor motor then it's prob'ly a smart move to drop in a new Stant 195 T-Stat.

Also take a few minutes to test the resistance of the coolant temperature sensor (not the thermometer for the dash gauge). If at typical warm engine operating temperatures then you can expect to measure a resistance value in the range of 1k ohms and if at ambient air temperature (like 77 degrees) then expect a value near 10k ohms.

Don't dis' your rig. I think it's awesome. Have a great ride this weekend and keep the faded, scratched, dented and painted side up.

...and Happy Independence Day too! WooHoo!

 

Thanks, I replaced the TPS for two reasons. 1) It has acted up before, and 2) it fit the symptoms so I tried it. I will try and test the sensors this weekend. Im not going to be able to make the ride though.

Im not dis ing it lol, shes just being a ***** right now, but I still love her lol

 

Too bad you're stuck. On one hand, if you stay around then you'll have more time to take care of details. On the other hand, you'll be alone while all your buds are out playing and that's depressing. Why can't you go with a pal as a (gulp!) passenger?

If all the other stuff we talked about doesn't help then you may as well start looking for a vacuum leak. That too could make it skip, buck and limit RPMs...