'89 Pioneer - Now what?

[Jeepguy91]

Truck looks good. I've used that Goof off stuff before and it worked for me to. Seems like your plane is always finding new places to crash at. Trees, pickup beds, whats next?

 

[Lowrange2]

Truck looks good. I've used that Goof off stuff before and it worked for me to. Seems like your plane is always finding new places to crash at. Trees, pickup beds, whats next?

One day I'd like to land it peacefully on a runway. lol

 

[87manche]

smooth as glass

 

[Happytrails]

Renix? TPS is always suspect. Can't recall how many times I place the thing on my 1990 XJ. Just got used to it and learned how to set it right with the multimeter.

 

[Lowrange2]

Thanks. I still haven't fooled with it. Just been driving the truck back and forth to the trash dump.

 

[Lowrange2]

Swapped out the TPS last night, finally.

Still no change. It's doing the exact same thing...

Makes NO sense. It ONLY does it when throttle is in that certain spot.

 

[Lowrange2]

was once a busy place. lol

Looks like Facebook has almost completely taken over.

I'll go ask for help there.

 

[831_xj]

Maybe I missed it.. But what's it doing?

 

[Lowrange2]

The engine starts misfiring when the pedal is in a certain position. I can make it do it on demand. When I put the pedal in the "Sweet Spot" to maintain any speed is does it. Feels like it's misfiring 2 or more cylinders randomly. As soon as I push the pedal harder or let off it runs slick as a button. Go back to that same spot and runs like crap. Doesn't matter if the engine is under load or not. Doesn't matter what speed.

I've cleaned all the grounds
Replaced the TPS
Tested and adjusted the TPS
And replaced the CPS (Due to another issue)

 

[MT Mike]

Have you checked fuel pressure in this "sweet spot"? I had something similar happen with my 89 XJ, turned out the short piece of gas line from the pick up tube to the fuel pump (inside the tank) was rotten and allowing fuel pressure to bleed off. Might be worth checking.

 

[Lowrange2]

I haven't checked it. and I will but that doesn't make sense. It takes WOT just fine. It's definitely related to the TPS somehow because when I adjusted the TPS it moved the place that it starts to miss.

 

[IllianaXJ]

Try a different throttle body? Maybe the TPS location is ovalled out causing it to read wrong?

 

[Lowrange2]

It seemed to be running through the range smoothly from .83v to 4.9v @ WOT.

 

[831_xj]

Diz cap? I had a renix did something similar and I pulled my hair for weeks. Turns out the dis cap was chipped and would skip one if I hit the throttle just right. Can you feather the throttle at idle to get it to stumble? If so, can you smell fuel?

 

[Lowrange2]

All of that has been replaced recently by the PO. I'll take a closer look at it.

 

[XJCasper]

Skipping some reading. Check your O2 sensor? Not sure if 89 has one or two.
Your descriptions sounds similar to when my primary O2 sensor was getting hit my the driveshaft. Visual inspection established that issue.

 

[Lowrange2]

I'll give it a look.

I was told to replace the injectors so I have some of those on the way to try.

 

[XJCasper]

I'll give it a look.

I was told to replace the injectors so I have some of those on the way to try.

Ya, my current issue is different than yours. Son found an injector leaking. Still not sure what injectors I want to switch to, so gonna grab some new o-rings.

 

[Lowrange2]

I'm just swapping in some known good used ones for now.

 

[Demonoid369]

any luck? id look for shorted or broken wires and check the grounds. i know i had issues with my 97' trying to get spark. turned out the wires going to the ignition coil had a break in it so that if you moved the wires you could make it fire and not fire.