• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Erratic idling

yeah, the wire does NOT get wet with antifreeze, water, blood or anything else. I'll wrap it up nice and tight when i get home.
 
Gotcha .. I'll give it an extra look. IIRC, it's pretty oil soaked.

I imagine this is a task best to do by hand, and leave the degreaser at home?
 
I just went out and took some pictures ... in the process of scanning them, I realized that I think some of the fuses are wrong.

For example "HAZ/STOP 15" has a 25 fuse in it. Other than being dangerous, could this be a possible culprit for poor idling or parking light/blinkers issues?
 
So I went out and replaced all the fuses with the proper rating. No change in the idling nor in the weird blinker issue.
 
bigalpha said:
I just went out and took some pictures ... in the process of scanning them, I realized that I think some of the fuses are wrong.

For example "HAZ/STOP 15" has a 25 fuse in it. Other than being dangerous, could this be a possible culprit for poor idling or parking light/blinkers issues?
Click to expand...

No, but who ever increased the fuse size did it for a reason, a short. Try checking the wiring on those services.

Blinker issues?

Have we discussed all the grounds, and how important, and how notorious they are in 87-90 Renix jeeps?
 
Last edited:
Hey have you checked your CPS? I had one go bad and cause my jeep to sounc like it was hunting cause the wires got too much heat from the manifold. If you disconnect it at the fire wall connection you should have 200 Ohms +/- 75 Ohms. Alternately you should have about the same reading at D1 and C1 of the input to the ECU if you wanted to check for your harness as well. There was a service bulletin released to correct the harness issue as well.
 
Ecomike - I'll take a look and try to trace as much wiring as I can. From what I can tell from digging around under the hood, all the wiring looks to be alright. There are a few disco'd wires but I assume that they're like that b/c of features I don't have. Also, here is my blinker issue thread: Weird symptoms ... related?

Stihl - I have not checked the CPS. It didn't occur to me since I don't have any issues with starting. I'll do a little searching and test the CPS connection. Where's the connection for the ECU?
 
Also, I unplugged the IACV with the engine running and it didn't affect the idle speed much even when I plugged it back in.

When I unplugged the TPS and hit the gas, it just revved up until I plugged it back in; then it would kind of correct itself after I hit the gas.
 
Why don't you start a new thread on your blinkers? I don't understand the single/dual filament thing in your Commanche thread. Dual filament bulbs have two electrical contact posts at the bottom of the bulb and offset little pins on the side that hold them in the socket. Single filament have one electrical contact post and the retaining pins are the same height. To put one in the other, you have to file off the post or JAM the bulb into the socket. I doubt that the blinkers and idle are related.
 
In a nutshell, I didn't understand why the front blinkers needed dual-filament bulbs; mine only light up when the blinker is used, and are not on as 'running lights'. The tall corner lights light up with the headlights, though.

My thoughts were maybe there may be some weird short in the system causing hell with the idle and playing hooky with the lights.
 
Sounds like a grounding problem.
 
I've checked all engine bay grounds and the taillight ground and all test less than .5ohms (uncorrected; .3 or lower corrected).
 
Still no progress on the idling issue. I tightened the manifold bolts (a few were slightly loose) and that evened out the idle just a hair.

Unplugging/plugging in the IACV while the Jeep is running didn't change anything; same with the TPS.

Still idles at about 1500 in P and N; will slowly rev up to ~3k RPM and maybe bounce around a bit. Hitting the gas doesn't always bring it down.

I replaced the IACV and TPS already with no change in idling speed. Could a dirty TB cause this issue, even if the IACV is clean? I could cover up the IACV hole and the engine would idle down to about the right RPM.

What's weird is that when cold, I start it and shift into R and the truck will die but it restarts immediately.
 
bigalpha said:
Still no progress on the idling issue. I tightened the manifold bolts (a few were slightly loose) and that evened out the idle just a hair.

Unplugging/plugging in the IACV while the Jeep is running didn't change anything; same with the TPS.

Still idles at about 1500 in P and N; will slowly rev up to ~3k RPM and maybe bounce around a bit. Hitting the gas doesn't always bring it down.

I replaced the IACV and TPS already with no change in idling speed. Could a dirty TB cause this issue, even if the IACV is clean? I could cover up the IACV hole and the engine would idle down to about the right RPM.

What's weird is that when cold, I start it and shift into R and the truck will die but it restarts immediately.
Click to expand...


You have a large, or multiple small vacuum leaks. At 1500 rpm the TC does not slip enough in reverse, with brakes at applied at 1500 rpm it kills the engine, that is normal. May be time for a new manifold gasket. Also check the throttle body gasket. Try a bottle propane to feed the vacuum leak as you hunt for it, engine rpm will go up when the propane sees the leak.

Lots of vacuum lines even in the front bumper to the hidden vac bottle!
 
Is there a schematic floating around that shows all of the vacuum lines on a RENIX engine? I tried searching but didn't find one.

I thought the vacuum situation was all buttoned up; but apparently not. The one suggestion that makes me cringe is having to replace the manifold gasket.

Since it revs stupid high in P and N; can I have someone on the brake with the tranny in D or R?
 
You must log in or register to reply here.

Similar threads

I
High idle, smells like gas, running out of things to replace
Replies
2
Views
2K
Inverhyt
I
I
Bumpy Idle, ways to narrow it down?
Replies
6
Views
122
my2monkeys
my2monkeys
F
Stumped on this one!
2
Replies
29
Views
4K
Bent
Bent
J
AW4 Problem shifting first to second when hot
Replies
2
Views
1K
cruiser54
C
P
2K IDLE - Odd Shifting - TPS? (I know.. I know)
Replies
3
Views
2K
Unclewolverine
U
Back
Top