• NAXJA is having its 19th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • 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.

1987 Renix High Idle Issue

I think what I could use, is a video of someone's Renix running in closed loop in Park, and having them scroll through all the sensors in their Renix Engine Monitor so I can see how theirs looks, that way I can compare it to mine and see if anything is off. That would be of immense help.
 
Got a video from a friend. Only thing I really noticed is that my O2 sensor is a teensy bit slower, and that my STFT is different. In gear (idling around 850rpm), my STFT swings between 90-115. In Park/Neutral (idling between 1000-1100), my STFT swings between 110-130. Does this information tell anyone anything?
 
Alrighty folks, I think this might be a wrap. Since I've literally tried EVERYTHING... I decided to finally adjust the butterfly stop screw, and it brought the idle down!!! I guess the thing was just taking in too much air through the butterfly?

I took my original throttle body, I shined a light through it and re-centered the butterfly with a feeler gauge. I kept shining the light and closed the butterfly as much as I could with the throttle stop screw and brought it back out a little. Instead of having a .003" gap l, I brought it down to maybe roughly .0015" or .002".

Was adjusting the stop screw the correct thing to do? Maybe.. I've tried just about everything. IAC, TPS, intake gasket, a different TB, all my vacuum lines, deleted C101, fixed sensor grounds, smoke tested by myself and a shop, replaced the EGR, MAP sensor, MAP sensor line, O2 sensor, ECU, and probably a lot more. I probably need to touch the 'adjustment' up a bit more, likely the idle bleed screw, but it's much better. There still seems to be a 100-150rpm-ish difference between P/N and gear, but good enough I suppose.

Unfortunately for the crazy part. When driving it the other night. I braked pretty hard for a stop, and I heard what sounded like a bag of rocks under me. Turns out my NP242 transfer case took a dump.. What good timing.. I'll be having it repaired. I don't think the transfer case was taken care of that well, when I did the fluid last year, only about a quart of old black oil came out. It's possibly never been done before. When I inherited it, I was also told that supposedly the 4wd didn't work. So there's that.. All the chickens coming home to roost.
 
Sounds reasonable to me...too much air? Block the air. You definitely hit all the "right" ways to do that first.

I never really understood the feeler gauge method, I thought the goal was to turn the butterfly until you saw the smallest amount of movement (so it wasn't bound in the bore at zero throttle).

Sucks about the TC.

Edit: that RPM difference between P/N and in gear is normal, I believe - just resistance from the torque converter. At any rate, mine has the exact same drop.
 
Last edited:
Sounds reasonable to me...too much air? Block the air. You definitely hit all the "right" ways to do that first.

I never really understood the feeler gauge method, I thought the goal was to turn the butterfly until you saw the smallest amount of movement (so it wasn't bound in the bore at zero throttle).

Sucks about the TC.
Looking back, I agree the feeler gauge method of determining the gap might be a bit questionable or outright incorrect. Also yes, the transfer case is a huge bummer, but I ain't giving up on it.

I'd like to thank everyone who's helped out in this thread, especially mewz. When I turn 21 next year, I owe you a beer!
 
I decided to finally adjust the butterfly stop screw,
At the risk of sounding like an idiot, where might that be located? I suppose I could look in the FSM; but since we're here...
 
where might that be located
It's right where the arm of the butterfly connects to the throttle cable(s). The arrow points to an opening containing the head of the screw, you can see the threads poking out the other side to set the minimum position for the butterfly.

look in the FSM
I've looked, and I haven't found anything in the FSM detailing this or the idle adjustment screw. Rather annoying.
 

Attachments

  • butterflystopscrew.png
    butterflystopscrew.png
    227 KB · Views: 5
Back
Top