High Idle & AW4 problems: FIXED

Spent the last couple of evenings reading AW4 threads on slipping and shifting problems. I hope its just the TPS and a cable adjustment. Did the shifter cable adjustment tonight. I will know for sure tomorrow when I swap in a new (used known good) TPS out of my Ramblers stroker motor.

Symptoms:
Over the last couple of months I have had to back off the throttle to get it to up shift. Over time I have had to go higher and higher in rpm before the shift would occur. This was not really a problem just an annoyance. It would shift in the 2000-2300 rpm range when I let off, maybe 3000 rpm if I didnt let off. I had all 4 gears. Idle was steady at about 700 rpm.

5 days ago I started it up and it suddenly idled at 1700rpm and wouldnt settle down to a proper idle until after about 30 minutes of driving. The next day it started, idled and drove just fine on the way to work (still having to let off I wanted it to shift 2000-2300rpm). Later that day on the way to a meeting (the high idle was back) it wouldnt shift out of first into second until I let off at 3000 rpm. Once it shifted to second it took just the slightes grade and lightest pressure on the throttle to make it down shift. After the meetingt I went straight home on back roads and it took more and more rpm to shift, not shifting until I let off at 4000 rpm. I havent seen 3rd or 4th gear in the last 5 days.

Fluid level is good. Fluid is red and smells fine. I have always run a big trans cooler.
Unplugged TCU and tried to shift manually all I got was a lot of slipping in first and second gear with no power to the wheels until about 2500 rpm in first.

245,000 miles, 4.0, 31" tires, 3.54 gears.

If its not the TPS or if the TPS fixes the idle but not the shifting, then I am guessing its solenoids sticking.

Update tomorow after the new tps is in.

John

Re: High Idle & AW4 problems

Sure sounds like a TPS issue, along with a TV cable adjustment (maybe). But first check your tranny grounds, TCU ground, your TPS ground and the ground behind the kick panel and/or near the lower dash brace.

I'm not exactly sure how the grounds interact, but my radio lights used to blink when I shifted to reverse and I'd often need 2000 RPM for shift. I just refreshed every ground I could find and the issues disappeared. I'm not exactly sure which ground was causing the issues, I just refreshed them all. I also cleaned some of my connectors, which may or may not have been a factor. I never did have a high idle though, which makes me think what you have is a TPS issue, then again you may have multiple issues.

Re: High Idle & AW4 problems

8Mud,

Thank you for the grounds suggestion. I did not get the new TPS installed. I spent the entire day running from DC to Richmond visiting every PnP to find good front end parts for my Altima daily driver (deer committed suicide last week.

I did score an AC delete bracket and found two TPS units. XJ's are getting real hard to find around here.

TDY for a few days so no update til next weekend.

John

Re: High Idle & AW4 problems

Darned Deer walked out in front of me the other morning (0300 hrs.) dark as heck, street wet from a recent rain. I'm old and about half night blind, I didn't see that sucker amble out in front of me until the dogs started barking LOL. I got stopped in time, but that darned Deer refused to move, flashed my lights, honked my horn. I really thought I was going to have to get out and give it a boot in the rear to get it to move. It finally gave me a look of disdain and walked on across the road. If I would have been driving my XJ I would have turned it into road kill, but I was driving the wifes and thought I had better not.

Re: High Idle & AW4 problems

nosigma said:

Unplugged TCU and tried to shift manually all I got was a lot of slipping in first and second gear with no power to the wheels until about 2500 rpm in first.

Click to expand...

Sounds like internal transmission problems or your torque converter has gone south.

Re: High Idle & AW4 problems

Installed the new TPS tonight. Shifts great, all the problems are GONE. The fix cost me nothing but gas and a little search time on the OEM tech forum. The pick and pull cashier gave me the TPS for free.

I LOVE that search button.

8Mud: Got ya on the deer. I live inside the beltway, very urban just outside Washington DC . Deer come up a creek from the Potomac River and run all over the neighborhood. Walk down the streets in daylight and block traffic. Had a group of 5 laying in the back yard. Our dog ran out (beagle/rottie mix) to drive them off. A couple stood up, most stayed down. He nipped some hind quarters and got a kick in the face. Distrubed him greatly. Deer didnt leave. Dog ran around barking and growling, deer didnt care one bit.

John