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Low output voltage on tps.

Rushin said:
Tested continuity between D7 and the chassis and the voltmeter chimed fine, no breaks. I have been cleaning all the connections under the hood and noticed a stray connector. It is just one black wire. Looks like a ground wire or something. Will post a picture in a second.
3f4e7a83.jpg


Any idea what that is?
Click to expand...

btw, this is a cruise control ground wire.
 
Rushin said:
so cutting onto the tps ground wire?yes, and running it to a good ground I kind of did this. I just put a an extra wire into the plug where the tps plugs to the tps harness. What i got was a good 4.6vgood- but when i moved the tps arm there was no change the voltage just staid at 4.6vas it should-- you're measuring the input voltage (shouldn't change). I took the car for a short (very short drive) and it was stuck in first gear.try re-adjusting the TPS for the correct output based on the new input
Click to expand...
 

I could not adjust the tps after i did the extra ground. It just stayed at i think .75v and would not change if i moved the TPS arm.

so frustrated with this issue. I dont even know where to even look anymore.
 
Rushin said:
yeah i think it did. I will check again tomorrow. But pretty sure it did.
Click to expand...

Find out if it goes to D7 or C5 while you're poking around in there.

Also, does your meter have a face on it to read actual ohms values instead of just relying on a beep to show continuity? Knowing those values is important.
 

Just reread your post. What I meant to say is: when I added an extra ground even tho the input voltage went up to 4.6v the output went up to .75 and did not change with the throttle plate movement.
 
You want to test for continuity between the ground wire coming out of the harness to the eyelet on the dipstick tube stud, the eyelet with the smaller gauge wires. Put one lead there and the other at the TCU plug, with it unplugged, at D7 and then C5 to see which pin is grounding to the eyelet. You should see 0 ohms.
 
OK so i did the Ohm test on the C5 and D7. Two of the wires at the dipstick got wacky reading. Like one got 1 and the other got like 12, 13, 14 and growing and then went to 1. The other one got a reading of -1.88 when i had the positive on the c5 (same for d7). The wire that goes to the dipstick had about half inch of exposed wire. And it looked quite a bit corroded. The eyelet had two wires going to it. Here is a pic of it. It looks rough and corroded. Could this be the issue ?
6fdf5815.jpg


I did put an extra ground on the TPS ground wire on the TPS plug side. The extra ground i routed to the firewall and made sure it was good. That did not do anything and the reading was still 3.89 volts , measuring with the plug connected and testing from the back of the connector.
 
New issue now appeared when it got colder out. When I start the car in the morning an shift into reverse it takes a few seconds for the gear to endage. It does it with somewhat of a jerk. It only happens in reverse and only when it's cold. I have been reading online about this and it looks like it's somewhat common issue on auto transmissions. What usually causes this? Fluid not up to temp?

I have not done anything to the tranny yet. I am going to replace the fluid and filter sometime soon. Btw, what is the proper fluid is it the ATF+4 or Dextron. This is again for a 1990 with aw4.
 
It left the factory with DEX II/III in it.

Effective 2007 Chryco determined that ATF+4 can be used in the AW4:

A/T - ATF + 4 Fluid Usage

NUMBER: 21-014-07

GROUP: Transmission

DATE: October 16, 2007

Do a search, lots of threads discussing this issue.
 
Well pretty sure the issue is almost fixed. Me and mn-jeep member spent a few hours today going through a bunch of stuff trying to figure out what was causing my stutter.

We determined that, first of all, my damn voltmeter that i was using for the past 4 years has bad leads so it was reading about a volt and a half low. How freaking stupid is that. So my TPS harness and TCU are totally fine. But the TPS on the car was bad and was way out of adjustment. So good thing i bought a new TPS just incase.

So we popped a new tps in and got it to adjust perfectly. Took the truck for a spin and it started to shift and idle way better. But the stutter was still there. For a minute Jason thought it could be a mechanical issue with my rear end or tranny.

We get back into the garage, he checks the rear end, it its fine no play in drive shaft, no chipped teeth in the diff.

Thats when we decided to order pizza and have a beer :).

Jason said we should check my plugs and wires. As soon as he got the plugs out he said that the plugs i got are not the best (Platinum Bosh). And the wires were way loose on the cap and the plugs.

Plus while the plugs were out we did a compression test and got 125 on all cylinders except the front one, that one was 115. 125 seems pretty low but at least its pretty consistent.

Ate Pizza.

Parts arrived and we got new plugs in and new wires in. Took the Jeep for a spin. What a difference, the stutter was almost gone. I could only notice a very little misfire when driving home for an hour and a half at about 70mph for about a millimeter on the gas pedal.

So my thought is that this all was caused by bad wires and plugs. Wires were shitty NAPA wires that did not fit snug enough around the plugs and distributor cap.

The remaining stutter is a miss that i am pretty sure is caused by a faulty distributor.

One little detail i forgot to mention before i even posted this thread is that previous owner had a valve cover explode on him while doing a 500 mile drive. He only noticed it when he smelled raw oil inside the car. So when i got the car and replaced the distributor cap it was full of oil. My thought is that oil might have damaged the distributor.

So i am going to get a used distributor and see if this cures the rest of the miss i got.

oh, and thanks for the heads up on the tranny fluid.
 
Look up Renix sensor diagnostics and there is a test for the "sync generator" or "stator " in the distributor. A used dizzy may give you the same symptom if the stator OR IT'S HARNESS is compromised at all.$80 at Napa for a rebuilt dizzy....... That's what my newest project is getting.
 
BTW, congratulations on your successes. I know it was a tough road for you but you stuck with it.

Good lessons here.

Never a$$ume that your tune up hardware is good, especially if you didn't install it and use the proper parts.

Always have 2 voltmeters. They're cheap and worth having extras.
 
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