arpunk

Input voltage is 4.87
4.87 x .83 = 4.04

Maybe you meant to say that your output voltage should be 83% less than your input voltage, AKA 17%? Or perhaps you are referring to the automatic transmission testing procedure on the 4-pin connector? That would be .83 of input (terminals D and A) on terminals B and D.

Regardless, I don’t have an automatic transmission.

cruiser54

Yep. I messed up.
If you turned your TPS down to 12 or 13 and the idle didn't change, I'm thinking the TPS is okay.
Generally, turning it down was done to reduce a high idle flare and sometimes sticking on start-up.

arpunk

So here’s where I’m confused. In your write-up, you say that if after adjusting the TPS the idle is high, turn the TPS down until it idles correctly and then turn it back up. I’ve seen multiple people (myself included) have experiences where turning their TPS Output Voltage down does not drop their idle to correct levels. You just wrote that if turning my idle down doesn’t drop the idle, then the TPS is most likely functioning properly.

So - what function does the TPS serve that would affect idle, and how would turning the output volts down and then back up, assuming this did affect idle speed, not result in the idle dropping and then coming back up in proportion to the output voltage? Why would the idle speed drop down with the TPS output volts being lowered but not come right back up when the output volts are increased back?

cruiser54

Has your idle speed been determined using a tachometer? What does your factory tach read at this point?
Weren't the injector o-rings causing the "high idle" after cleaning the throttle body? Or was the higher idle just from cleaning the throttle body?
I hate to see a good possibly factory TPS replaced for no reason and installing a newer inferior part causing issues in the future.

arpunk

Idle speed has not been determined by a tech yet. I’m waiting to see if someone I know has the capability to test.
High(er) idle started immediately after cleaning TB/IAC. Went from 750ish to 1000 on the gauge cluster tach.
After changing injectors and running the car for five minutes, it was running at 750 but it was 34 degrees out. After warming up the next day it crept back up to 1000. It was driven sufficiently.

Would there be a marking on the factory TPS so that I could confirm it was OEM? If I buy a new one and it doesn’t fix it I will be returning it and putting the original back in. If it does fix it I will be returning it but buying a MOPAR TPS (they aren’t very lenient with returns).

MJ/XJ Owner

I was reading your renix tips. Brings back memories. I see you have the crank sensor cranking voltage in there. That's all great information to share. I worked for a jeep dealer for 14 years. I joined this group because I found some helpful information on here. Hopefully I can help some people in the future.

cruiser54

Does your TPS only have one pigtail?

I just went out to the parts shed and looked at 5 or 6 TPSs. No clear markings, but I'm assuming the OEM ones had a plastic clip on the pigtail that pressed into a little bracket that bolted down somewhere.
I could faintly see what looked like EF89 something or other. Likely a worn off OE part number.

cruiser54

Remember the Eagle Premiers? And their issues with low CPS output voltage?

arpunk

My TPS doesn’t have a pigtail. I’ll take a picture after I walk these dogs.

arpunk

TPS says 3194 9224

MJ/XJ Owner

We had more issues with the 4.0 liter than the 3.0 liter premiers, but we didn't see many premiers. I always liked that they were a free wheeling engine so when the water pump or idler pulley failed you didn't bend valves. I still have the harmonic balancer puller for them, haven't used it since. LOL. Renault made a quirky but easy to work on fuel management system once you figured them out. But I guess anything you work on for a living you figure out the weak links.

The 87-88 Jeep we bypassed the harness on the firewall for both CPS and TPS. I remember we discovered the problem the hard way, when we would do a service on the jeep we always steam cleaned the engines. We quickly discovered the weak links. That's why I was saying we could have our DRB II tester hooked up and blow air into the connections and watch the TPS readings change and the idle come back down. I'm surprised that was never a recall and and only a TSB.

For no starts we checked the cranking voltage for the CPS and set it to .5 volts AC current and that fixed no start problems 99% of the time.

lawsoncl

The single output looks like the picture. It's the dual-output that has the two pigtails out to connectors.
The MOPAR part number for the manual TPS is 3300-3194. The 9224 could be a date stamp, which would imply it's been replaced before.

cruiser54

I wouldn't be in a hurry to replace the TPS just yet.
How about observing the voltage readings while moving the TPS at idle and see if there are any abnormalities? You've kinda done that already?

Original IAC? Throttle body well sealed at manifold? Sprayed it?
Throttle body not closing completely since cleaning? Push it closed lightly with your finger.

cruiser54

Spray around the throttle shaft and base of the throttle body, and the MAP hose and connections.

cruiser54

I'm going to work now.
Consider what I've posted above and I'll come back later.