Please help with my TPS

http://s199.photobucket.com/user/sc...E8-1970-000002043C02374B_zpse1b627dc.mp4.html

A little background 92 Cherokee XJ 106xxx 3k on new motor 6 inch lift stock gearing.

So I was out wheeling last week and my check engine light came on and it started sputtering like in the video. It's OBD1 so I did the key thing and came up with a code 24 bad TPS. I stopped at Autozone on the way home and picked up a new TPS. I installed it but the problem continued so I replaced it thanks to the lifetime warranty but that didn't work either. I ended up getting one from Jeep but that didn't help either. I did the refresh on all the grounds and even ran new grounds to all the locations under the hood.
Below are the voltages I got when checking them.

The original one
Constant 5.02 vdc
idle .657
Wot 3.715

Autozone one
constant 5.019 vdc
idle .629
wot 3.633

Jeep one
Constant 5.02
idle .706
wot 3.743

Can all of them be bad?
Is there something else I should be checking?

I really need to get this thing running before this weekend any help would be appreciated.

Mark

scubamark13 said:

I did the refresh on all the grounds and even ran new grounds to all the locations under the hood.

Click to expand...

Just to be clear, you did not run new grounds to the sensors, right?

Nope just from the battery to the body grounds and to the dipstick tube.

I'd set my meter on a low volt scale and test from the TPS ground wire (black with a stripe) to the battery negative pole and see how much voltage is in the ground wire. I call it standing voltage. The higher the standing voltage the more resistance you have in the ground circuit. A good quick test to see if your grounds are constipated.

Don't forget about the head to firewall ground and the small wires to the dipstick ground.

I had TPS issues once and eventually found where my mechanic had sprayed the TPS connector with WD-40. My point is the connector has to be clean, no oil. I use a top quality electronics contact cleaning spray, pricey, but a little goes a long ways.

Just thinking outloud here, but could you run
a jumper wire from the TPS ground directly to
the battery negative post, to confirm the bad
ground?

If the problem is then fixed, then maybe check
the ECM connector plug for a bad connection?

8Mud said:

......I had TPS issues once and eventually found where my mechanic had sprayed the TPS connector with WD-40......

Click to expand...

Interesting. What about the use of dielectric grease?
The reason I ask, is that I use the stuff on all
electrical connections and might want to rethink...?

Runnin'OnEmpty said:

Interesting. What about the use of dielectric grease?
The reason I ask, is that I use the stuff on all
electrical connections and might want to rethink...?

Click to expand...

I gave up on dielectric grease a long time ago. Reason being, I have my doubts about it being resistance neutral in very low voltage situations. I found out through self testing that WD-40 has significant resistance, especially after it tacks up and evaporates to a film.

The issue IMO is, for example, six volts has a very low leak down through moisture (non evaporated/ dirty water) to ground from most any exposed connection. In other words, dirty water (dirty being defined as water with impurities) has a significant resistance at six volts, less at 9 volts and even less at 12 volts. Water is considered a conductor. Compare water to dielectric paste, dielectric paste is supposed to be a low conductor or even an insulator. My guess is dielectric paste conducts through a micron thick coating but not as it gets thicker. I wonder what it's properties are at 0.2 volts or point 0.8 volts?

I doubt it's properties are the same at decimal point low (sensor) voltages as they are at 12 volts.

I actually use a conductive paste (not a dielectric paste) on many of my Renix sensor connectors, I found a tube of the stuff at a model railroad shop, they use it to connect the tracks together and get good contact.

I've known many guys who did engine swaps (at the auto hobby shop I worked at) and had sensor issues when they were done. Most of the time it was oil on their hands and smeared onto the connectors and/or coolant where it wasn't supposed to be. Oil (or grease) is an insulator, coolant conducts better than plain water. After my experiences with oil and grease I'm hesitant to use dielectric paste on low voltage sensor connectors.

I've never done any kind of significant tests on dielectric grease. I good test might be to take two coins and put a dab of dielectric grease between them and measure the resistance with no pressure and then incrementally increase the pressure (with a clamp) and see if the resistance changes any or significantly. I wonder about the properties of dielectric grease at very low voltages and have unsubstantiated doubts about it's properties at very low voltages. IMO it almost has to leave a micron thick film on the connector mating surfaces, that is likely irrelevant at say 12 volts, where it might be a factor at decimal point voltage.. Just a WAG (wild arsed guess) that may or not be fact.

This would be a good question for 5-90 or EcoMike to answer, they are much more knowledgeable about this type of stuff than I am. I'm just going with my gut here.

8Mud, thanks for sharing your thoughts. What you say
makes a lot of sense. I too have a can of the conductive
paste you mentioned. It seems to be a mixture of
copper dust and grease; I use it mainly on battery
cable connections.