sansocal

I am having shifting issues when the jeep is warm and the resistance for the TPS ground to negative battery post is about 1.9. I have a new negative battery cord and soldered together the 6 ground wires in the harness by the firewall. I also cleaned all the grounds from the firewall to block, and the connections by the oil dipstick tube.

Is there anything else I can do to make this circuit better?

DFlintstone

Wheres Cruiser? We need one of those spotlight deals like they shine up to call Batman! Can you isolate it? Block to neg post. Body to ground wires ect...

Plenty have added a ground from the dipstick tube bolt to a stud below the shock mount. I added one from a small bolt on the AC compressor to the a radiator mount bolt.

I'm no wiz on this stuff but I noticed that the "NSS" does allot more than stop starting in gear. Guess it also gives signals to the TCU. It seems to fail allot as a NSS, no idea if its common to cause shifting issues, but it stands to reason.

cruiser54

Didn't I post that yesterday?

Anyway the ground circuit you tested was on the flat connector, right? That only affects the engine. The square connector is for the trans. Your TPS is really two TPSs in one and has separate potentiometers in each side to give info to two seperate control units.

My recommendation as far as shifting issues is to test the square connector per the instructions. Even before that I would find the trans control connectors over by the trand dipstick tube. They're kinda large and one is black and the other gray. Unplug them, spray out both sides with electronics cleaner, inspect for bent pins and plug them back in. All the info between the trans, NSS and TCU travel through those connectors.

As far as the 1.9 ohms of resistance in the sensor ground circuit, I have a fix for that which requires soldering. Let me know.

sansocal

I am attaching an excel sheet with the resistance values I found today.



Before I go any further I have three questions:
-I am assuming the resistance goes up with the key on because there is all that energy running from all those sensors, would a new (and thicker) ground strap be less affected from the juice, and keep a better ground potential ALL the time?

-Can I just run a cable from block to frame and solve all my issues?

cruiser54

My rule of thumb when checking these is to have teh key on when checking voltage, key off when checking resistance.
Your sensor ground circuit is a little high. Less than 1 ohm is what you want.
To simplify the general grounding issues with these Jeeps I do the following:

Add a #4 cable from the firewall ground point to the rearmost bolt of the fuel injection rail.
Add a #4 cable from the dipstick tube stud over to the passenger side inner fender. There is an 8mm stud almost directly below theupper shock mounting point.
Add a #6 cable from the negative battery terminal to one of the 10mm headed bolts on the radiator support.
Be sure to clean all connections to bare metal in the process.