TPS / TCU Problems

OK. First, I quit smoking and am in the most terrible, grouchy, cranky, and worst general mood I have ever been in. It's making this job almost impossible because I can't concentrate for more than about 10 seconds and I am incredibly impatient.

This may not be the best time to do this but I need to get the Chief back up and running. Having some trouble with the AW4 tranny shifting funny and TC acting up. TPS right? That's kinda it. Get 4.12 VDC to the TPS. Try another ground and I get a perfect 5.05VDC. So I guess my ground is bad. Where does the TPS ground to, the TCU? If someone could help me get this ground figured out I'm pretty sure this is my problem.

Thanks!

Let me clarify this a little... The orange and white wire AKA wire "D" is the ground for the TPS. It doesn't make a great ground connection.... somewhere in the neighborhood of 10 megs... Where does this wire go??? I'd like to clean it up and get to ground better.

Hawaiian Style said:

Let me clarify this a little... The orange and white wire AKA wire "D" is the ground for the TPS. It doesn't make a great ground connection.... somewhere in the neighborhood of 10 megs... Where does this wire go??? I'd like to clean it up and get to ground better.

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10 megs doesn't sound right. that would give you no ground at all. Be sure you are on the right wire. I found the ground wire at the TPS connector, and spliced in a short wire with a ring connector on the end which I fastened under a screw on the engine. Fixed my ground problems perfectly. But if you get the wrong wire, you may do more damage that good. Be careful. Good luck.

Damn, this sucks!

Been messing with this all day. My basic problem is I am only getting 4.2 volts at the TPS. Thats well below the 5 it supposed to have. Guess I'll keep on it...

Hawaiian Style said:

Damn, this sucks!

Been messing with this all day. My basic problem is I am only getting 4.2 volts at the TPS. Thats well below the 5 it supposed to have. Guess I'll keep on it...

Click to expand...

I doubt you'll ever get the full 5. 4.2 is not great (something like 4.6 is more typical), but it should be enough to run. If you can ensure you have the correct ground wire, I believe you can ground it to any convenient point. The Renix ECU works on the "hot" side of the circuit, and all the sensors share the common ground. Just make sure you have the right wire, so you don't fry something. I'm away from home, without any diagrams, so I can't help with wire identification.

Hey, What he said. Run a jumper ground direct to the firewall from the TPS ground connection. Adding a jumper wire from the battery ground on the front of the block around to the 'normal' ground point on the firewall is also a good idea. (Ground strap on the back of the motor is a source of trouble + grounding through the block is a poor design idea to begin with.)

Here's a link from my Download Page for a zip file w/ the TPS adjustments or ya can look on my Tech page under Basic Sensors Diagnostics for the short form how to.

HTH

lunghd said:

Hey, What he said. Run a jumper ground direct to the firewall from the TPS ground connection. Adding a jumper wire from the battery ground on the front of the block around to the 'normal' ground point on the firewall is also a good idea. (Ground strap on the back of the motor is a source of trouble + grounding through the block is a poor design idea to begin with.)

Here's a link from my Download Page for a zip file w/ the TPS adjustments or ya can look on my Tech page under Basic Sensors Diagnostics for the short form how to.

HTH

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Just a quick note - The file is good for your Chief but for others: My info is for RENIX (non-HO) engines...

Thanks guys.... I really appreciate your help. :sunshine:

The 5.0 is from the FSM and the really strange part is that if I run a new ground to TPS I get 5.05 volts. I was hoping someone would know where the TCU groundsso I could check it instead of just creating a new one. I guess I'll just go ahead and do that anyway. Hopefully this will solve my shifting problems and the torque converter issue. This problem is really driving me crazy:flamemad: - I can drive it but it makes me crazy when it shifts funky.

What a horrible week to quit smoking :hang:

The 5.0 volts specified from the fsm is approximate. Mine is about 5.25. A good ground and a proper ratio on the adjustment is the important thing. My fsm says the wire at the B position on the three wire tps connector is the ground wire. On your square tps connector for your auto tranny computer hook up the ground wire is at position D on the connector (a Tn/or wire I believe. All the above for pre 91 renix xjs w. 4.0 and auto tranny. Good Luck. Greg

OK, got the electronic part solved... I think. Found the accelerator cable has a broken mount now... JB Welding to see if I can save 20 bucks at NAPA.

Could be part of the problem with the idle and tranny troubles. We'll see in 10 more hours.