Bad output voltage from TPS?

[smithmiester]

So after I bring the 6 wires together, there will still be a seven wire headed towards the dipstick ground, right?

 

[cruiser54]

No. There will be two sets of three. One set from the IAT area and one set from the MAP area. Actually, once you open up the harness it will all make sense. You're eliminating the single wire between the two splices, along with the splices, and soldering the 2 groups of thress wires together.

 

[Hellbent]

interesting. i had never seen this explanation before. might have to do this over the weekend, just as a preventative thing.

Here it is and some people have a hard time understanding it while others grasp it just fine. Feel free to ask questions.


Find your Intake Air Temp sensor. It's the sensor just to the rear of the throttle body, has 2 wires, and screws into the intake manifold.
Where it's connector plugs into the harness you will see that one of the wires on the harness side　is brown with a white stripe. Follow the brown with white strip wire back into the harness. You'll have to open up the split-loom plastic sheathing to follow it. It will come to a splice with 2 other brown with white wires. They're from the TPS and the CTS. The 3 wires will be　 spliced to a single wire headed toward the C101 connector if you have an 87 or 88. If you have an 89 or 90, you do not have the C101 bulkhead connector.
　
Now go to the MAP sensor. Follow the brown with white wire into the harness from there. You will find a splice with 2 more brown with white wires. At the splice you will find the 3 wires connected to a single brown with white wire going toward the C101, or just along the firewall towards the engine if you have an 89 or 90. Along with the MAP sensor that you traced, they are the ECU sensor ground port and the diagnostic connector on the passenger inner fender.
　
You now have 2 sets of 3 brown with white wires, one near the firewall and one near the engine.
　
Cut the splices out of each set of wires eliminating not only the crappy factory splices, but also the single wire between them. Bring both sets of 3 wires together. Solder the 2 sets of wires together and insulate them properly with tape or shrink tubing.
　
Zip-tie up your new sensor loom to allow for engine movement.　I prefer to cover it with some new split-loom or wrap it neatly with electrical tape when done.
　
　
Revised 12-02-2011

 

[cruiser54]

interesting. i had never seen this explanation before. might have to do this over the weekend, just as a preventative thing.

Excellent idea. You can test it though like explained above. On my wife's 88 there was 58 to 74 ohms of resistance when wiggling the harness!!! That's what brought about this fix.

 

[smithmiester]

So i did my best to reground the TPS. I piggy-backed the wire next to the connector, and ran it to the firewall, and also soldered another wire to the junction inside the harness, and ran that to the firewall. My harness was not set-up the way cruiser54 described it in the tech write-up. there was not 2 3-wire connections, but one junction with four wires going in, and two coming out. i dont know if someone else had already modified the harness, but the crimps seemed to be in really good condition, and i didnt feel that they needed to be soldered. The problem is that it didnt fix the issue. Im now getting less than one ohm of resistance with the power on, but still getting almost 10 ohms of resistance when the engine is running, and im still getting no output voltage from the TPS. I dont know what to do. Any advice?

 

[cruiser54]

What is the resistance with the power off? How old is your TPS?

 

[smithmiester]

The TPS was brand new about three months ago. When i took the old motor out, i had good output voltage. I had it tuned to EXACTLY .83 of input.

 

[cruiser54]

What is the resistance with the power off?