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Discussion Starter · #241 ·
To be clear, you'r measuring the side of Throttle body connector with the wires going into it and not on the throttle body?
Yes, I am measuring the connector or "plug" with the other probe pushed into the detached negative battery terminal. And, as you may remember, when I measured the voltage some time back, there was 0 voltage going to 1 and 4.
 

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Pins 1 and 4 are supposed to be grounded so they should have been zero volts, however, the resistance test shows they are actually not grounded, so both are open between the connector and the PCM or the pins in the PCM connector are not making good contact.
Pin 1 goes to PCB Blue connector E-21 Pin 41
Pin 4 goes to PCB Blue connector E-21 Pin 61

E-21 Pin 41 is top right on the connector pin side ("face")
E-21 Pin 61 is on the right side just below the securing bolt

See if you can determine where the wires are broken.
Rectangle Font Parallel Slope Pattern
 

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Discussion Starter · #243 ·
Pins 1 and 4 are supposed to be grounded so they should have been zero volts, however, the resistance test shows they are actually not grounded, so both are open between the connector and the PCM or the pins in the PCM connector are not making good contact.
Pin 1 does to PCB Blue connector E-21 Pin 41
Pin 4 does to PCB Blue connector E-21 Pin 61

E-21 Pin 41 is top right right on the connector pin side ("face")
E-21 Pin 61 is on the right side just below the securing bolt

See if you can determine where the wires are broken.
View attachment 123965
Pin 1 of PCB Blue connector E-21 Pin 41 (Green with White dash) - No continuity with TSP Pin 1
Pin 4 of PCB Blue connector E-21 Pin 61 (Green with White line) - No continuity With TSP Pin 4

Both wires must be broken somewhere. I would rather re-wire than try to find them. Okay?
 

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Discussion Starter · #245 ·
You will have to splice in new wires to repair the problem.
No problemo. I'll do it manana. One thing I notice by removing the TPS from the newer throttle body was that the "rheostat"-like arm was not in a position to move the motor speed. I opened the "butterfly" before re-attaching the "rheostat", so that it pushes against the motor speed lever. Does this sound right to you?
 

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The TPS sends two DC signals to the PCM that represents actual position of the throttle valve. The mechanical lever on the TPS assembly is operated by throttle valve linkage inside the throttle valve body.

The only way to tell if you installed the TPS correctly is to measure the resistance between pins 5 and 6 and see if the resistance changes as you manually open and close the Throttle Valve.
TPS connector Pin 5 to Pin 6 (TPS#1) resistance with Throttle Valve closed about 720 ohms
TPS connector Pin 5 to Pin 6 (TPS#1) resistance with Throttle Valve open about 4000 ohms
 

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Discussion Starter · #247 ·
The TPS sends two DC signals to the PCM that represents actual position of the throttle valve. The mechanical lever on the TPS assembly is operated by throttle valve linkage inside the throttle valve body.

The only way to tell if you installed the TPS correctly is to measure the resistance between pins 5 and 6 and see if the resistance changes as you manually open and close the Throttle Valve.
TPS connector Pin 5 to Pin 6 (TPS#1) resistance with Throttle Valve closed about 720 ohms
TPS connector Pin 5 to Pin 6 (TPS#1) resistance with Throttle Valve open about 4000 ohms
Buster! IT IS RUNNING!!! You are beyond a doubt, a genius. I will remember you for the rest of my life. I wish there was some way I could reward you. If there is, please let me know. You are truly the Isuzu king. It's been a long haul and your patience with my inexperience and mistakes has been outstanding. You have taught me more about the electrical part of the Trooper than I ever thought I'd know. All I did today after the ohm check is splice into the two wires and run them to the TPS connector. It roared into life, without hesitation.
 

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Glad to hear your truck is running again. So how did 2 wires in the TPS wiring harness and 3 wires in the APS wiring harness become come open circuit if you were not driving the truck and it was running before you installed antenna??
 

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I've been following this thread daily. @Snorkel , I've been rooting for you. And @Buster28 , I'm truly astounded by your knowledge. Absolutely amazing.

I'm so glad this saga had a happy ending.
I too have been following this blow by blow!
 
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Discussion Starter · #251 ·
Glad to hear your truck is running again. So how did 2 wires in the TPS wiring harness and 3 wires in the APS wiring harness become come open circuit if you were not driving the truck and it was running before you installed antenna??
The only other explanation I can offer, came from you. Aliens! Honestly, I don't have a clue. All I know is, I ran it through a carwash that snapped off the antenna. I had a power antenna. I installed it by taking the fender well cover off. I grounded it to the same lug as the original. I routed it through the same grommet, and hooked up the cable behind the glove compartment. I removed the console cover and face cover from the radio. When I pulled the cut piece off the power wire built into the radio, I let go of it. That's when it landed on the radio with a loud spark. The radio fuse blew, and as far as I know, so did all the other stuff. How? I have no idea. I really wish I knew. The greatest lesson I learned, aside from your fantastic assistance is to remove the battery negative cable, no matter what I am working on. A very hard and expensive lesson learn. All I can do is chalk it up to tuition in the school of life.
 

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Discussion Starter · #252 ·
I've been following this thread daily. @Snorkel , I've been rooting for you. And @Buster28 , I'm truly astounded by your knowledge. Absolutely amazing.

I'm so glad this saga had a happy ending.
Thanks for the sentiments and support. All of the credit goes to Buster. I have noticed that he has helped many other Isuzu owners with his expertise. He is truly a professional.
 

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Discussion Starter · #253 ·
I too have been following this blow by blow!
Thank you as well for your behind-the-scenes sentiments and support. I'm glad you and 8th_Note witnessed Buster's professional expertise. I feel like I've been on a trip through a maze, guided by a wizard.
 

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Discussion Starter · #254 ·
Thank you as well for your behind-the-scenes sentiments and support. I'm glad you and 8th_Note witnessed Buster's professional expertise. I feel like I've been on a trip through a maze, guided by a wizard.
Buster, I'm sorry to say I must seek you help again. Everything was fine until yesterday. I went out the start the Trooper and it would not start. I used notes from you and checked the APS connector and found that there is no 5v reference to APS#2, pin 8. Can you help, again? The only thing I did different was turn on the radio and the antenna raised, then turned it off and the antenna lowered. I shut the Trooper off and later, it would not start.
 

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APS2 +5 Vdc reference
PCM E-21 (Blue) Pin 2 connects to APS connector Pin 8 (Green)
Run a continuity check and splice in a new wire if open circuit
 

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Discussion Starter · #256 ·
APS2 +5 Vdc reference
PCM E-21 (Blue) Pin 2 connects to APS connector Pin 8 (Green)
Run a continuity check and splice in a new wire if open circuit
Many thanks, as always. By the way, Pin 2 on E-21 is green. It looks blue until a light is shined on it. It's just darker than the other green wires. The Trooper is running again. Hopefully, "until the wheels fall off".
 
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