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Discussion Starter · #201 ·
The voltages in the annotated Throttle Body connector, CKP connector and APS connector images in your last post are correct.
There may be other issues preventing engine start but at least the throttle control system and CKP voltages are now verified.
Your suspicions were correct. Sadly, it did not start. And the "Reduced Power" light is still on. I tried squirting a little starting fluid into the intake hose, but I think all I got was dieseling for a few seconds.
 

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Discussion Starter · #202 ·
Your suspicions were correct. Sadly, it did not start. And the "Reduced Power" light is still on. I tried squirting a little starting fluid into the intake hose, but I think all I got was dieseling for a few seconds.
If you suspect it is a faulty PCM, Please let me know today. this is the last day of the warrantee.
 

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The PCM is probably OK
If engine tried to start on starting fluid there is spark generated by the coils.
Measure the fuel pressure at the test port located on the LH fuel rail. Turn the Ignition to Run fro 15 seconds and back to Off, the expected pressure is about 40 psi.
 

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Discussion Starter · #204 ·
The PCM is probably OK
If engine tried to start on starting fluid there is spark generated by the coils.
Measure the fuel pressure at the test port located on the LH fuel rail. Turn the Ignition to Run fro 15 seconds and back to Off, the expected pressure is about 40 psi.

First of all, please ignore that Subway order, if it shows up. I hit the wrong key on the spell checker..
Here is a little more info. Even without the starting fluid, the engine tries to start. I had someone try to start it and press and pump the accelerator pedal to see if the throttle moved, it didn't. Does this mean anything? Perhaps this replacement TPS is bad. Also, my fuel pressure gauge does not have the screw on fitting It is not available locally. I would have to order one. So I tested the pressure from the out line at the fuel filter. The results were adequate. Incidentally, the mechanic in town told me he found the fuel pressure to be adequate some time ago.
 

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Discussion Starter · #205 ·
The PCM is probably OK
If engine tried to start on starting fluid there is spark generated by the coils.
Measure the fuel pressure at the test port located on the LH fuel rail. Turn the Ignition to Run fro 15 seconds and back to Off, the expected pressure is about 40 psi.
First of all, please ignore that Subway order, if it shows up. I hit the wrong key on the spell checker..
Here is a little more info. Even without the starting fluid, the engine tries to start. I had someone try to start it and press and pump the accelerator pedal to see if the throttle moved, it didn't. Does this mean anything? Perhaps this replacement TPS is bad. Also, my fuel pressure gauge does not have the screw on fitting It is not available locally. I would have to order one. So I tested the pressure from the out line at the fuel filter. The results were adequate. Incidentally, the mechanic in town told me he found the fuel pressure to be adequate some time ago.There is one other thing but minor. I've noticed that the "up shift" light flashes now. Not that it is very important, but do you happen to know where that sensor is, so I can unplug it?
 

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The Throttle Valve should open and close as the accelerator pedal is operated with the ignition switch in the Run position. The engine does not need to be running. If the Throttle Valve won't move there may be a problem with the Throttle Valve positioning motor. Remove the Throttle body connector and measure the resistance across pins 2 and 3 on the valve body.
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Discussion Starter · #207 ·
The Throttle Valve should open and close as the accelerator pedal is operated with the ignition switch in the Run position. The engine does not need to be running. If the Throttle Valve won't move there may be a problem with the Throttle Valve positioning motor. Remove the Throttle body connector and measure the resistance across pins 2 and 3 on the valve body. View attachment 123851
I got no resistance or beep between 2 & 3. However, when I ground the original TPS to the negative battery terminal I get resistance between 2 & 3. Also, I was wondering. If someone is cranking the Trooper, shouldn't it run if you open the throttle by hand? It doesn't. However, neither does the throttle open when the gas pedal in depressed. Maybe I should re-install the original TPS?.
 

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Pins 2 and 3 on the Throttle Body go to the DC motor that makes the Throttle Valve ("butterfly") open and close using signals from the PCM. The Throttle Position Sensor (TPS) tells the PCM what the position of the Throttle Valve is. I don't understand what you mean by grounding the original TPS to battery negative or how that produces a resistance reading on pins 2 and 3 because pins 2 and 3 are not present in the TPS assembly. What pins did you ground on this connector?
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Discussion Starter · #209 ·
Pins 2 and 3 on the Throttle Body go to the DC motor that makes the Throttle Valve ("butterfly") open and close using signals from the PCM. The Throttle Position Sensor (TPS) tells the PCM what the position of the Throttle Valve is. I don't understand what you mean by grounding the original TPS to battery negative or how that produces a resistance reading on pins 2 and 3 because pins 2 and 3 are not present in the TPS assembly. What pins did you ground on this connector? View attachment 123878
There was no resistance between #2 & #3. However, I grounded the original TSP to the negative battery cable and got resistance between #2 & #3. Must be that the TSP from the Rodeo with 68,000 miles on it I got from eBay back in November is defective. Should I re-install the original TSP?
 

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Discussion Starter · #210 ·
There was no resistance between #2 & #3. However, I grounded the original TSP to the negative battery cable and got resistance between #2 & #3. Must be that the TSP from the Rodeo with 68,000 miles on it I got from eBay back in November is defective. Should I re-install the original TSP?
Perhaps I misunderstood your instructions. By the way, that should read TPS. I may also have measured the wrong two pins. I was going by the configuration for the connector to locate pins 2 & 3. Perhaps you were referring to the bottom pins. Anyhow, I got no resistance between either the top 2&3 or bottom 2&3. Since the TPS is bolted to the engine, I took the original one and grounded it to the negative battery cable to mimic being bolted on. I got resistance on the top two 2&3 and no resistance on the bottom 2&3.
 

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If you look at your spare TPS module you will notice there are only six pins, three for TPS#1 and three for TPS#2. you will also see a opening where pins 2 and 3 exit when the TPS is attached to the Throttle Body. Pins 2 and 3 are attached to the motor inside Throttle Body, measure the resistance across 2 and 3 again and make sure you have your meter set to read resistance.
DO NOT ground anything and DO NOT turn the Ignition On.
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Discussion Starter · #212 ·
Perhaps I misunderstood your instructions. By the way, that should read TPS. I may also have measured the wrong two pins. I was going by the configuration for the connector to locate pins 2 & 3. Perhaps you were referring to the bottom pins. Anyhow, I got no resistance between either the top 2&3 or bottom 2&3. Since the TPS is bolted to the engine, I took the original one and grounded it to the negative battery cable to mimic being bolted on. I got resistance on the top two 2&3 and no resistance on the bottom 2&3.
Perhaps I misunderstood your instructions. By the way, that should read TPS. I may also have measured the wrong two pins. I was going by the configuration for the connector to locate pins 2 & 3. Perhaps you were referring to the bottom pins. Anyhow, I got no resistance between either the top 2&3 or bottom 2&3. Since the TPS is bolted to the engine, I took the original one and grounded it to the negative battery cable to mimic being bolted on. I got resistance on the top two 2&3 and no resistance on the bottom 2&3.
There was no resistance between #2 & #3. However, I grounded the original TSP to the negative battery cable and got resistance between #2 & #3. Must be that the TSP from the Rodeo with 68,000 miles on it I got from eBay back in November is defective. Should I re-install the original TSP?
If you look at your spare TPS module you will notice there are only six pins, three for TPS#1 and three for TPS#2. you will also see a opening where pins 2 and 3 exit when the TPS is attached to the Throttle Body. Pins 2 and 3 are attached to the motor inside Throttle Body, measure the resistance across 2 and 3 again and make sure you have your meter set to read resistance.
DO NOT ground anything and DO NOT turn the Ignition On.
View attachment 123882
If you look at your spare TPS module you will notice there are only six pins, three for TPS#1 and three for TPS#2. you will also see a opening where pins 2 and 3 exit when the TPS is attached to the Throttle Body. Pins 2 and 3 are attached to the motor inside Throttle Body, measure the resistance across 2 and 3 again and make sure you have your meter set to read resistance.
DO NOT ground anything and DO NOT turn the Ignition On.
View attachment 123882
If you look at your spare TPS module you will notice there are only six pins, three for TPS#1 and three for TPS#2. you will also see a opening where pins 2 and 3 exit when the TPS is attached to the Throttle Body. Pins 2 and 3 are attached to the motor inside Throttle Body, measure the resistance across 2 and 3 again and make sure you have your meter set to read resistance.
DO NOT ground anything and DO NOT turn the Ignition On.
View attachment 123882
Okay, I won't mess with the other TPS anymore. For now, when you say #'s 2&3, are you referring to the two pins that attach to the motor? On those I get no resistance. FYI, my original TPS is attached to the complete motor and valve assembly. maybe that was the confusion.
 

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The confusion is the Throttle Position Sensor (TPS) is the the not same component as the Throttle Body assembly so I was not aware the Throttle Body assembly was replaced. This eBay one appears to be defective,

If you measure across pins 2 and 3 of the original Throttle Body assembly what resistance do you measure?
 

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Discussion Starter · #214 ·
The confusion is the Throttle Position Sensor (TPS) is the the not same component as the Throttle Body assembly so I was not aware the Throttle Body assembly was replaced. This eBay one appears to be defective,

If you measure across pins 2 and 3 of the original Throttle Body assembly what resistance do you measure?
Well, that was my mistake. I apologize for not knowing the nomenclature. This is why I grounded the original throttle body and TPS. I wanted to test the 2 & 3 pins. I got a resistance on them. I will install the original one tomorrow, so we can really check this out properly. To be clear, you are referring to the motor pins, the two top middle ones that protrude through the opening in the TPS, correct?
 

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What is the resistance across pins 2 and 3?
What is the resistance between pin 2 and the Throttle Body shell ("ground")
What is the resistance between pin 3 and the Throttle Body shell ("ground")


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Discussion Starter · #216 ·
What is the resistance across pins 2 and 3?
What is the resistance between pin 2 and the Throttle Body shell ("ground")
What is the resistance between pin 3 and the Throttle Body shell ("ground")


View attachment 123895
On the TPS throttle body presently installed I got resistance of 1.5; 0; 0. ohms
On the original TPS with the throttle body grounded to the negative battery lead, I got 2.3; 0; 0 ohms.

I guess yesterday I wasn't making good contact with #'s 2 & 3
 

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Well, in view of your new test info it appears the throttle body now on the truck is probably OK
The no start problem seems to be separate from the throttle control problem.

Remove the accelerator pedal assembly from the truck so the accelerator position sensor can be tested, It is bolted to the firewall with two bolts.

You need to measure the fuel pressure at the fuel rail test port to be sure there is correct pressure for start up.
 

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Discussion Starter · #218 ·
Well, in view of your new test info it appears the throttle body now on the truck is probably OK
The no start problem seems to be separate from the throttle control problem.

Remove the accelerator pedal assembly from the truck so the accelerator position sensor can be tested, It is bolted to the firewall with two bolts.

You need to measure the fuel pressure at the fuel rail test port to be sure there is correct pressure for start up.
I have to get a fuel pressure tester. How do I test the APS? This part is brand new, but it still could be faulty.
 

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Disconnect the APS electrical connector and remove the accelerator pedal assembly from the truck. Do Not remove the APS from the pedal assembly. It needs to be tested as it is mounted and adjusted on the pedal assembly. I will tell you how to test the APS when you'r ready to test.
 

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Discussion Starter · #220 ·
Disconnect the APS electrical connector and remove the accelerator pedal assembly from the truck. Do Not remove the APS from the pedal assembly. It needs to be tested as it is mounted and adjusted on the pedal assembly. I will tell you how to test the APS when you'r ready to test.
I'll have the fuel pressure test by Friday. I am ready to test the APS.
 
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