96 F150 5.8 High Idle... and I've replaced everything! Please help!
11-27-2011
#21
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Join Date: Jan 2011
Location: Durham, NC
Posts: 646
I double checked the TPS sensor and voltage (1.01 VDC) before I bolted the throttle body back on. The throttle cables didn't move the throttle arm. I opened and closed the throttle and watched the voltage change.
It always went back to 1.01 VDC.
Is the IAC "variable" or is it "two position"?
Thanks again for all the help....
It always went back to 1.01 VDC.
Is the IAC "variable" or is it "two position"?
Thanks again for all the help....
When you set the TPS voltage, did you rotate the sensor, or adjust the throttle plate stop screw?
When you measured the 1.01V, were you using the GND terminal on the TPS sensor? Do you measure 5V (or close to it) on the 3rd TPS terminal?
11-27-2011
#22
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Thread Starter
Join Date: Nov 2011
Posts: 26
The IAC is "variable", or analog, not digital (open or closed)
When you set the TPS voltage, did you rotate the sensor, or adjust the throttle plate stop screw?
When you measured the 1.01V, were you using the GND terminal on the TPS sensor? Do you measure 5V (or close to it) on the 3rd TPS terminal?
When you set the TPS voltage, did you rotate the sensor, or adjust the throttle plate stop screw?
When you measured the 1.01V, were you using the GND terminal on the TPS sensor? Do you measure 5V (or close to it) on the 3rd TPS terminal?
I rotated the TPS to get the 1v, then I tightened the screws (I also added purple Loctite on the screws).
Everything I have read says NOT to adjust the stop screw.
I followed the instructions in the Haynes manual. It showed the two wires to measure across to find the voltage. I did not look at the other wire as it was not mentioned in the Haynes manual.
11-27-2011
#25
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Join Date: Jan 2011
Location: Durham, NC
Posts: 646
The 15 inches of Hg is on the low side. Is the vacuum gauge steady at this reading, or is it fluctuating? One other source of a vacuum leak is the vacuum line going to the brake booster. Have you tried pulling this line from the brake booster, and plugging it?
11-27-2011
#27
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Join Date: Jan 2011
Location: Durham, NC
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11-30-2011
#29
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Join Date: Nov 2011
Posts: 8
TPS:
I rotated the TPS to get the 1v, then I tightened the screws (I also added purple Loctite on the screws).
Everything I have read says NOT to adjust the stop screw.
I followed the instructions in the Haynes manual. It showed the two wires to measure across to find the voltage. I did not look at the other wire as it was not mentioned in the Haynes manual.
I rotated the TPS to get the 1v, then I tightened the screws (I also added purple Loctite on the screws).
Everything I have read says NOT to adjust the stop screw.
I followed the instructions in the Haynes manual. It showed the two wires to measure across to find the voltage. I did not look at the other wire as it was not mentioned in the Haynes manual.
what i do when setting it is i put the TPS at mid travel then adjust the idle screw to get .8 at the TPS.try it and report back with your findings Deet.
Last edited by Dave; 11-30-2011 at 01:57 PM.
11-30-2011
#30
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Thread Starter
Join Date: Nov 2011
Posts: 26
Update...
I just borrowed a scan tool from my neighbor. I hooked it up with the engine OFF and it said that the TPS was at 20%.
This has GOT to be the problem.
I am going out to start wrenching and I'll let you know if setting the TPS down to 0.6 or 0.8 VDC works. The scan tool will verify that the TPS is reading lower...
I just borrowed a scan tool from my neighbor. I hooked it up with the engine OFF and it said that the TPS was at 20%.
This has GOT to be the problem.
I am going out to start wrenching and I'll let you know if setting the TPS down to 0.6 or 0.8 VDC works. The scan tool will verify that the TPS is reading lower...