TruckGuy
Member
- 141
- 24
- 18
- Location
- Belmont, NC
Has anyone purchased/used the GEP18002829 Throttle Position Sensor? If so, did it work ok? Did you try to set the voltages?
Recently purchased a TPS from KASCAR. The part I received is part# GEP18002829. Not the 12554488 that is currently on my truck. Ok, so maybe just a new part # from GEP. Visually the only difference I noticed was the rotating ‘slot’ where the throttle shaft fits into the TPS is plastic not metal.
I wanted to do a bench test on the new TPS before installing. The ohm readings are dramatically different from the one currently on the truck (M1043A2 6.5 NA GEP). Plus, the ohm readings do not change the I rotate the ‘wiper’ back and forth (they do with the old TPS). At this point I was convinced the new TPS is defective. You should be able to bench test this thing like any other 3 terminal potentiometer, right? I talked to the guys at Kascar and tell them about the ohm readings and that they don’t change when I rotate the “wiper’ and that unit may be bad. They agreed to send me another unit to test. I get the new part…… SAME READINGS !
I seems like this TPS is non-adjustable.
Let me explain….. (sorry, long explanation here, but the details may help someone later)
We know the 2 common ways to adjust the TPS
1. By the TM instructions. Check voltage across leads A and C. If between 4.9v and 5.2v, multiply the voltage by .33 and that’s your target voltage +/- .1v (eg 5.00v x .55 = 1.65v +/- .1v). Install the .646” thick gauge block under the throttle lever. Rotate the throttle until it stops on the gauge block. Check voltage across leads B and C. Adjust to match your target voltage. Remove block. Push throttle to wide open throttle. Voltage across leads B and C should be between 4.5 to 4.6 volts. So this basically sets a voltage based on 33% throttle position.
2. The basic test way…. With throttle at idle position. Check voltage across B and C. Set to .5v. Check voltage at wide open throttle, should be 4.9v or a little less.
OK. So I did the TM method on my truck (with the 12554488 part# TPS). My voltages worked out to be pretty much dead on the example from the TM above. The ‘target’ voltage around 1.65v. I set the TPS and moved on.
My truck seems like it shifts at higher RPMs than it should. So I’ve doing some troubleshooting. That’s the reason for the new TPS. (Also working on adding a tachometer)
So. Back to why I think that the GEP18002829 is a non-adjustable TPS ….
When I bench test, I get the following ohm readings….
Leads A-B = 219 ohms.
Leads B-C = 106 ohms
Leads A_C = 212 ohms.
A is +5v ref
B is V out
C is ground
A TPS is just an adjustable resistor or a potentiometer. Also call a voltage divider. Could be a strange coincidence or just me grasping for straws here. But, using a voltage divider ‘calculator’. Assuming a 5v source. Using A-B (219 ohms) as R1 and B-C (106 ohms) as R2. You get an output voltage of 1.63v. That’s pretty darn close to the 1.65v as seen with the regular set-up.
So. Is the GEP18002829 a non-adjustable TPS set to around 33% throttle??
Recently purchased a TPS from KASCAR. The part I received is part# GEP18002829. Not the 12554488 that is currently on my truck. Ok, so maybe just a new part # from GEP. Visually the only difference I noticed was the rotating ‘slot’ where the throttle shaft fits into the TPS is plastic not metal.
I wanted to do a bench test on the new TPS before installing. The ohm readings are dramatically different from the one currently on the truck (M1043A2 6.5 NA GEP). Plus, the ohm readings do not change the I rotate the ‘wiper’ back and forth (they do with the old TPS). At this point I was convinced the new TPS is defective. You should be able to bench test this thing like any other 3 terminal potentiometer, right? I talked to the guys at Kascar and tell them about the ohm readings and that they don’t change when I rotate the “wiper’ and that unit may be bad. They agreed to send me another unit to test. I get the new part…… SAME READINGS !
I seems like this TPS is non-adjustable.
Let me explain….. (sorry, long explanation here, but the details may help someone later)
We know the 2 common ways to adjust the TPS
1. By the TM instructions. Check voltage across leads A and C. If between 4.9v and 5.2v, multiply the voltage by .33 and that’s your target voltage +/- .1v (eg 5.00v x .55 = 1.65v +/- .1v). Install the .646” thick gauge block under the throttle lever. Rotate the throttle until it stops on the gauge block. Check voltage across leads B and C. Adjust to match your target voltage. Remove block. Push throttle to wide open throttle. Voltage across leads B and C should be between 4.5 to 4.6 volts. So this basically sets a voltage based on 33% throttle position.
2. The basic test way…. With throttle at idle position. Check voltage across B and C. Set to .5v. Check voltage at wide open throttle, should be 4.9v or a little less.
OK. So I did the TM method on my truck (with the 12554488 part# TPS). My voltages worked out to be pretty much dead on the example from the TM above. The ‘target’ voltage around 1.65v. I set the TPS and moved on.
My truck seems like it shifts at higher RPMs than it should. So I’ve doing some troubleshooting. That’s the reason for the new TPS. (Also working on adding a tachometer)
So. Back to why I think that the GEP18002829 is a non-adjustable TPS ….
When I bench test, I get the following ohm readings….
Leads A-B = 219 ohms.
Leads B-C = 106 ohms
Leads A_C = 212 ohms.
A is +5v ref
B is V out
C is ground
A TPS is just an adjustable resistor or a potentiometer. Also call a voltage divider. Could be a strange coincidence or just me grasping for straws here. But, using a voltage divider ‘calculator’. Assuming a 5v source. Using A-B (219 ohms) as R1 and B-C (106 ohms) as R2. You get an output voltage of 1.63v. That’s pretty darn close to the 1.65v as seen with the regular set-up.
So. Is the GEP18002829 a non-adjustable TPS set to around 33% throttle??
