GM TPS Sensor starting at 100% while idle
Thread Starter
Launching!
Joined: Jun 2014
Posts: 204
Likes: 8
From: Houston
GM TPS Sensor starting at 100% while idle So when I have the HP Tuner software hooked up to my OBD2 port and turn the key to on my TPS reading is 100%. As I give it more gas the percentage decreases.
I spoke with my tuner and he advised me to switch the wires in the TPS pigtail as they were backwards. Well I have one ground wire and then a 5V supply and then the signal wire. I went ahead and flipped the wires in the pigtail, but I am still getting the same read on HP tuners saying it is at 100% on the TPS.
I then checked the voltage on the pigtail, and I have 5V on both wires. As I open the throttle the voltage goes down. I thought that the voltage at idle should be close to 0 and as the throttle opens the voltage goes up, but I have the inverse. The voltage goes down as I open the throttle.
Can someone help me on this, I am at a lose here. I appreciate any help. Thanks guys.
I spoke with my tuner and he advised me to switch the wires in the TPS pigtail as they were backwards. Well I have one ground wire and then a 5V supply and then the signal wire. I went ahead and flipped the wires in the pigtail, but I am still getting the same read on HP tuners saying it is at 100% on the TPS.
I then checked the voltage on the pigtail, and I have 5V on both wires. As I open the throttle the voltage goes down. I thought that the voltage at idle should be close to 0 and as the throttle opens the voltage goes up, but I have the inverse. The voltage goes down as I open the throttle.
Can someone help me on this, I am at a lose here. I appreciate any help. Thanks guys.
Thread Starter
Launching!
Joined: Jun 2014
Posts: 204
Likes: 8
From: Houston
I spoke with FAST this morning and they recommended me getting another TPS sensor, and see if that fixed the issue. The recommended part ACDelco 213-895 for this FAST 4150 Part#307603
Thread Starter
Launching!
Joined: Jun 2014
Posts: 204
Likes: 8
From: Houston
Well I figured out the issue with the TPS reading out at 100% at idle. The wiring harness from Speartech was incorrect. The ground wire was in the wrong pin. Once I switched that the TPS went to reading 0% at idle and 100% at WOT.
I was able to look at an OEM TPS pigtail from my old harness, and right away I saw that the ground wire was in the incorrect position. So that little issue is done. I appreciate the help.
I was able to look at an OEM TPS pigtail from my old harness, and right away I saw that the ground wire was in the incorrect position. So that little issue is done. I appreciate the help.
On The Tree
Joined: Sep 2007
Posts: 196
Likes: 0
Sorry about that Mike. It looks like we built the harness for a TB that opened up in the reverse manner since you were using the 4BBL TB. We were misinformed on which way the throttle blade opens up and I apologize for the inconvenience!
Thread Starter
Launching!
Joined: Jun 2014
Posts: 204
Likes: 8
From: Houston
Hey it is a great product!! I am not trying to throw anyone under the bus. There are so many variables when you are building these conversion cars, and you guys have done a great job with a greenie like myself.
One question...I have not been able to take this thing for a test drive since I repinned the TPS. It seemed before the car was stuck in a "limp mode" in 2nd. It also would not shift. In your vast experience should I be getting shifts now and be able to go through all the gears? I am running the 4l80e. Thanks guys!
One question...I have not been able to take this thing for a test drive since I repinned the TPS. It seemed before the car was stuck in a "limp mode" in 2nd. It also would not shift. In your vast experience should I be getting shifts now and be able to go through all the gears? I am running the 4l80e. Thanks guys!
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On The Tree
Joined: Sep 2007
Posts: 196
Likes: 0
I would test drive and see whats going on now with TPS fixed. Not sure what happens when ECM is showing incorrect TPS information. I'm sure it has a dramatic affect on everything. I would also make sure the PCM has been properly programmed for 4L80 application.
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