I ran a scanner on my Sy tonight and found with the KOEO TPS voltage was .61 volts, with the pedal fully depressed it was only 3.4 volts, and showed that the throttle was only 90% open. Truck shows no trouble codes, and is bone stock. Will adjusting the tps sensor provide me with a 100% throttle open figure, or am I looking at a misadjusted throttle cable, etc...? Any help on how to fix would be appreciated.
TPS sensor voltage problem
- Thread starter 10sec5oh
- Start date
SY756
New member
This is a common problem with our trucks. Your main concern is getting the throttle body butterflies 100% open and the computer seeing 100%. The voltages really don't matter that much. The usual problem is that the gas pedal hits the mat/floor before the throttle gets to 100%. There are 2 remedies to this.
1. take out the gas pedal bar and bend it. You might can get it to bend in the truck, but it is not easy.
2. this is the method that I chose. I had some slack in the cable itself, so at the top of the gas bracket, in the cab, where the cable comes threw, I just took the slack out of it (make sure that the throttle itself doesn't open) and then just shim it. This allowed me to get both the throttle and the computer to see 100% open. This option may not work for you if your cable is already tight.
Hope this helps.
1. take out the gas pedal bar and bend it. You might can get it to bend in the truck, but it is not easy.
2. this is the method that I chose. I had some slack in the cable itself, so at the top of the gas bracket, in the cab, where the cable comes threw, I just took the slack out of it (make sure that the throttle itself doesn't open) and then just shim it. This allowed me to get both the throttle and the computer to see 100% open. This option may not work for you if your cable is already tight.
Hope this helps.
jwaller
Evil Genius/SyTy Guru
ok the TPS sensor logic resets itself when you turn the key on and off. so resetting it while the ECM's on may only fix it for a while but you could try it. sounds like you either have a mechanical problem with either your pedel not going all the way down from say the floormat or you might have a streached cable. either way you should physically verify that the WOT pedal means you have a WOT throttle blade. if you are getting True WOT, but the ECM's just not seeing it, then replace the sensor with one from autozone BC it's adjustable and this should solve your problem. either way make sure your getting 100% when your done. its very important. 
not to be a complete ass or anything, but I had this problem and found out that the volts were the important thing. SY/TY manual even says that the percentage is applied to the TPS by the scan tool(if I remember correctly). My problem was never seeing 14.3psi boost target despite having %100 TPS, though my volts were like 3.7 at WOT. There's even a note in the drivability section that says voltage is the measured signal, not percentage. My max boost target was mid to high 12psi, but after shimming the pedal pivot point and replacing my stretched throttle cable I'm now seeing 100% TPS and around 4.3volts at WOT. I do agree, though that the important thing is having the blades open all the way at WOT. I've got plenty of DM runs to illustrate if anyone wants them.
Jeremy
Jeremy
jwaller
Evil Genius/SyTy Guru
thats not right. the only thing the ECM coding works off of is the TPS% which is interpted by the TPS volts. (not turn in the older ECM's) the scaling is reset to whatever your base TPS volts are everytime you turn the key off and on. so as long as you get 100% your fine. no matter what the volts are. just be sure that after you adjust things turn the key off and back on to be sure that it works after the scaling is reset.