TPS Screwed Up Again
Thread Starter
Joined: Aug 2004
Posts: 11,258
Likes: 146
From: Pace, FL
TPS Screwed Up Again Had a problem last year... turned out to be the ABS module shorting out the 5V lead causing it to be over 6V.
Well a new problem has emerged. Tried 3 different TPS sensors (two new ones both read much higher than the OE - including the ACDelco one, so I don't know what's up).
But I've tried both a NW 102 and a FAST 102 TB. FAST closes down tighter so I can get voltage to .45V with the OE TPS. NW is around .55V all the way closed down.
Issue is I see 1% TPS all the time even with a TPS relearn. And at those voltages.
So I decided to test... 5V lead sees 5.05V when grounded to battery. The ground lead sees about 11.88V when grounded to the battery. Both within spec. The PCM lead however shows 6.6V when grounded to the battery? Isn't that supposed to show between .4 and 4.9 or so? Granted, I didn't have it hooked up to the TPS when I did the test, what's the free air value supposed to be? If that all checks out and it's doing it with all my sensors, do I just need to rewrite all when I flash the PCM?
I cleared all codes. Did TPS relearn multiple times...
Other symptoms were I'd drive for 30 mins. Everything was fine. And suddenly when I came to a stop I'd be reading .72 or .81V or something and 4% throttle. When just a few mins before I was at .57V and 0% throttle. I checked the NW TB and it looked like the shaft may have moved on me. So I was going to try my FAST TB but can't get a reset to 0%.
Hep.
Well a new problem has emerged. Tried 3 different TPS sensors (two new ones both read much higher than the OE - including the ACDelco one, so I don't know what's up).
But I've tried both a NW 102 and a FAST 102 TB. FAST closes down tighter so I can get voltage to .45V with the OE TPS. NW is around .55V all the way closed down.
Issue is I see 1% TPS all the time even with a TPS relearn. And at those voltages.
So I decided to test... 5V lead sees 5.05V when grounded to battery. The ground lead sees about 11.88V when grounded to the battery. Both within spec. The PCM lead however shows 6.6V when grounded to the battery? Isn't that supposed to show between .4 and 4.9 or so? Granted, I didn't have it hooked up to the TPS when I did the test, what's the free air value supposed to be? If that all checks out and it's doing it with all my sensors, do I just need to rewrite all when I flash the PCM?
I cleared all codes. Did TPS relearn multiple times...
Other symptoms were I'd drive for 30 mins. Everything was fine. And suddenly when I came to a stop I'd be reading .72 or .81V or something and 4% throttle. When just a few mins before I was at .57V and 0% throttle. I checked the NW TB and it looked like the shaft may have moved on me. So I was going to try my FAST TB but can't get a reset to 0%.
Hep.
Thread Starter
Joined: Aug 2004
Posts: 11,258
Likes: 146
From: Pace, FL
One other thing, when I scan in HPT, I can watch the TPS voltage. And it's smooth. With the NW it was .55V closed and 4.39V open.
It was driving fine until yesterday. But it had been having the 4% TPS after a 30 min drive regularly. I would just TPS reset and it'd be fine to drive. Even when hot that same day.
Should I go with the ACDelco sensor that reads higher? Let me try that. TPS sensor might just be fucked. But the TPS signal reading 6V is also crap.
It was driving fine until yesterday. But it had been having the 4% TPS after a 30 min drive regularly. I would just TPS reset and it'd be fine to drive. Even when hot that same day.
Should I go with the ACDelco sensor that reads higher? Let me try that. TPS sensor might just be fucked. But the TPS signal reading 6V is also crap.
Last edited by JakeFusion; Oct 19, 2016 at 09:47 AM.
Thread Starter
Joined: Aug 2004
Posts: 11,258
Likes: 146
From: Pace, FL
Does anyone know what the voltage readout should be on the PCM Signal when unplugged with Key On Engine Off? I'm seeing 6.6V... everything else is okay and the voltage tracks through HPT perfectly. I just can't get it to read 0% with any TPS.
Meet CoreyD - he may be going through a similar type of thing: https://ls1tech.com/forums/general-m...connector.html
Are you measuring the supply voltage and ground with the connector off? You'll get odd voltages otherwise. The only thing that I'd expect you could reliably probe with the connector hooked up would be the signal wire.
You have an aftermarket throttle body, right? Have you tried taking the sensor off and seeing what your scanner shows when you turn it by hand?
You have an aftermarket throttle body, right? Have you tried taking the sensor off and seeing what your scanner shows when you turn it by hand?
Trending Topics
Thread Starter
Joined: Aug 2004
Posts: 11,258
Likes: 146
From: Pace, FL
Yeah. Aftermarket TB. Switched back to the FAST. I have both a FAST and NW. Both have their pros and cons. lol
New ACDelco sensor and FAST it seems to be okay. For now. Reading .55V. And the blade is cracked open a bit. The NW was loose and the blade stop was changing on me. So I was also chasing that. The FAST is much stiffer.
The issue is the FAST IAC passage is too small.
New ACDelco sensor and FAST it seems to be okay. For now. Reading .55V. And the blade is cracked open a bit. The NW was loose and the blade stop was changing on me. So I was also chasing that. The FAST is much stiffer.
The issue is the FAST IAC passage is too small.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Did you ever figure this out? I'm having a code P0122 and all the voltages seem to check out
Grey 5.03 volts
Blue 0.6 volts (closed) 4.5 volts (WOT)
Black 0.033 volts
One weird thing and I don't know if this is normal, opening the throttle until it hits 2 volts, at 2 volts the multimeter will read "OL" for a split second and go back to normal. I posted a video of opening the throttle.
My thread
https://ls1tech.com/forums/general-m...ing-p0122.html
Grey 5.03 volts
Blue 0.6 volts (closed) 4.5 volts (WOT)
Black 0.033 volts
One weird thing and I don't know if this is normal, opening the throttle until it hits 2 volts, at 2 volts the multimeter will read "OL" for a split second and go back to normal. I posted a video of opening the throttle.
My thread
https://ls1tech.com/forums/general-m...ing-p0122.html