Throttle Position Sensor, "Huh"? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mountie · 06-20-2017, 08:45 PM

1988 C2500 5.7 TBI -GMC.... I replaced the TPS a few months ago ( a mechanic thought it may be bad)... My Check Engine Light, lit up, but turns off after 40mph.

Code 22 - Error Signal low..... I replaced it with the old one ( for today).. The Check light is doing the same thing with old one, but worse than before ( it didn't do that before)

I will get a Delco this time... BUT, could there be another cause for a "low signal"????

I also noticed the bolt holes are actually slotted. Is there an adjustment by tilting it a bit? Huh??

kennyhammond · 06-20-2017, 09:09 PM

Or good on this ..haven't messed with chevy trucks in a bit but if I am remembering right you should use a volt meter and the slots are for adjustments

mountie · 06-20-2017, 11:11 PM

Quote:

Originally Posted by kennyhammond

Or good on this ..haven't messed with chevy trucks in a bit but if I am remembering right you should use a volt meter and the slots are for adjustments

Something I need to learn about ( adjustment)

volt meter... I'm a fool with that tool....

Thanks

mountie · 06-21-2017, 07:24 AM

TPS school..... I read the directions (duh)...
My TPS has bolt hole slots for adjustment. Using a volt meter, you "tilt" the TPS to get between 0.5 & 0.8 volts. Then tighten.

Which way to tilt to raise voltage ( signal)?? Do you tilt toward the front of truck, or rear of truck?

**Mr_Rich** · 06-21-2017, 02:21 PM

That's one of those things you tend to set and forget. What to do is get some extra terminals to piggyback/ jumper the plug. You don't need the engine running to set this voltage and some scan tools will read that voltage. I know OBDII scan tools work this way because I've used it numerous times when the throttle body was acting up on my 3T. The older trucks like my '89 were adjustable and newer trucks I think some people filed slots in the sensor for adjustments. I looked in a manual I have and it says the reading should be 0.525 +/- 0.75 volts. Helm manual says 0.60 V and below 1.25 V at idle with engine running.

mountie · 06-21-2017, 10:33 PM

This morning, I tried something... since the DTC code was 22, ( low signal), I figured the TPS needed to be tilted, to slightly move the arm, ( up the signal?)

It worked. My truck is running way better! It's not perfect, but it will hold me over until I get it "dialed in".

A TPS is a potent-meter (sp?).... it tells the engine how much air is needed to mix with the gasoline, as the throttle body opens or shuts.

06-20-2017, 08:45 PM	#1
mountie Registered User Join Date: Jun 2011 Location: Bradenton, Fla. Posts: 1,100	Throttle Position Sensor, "Huh"? 1988 C2500 5.7 TBI -GMC.... I replaced the TPS a few months ago ( a mechanic thought it may be bad)... My Check Engine Light, lit up, but turns off after 40mph. Code 22 - Error Signal low..... I replaced it with the old one ( for today).. The Check light is doing the same thing with old one, but worse than before ( it didn't do that before) I will get a Delco this time... BUT, could there be another cause for a "low signal"???? I also noticed the bolt holes are actually slotted. Is there an adjustment by tilting it a bit? Huh?? __________________ '70 GTO Midnight Blue '88 GMC Sierra SLE 392,000 miles-(2018) sold to Classic car shop in Germany. '93 Cadillac STS Black '93 Mercedes SL 500 Teal '86 Yamaha FZ750 - 15,000 RPM '86 Yamaha FJ1200 - Criminally Fast 2016 Ferrari 488 GTB, I drive it - don't own it. '05 GMC Yukon XL , SLT 4wd ( just purchased 2018)

06-20-2017, 09:09 PM	#2
kennyhammond Registered User Join Date: Nov 2010 Location: Texas Posts: 256	Re: Throttle Position Sensor, "Huh"? Or good on this ..haven't messed with chevy trucks in a bit but if I am remembering right you should use a volt meter and the slots are for adjustments

06-21-2017, 07:24 AM	#4
mountie Registered User Join Date: Jun 2011 Location: Bradenton, Fla. Posts: 1,100	Re: Throttle Position Sensor, "Huh"? TPS school..... I read the directions (duh)... My TPS has bolt hole slots for adjustment. Using a volt meter, you "tilt" the TPS to get between 0.5 & 0.8 volts. Then tighten. Which way to tilt to raise voltage ( signal)?? Do you tilt toward the front of truck, or rear of truck? __________________ '70 GTO Midnight Blue '88 GMC Sierra SLE 392,000 miles-(2018) sold to Classic car shop in Germany. '93 Cadillac STS Black '93 Mercedes SL 500 Teal '86 Yamaha FZ750 - 15,000 RPM '86 Yamaha FJ1200 - Criminally Fast 2016 Ferrari 488 GTB, I drive it - don't own it. '05 GMC Yukon XL , SLT 4wd ( just purchased 2018)

06-21-2017, 02:21 PM	#5
Mr_Rich Registered User Join Date: May 2006 Location: Santa Maria, Calif. Posts: 781	Re: Throttle Position Sensor, "Huh"? That's one of those things you tend to set and forget. What to do is get some extra terminals to piggyback/ jumper the plug. You don't need the engine running to set this voltage and some scan tools will read that voltage. I know OBDII scan tools work this way because I've used it numerous times when the throttle body was acting up on my 3T. The older trucks like my '89 were adjustable and newer trucks I think some people filed slots in the sensor for adjustments. I looked in a manual I have and it says the reading should be 0.525 +/- 0.75 volts. Helm manual says 0.60 V and below 1.25 V at idle with engine running. __________________ 1989 K1500 Chev. EC Original owner; some of the aftermarket parts I've installed are Borla headers, Hypertech chip, Edelbrock water pump, and a Stillen rear disc brake conversion kit. 2009 Hummer H3T 3.7L 5M (sold) 1997 K2500 Chev. EC 7.4L/ 4L80E 2018 Dodge Ram 2500 HD R/C

06-21-2017, 10:33 PM	#6
mountie Registered User Join Date: Jun 2011 Location: Bradenton, Fla. Posts: 1,100	Re: Throttle Position Sensor, "Huh"? This morning, I tried something... since the DTC code was 22, ( low signal), I figured the TPS needed to be tilted, to slightly move the arm, ( up the signal?) It worked. My truck is running way better! It's not perfect, but it will hold me over until I get it "dialed in". A TPS is a potent-meter (sp?).... it tells the engine how much air is needed to mix with the gasoline, as the throttle body opens or shuts. __________________ '70 GTO Midnight Blue '88 GMC Sierra SLE 392,000 miles-(2018) sold to Classic car shop in Germany. '93 Cadillac STS Black '93 Mercedes SL 500 Teal '86 Yamaha FZ750 - 15,000 RPM '86 Yamaha FJ1200 - Criminally Fast 2016 Ferrari 488 GTB, I drive it - don't own it. '05 GMC Yukon XL , SLT 4wd ( just purchased 2018)



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