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TPS voltage

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Old Sep 2, 2025 | 12:42 PM
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BG1959's Avatar
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From: San Antonio, Tx
Car: 1989 IROC-Z, 1970 Camaro SS
Engine: 5.7
Transmission: 700R4
TPS voltage

Recently inherited a 1986 IROC and working out issues with it. It had sat for a few years before I got it. Trying to set TPS voltage but lowest it will go is .96v. Swapped out TPS sensor with same results. Throttle plate is closed. What am I missing?
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Old Sep 2, 2025 | 07:12 PM
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From: Milwaukee
Car: 92 Firebird, 77 Trans Am SE, 86 Z28
Engine: 5.7 HSR, T/A 6.6, empty
Transmission: T-5, TH350, T-5
Axle/Gears: 3.08 posi, 3.23 posi, 3.23
Re: TPS voltage

Test one without it being bolted to the tb, just connected to the wiring. Maybe its a limit in the range physically for some reason we can't see.
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Old Sep 2, 2025 | 07:19 PM
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From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: TPS voltage

Was minimum idle speed set before tps was attempted to be adjusted?
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Old Sep 2, 2025 | 07:26 PM
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From: Milwaukee
Car: 92 Firebird, 77 Trans Am SE, 86 Z28
Engine: 5.7 HSR, T/A 6.6, empty
Transmission: T-5, TH350, T-5
Axle/Gears: 3.08 posi, 3.23 posi, 3.23
Re: TPS voltage

Originally Posted by Tuned Performance
Was minimum idle speed set before tps was attempted to be adjusted?
xactly. The blades could be set too far open already
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Old Sep 2, 2025 | 08:36 PM
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Re: TPS voltage

Also check to make sure the arm on the TPS sensor isn't bent or something.
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Old Sep 3, 2025 | 11:07 AM
  #6  
BG1959's Avatar
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From: San Antonio, Tx
Car: 1989 IROC-Z, 1970 Camaro SS
Engine: 5.7
Transmission: 700R4
Re: TPS voltage

Originally Posted by aliceempire
Test one without it being bolted to the tb, just connected to the wiring. Maybe its a limit in the range physically for some reason we can't see.
disconnected the new one goes down to .62v, the old one was 1.6v disconnected
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Old Sep 3, 2025 | 11:08 AM
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BG1959's Avatar
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From: San Antonio, Tx
Car: 1989 IROC-Z, 1970 Camaro SS
Engine: 5.7
Transmission: 700R4
Re: TPS voltage

Originally Posted by Tuned Performance
Was minimum idle speed set before tps was attempted to be adjusted?
yes, blades are closed
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Old Sep 3, 2025 | 11:09 AM
  #8  
BG1959's Avatar
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From: San Antonio, Tx
Car: 1989 IROC-Z, 1970 Camaro SS
Engine: 5.7
Transmission: 700R4
Re: TPS voltage

Originally Posted by ULTM8Z
Also check to make sure the arm on the TPS sensor isn't bent or something.
Was just looking at that, tried some light filing on it to try and remove any corrosion build up
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Old Sep 5, 2025 | 08:53 PM
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From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: TPS voltage

.62 vdc is removed from the tb ? Grey wire is 5v ?
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Old Sep 6, 2025 | 01:36 PM
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Re: TPS voltage

What kind of meter is being used? Does it have a recent calibration label? Splitting measurements down to the millivolt range is no place for a "Boris" instrument that might be accurate to ±10V. That includes most of the automotive market tools, like the kind off the back of a roving ice cream truck, or those hanging on the wall at the parts chain stores that also sell oil treatments, synthetic car wash, and "Kamala-scented" air fresheners.

Last edited by Vader; Sep 6, 2025 at 01:41 PM.
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