bad tps sensor?
bad tps sensor?
I have a 1985 camaro iroc-z with tpi, and my tps sensor with ignition on and reset computer reads 3.3 volts at idle position and 7.4 volts at wot position. Is my tps bad or have I over looked something? Supposed to be .54 volts and over 4.0 at wot right?
On Probation
Joined: Mar 2010
Posts: 466
Likes: 0
Car: 1989 Formula,1991 z28
Engine: 400 Vortec Hsr,496bbc
Transmission: TKO600,TH400
Axle/Gears: 9"4.10, 9"3.73
Re: bad tps sensor?
reseting computer wont do anything to the TPS...
you have to move/adjust the TPS itself...
put a DVM on the middle wire on the connector, and check its voltage at idle..should be .50 to .60, slowly open throttle, watch for voltage spikes..it should be a smooth transition to 4.3+ volts.
if you are unable to acheive this, the TPS is bad...or the ground is faulty.
you have to move/adjust the TPS itself...
put a DVM on the middle wire on the connector, and check its voltage at idle..should be .50 to .60, slowly open throttle, watch for voltage spikes..it should be a smooth transition to 4.3+ volts.
if you are unable to acheive this, the TPS is bad...or the ground is faulty.
Re: bad tps sensor?
I have been moving it up and down and today I got it to read .5 volts. Then I slowly rotated it to full throttle and it didn't jump around at all but would only go to 2.54 volts at wot. Checked my ground and looked good. So tps is maybe bad? Thanks 89tbirdformula for the info.
Re: bad tps sensor?
Okay I bought a new tps sensor and put it on and set it at .54 volts and it is reading 2.34 volts at wot. I checked the ground that is bolted to the back of the engine and relocated it to the firewall. Still not reading correctly. Engine starts and runs fine for a few seconds, then starts running funny and my open headers start kicking out a blue flame. Very hot. So I shut it down within 30sec. Any other ideas?
On Probation
Joined: Mar 2010
Posts: 466
Likes: 0
Car: 1989 Formula,1991 z28
Engine: 400 Vortec Hsr,496bbc
Transmission: TKO600,TH400
Axle/Gears: 9"4.10, 9"3.73
Re: bad tps sensor?
Okay I bought a new tps sensor and put it on and set it at .54 volts and it is reading 2.34 volts at wot. I checked the ground that is bolted to the back of the engine and relocated it to the firewall. Still not reading correctly. Engine starts and runs fine for a few seconds, then starts running funny and my open headers start kicking out a blue flame. Very hot. So I shut it down within 30sec. Any other ideas?
the ground i was referring to checking was the actual TPS ground wire, but if you have .54 at idle, it sounds like its functioning fine.
Do you have the 02 hooked up? are all other sensors and vac lines hooked up? no vac leaks?
The TPS issue is odd, ive never really seen one read like that, check INPUT voltage to verify its getting the correct INPUT voltage{12+volts}, report back after ya figure that out.
Supreme Member
iTrader: (2)
Joined: Sep 2009
Posts: 1,591
Likes: 5
From: WI.
Car: 1987 iroc
Engine: 383 TPIS intake, Dyno Don headers
Transmission: 700R4 w/Pro-built Auto/transgo 2-3
Axle/Gears: 3.27/3.70 borg warner 9 bolt
Re: bad tps sensor?
Do you also have an o2 sensor?, you said you have open headers with blue flames. I set my tps at between .62-.65, cars throttle response is much better. Sorry , i typed this 1 min. after 89fbirdformula?
Supreme Member

Joined: Jan 2003
Posts: 2,043
Likes: 3
From: San Diego
Car: 1994 Trans Am
Engine: LT1
Transmission: Auto
Axle/Gears: 3.23
Re: bad tps sensor?
Im so clueless when it comes to TPS, but wouldn't setting it to a different setting than stock throw a code? And wouldn't a bad TPS throw an SES light?
Please somebody school me.
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Supreme Member
iTrader: (2)
Joined: Sep 2009
Posts: 1,591
Likes: 5
From: WI.
Car: 1987 iroc
Engine: 383 TPIS intake, Dyno Don headers
Transmission: 700R4 w/Pro-built Auto/transgo 2-3
Axle/Gears: 3.27/3.70 borg warner 9 bolt
Re: bad tps sensor?
You can run a TPS between .54 and .75 with no problems. By raising mine to .65 it feels more crisp, and also helped with a problem code 33 i was getting from my MAF. You don't gain anymore power just a crispier response. As for codes, you would see a code 21 or 22 if the voltage is either to high or to low. The only way to test if was bad is to use a digital VOM and watch your voltage run smooth up to WOT.
Supreme Member

Joined: Jan 2003
Posts: 2,043
Likes: 3
From: San Diego
Car: 1994 Trans Am
Engine: LT1
Transmission: Auto
Axle/Gears: 3.23
Re: bad tps sensor?
You are within .20 over. So could it not set a code if it was within .20 under? You said it's crisper at .65 and not setting a code, so inversely, if it were set at .45 and performance was more sluggish, would it not set a code because it was within range?
Supreme Member
iTrader: (2)
Joined: Sep 2009
Posts: 1,591
Likes: 5
From: WI.
Car: 1987 iroc
Engine: 383 TPIS intake, Dyno Don headers
Transmission: 700R4 w/Pro-built Auto/transgo 2-3
Axle/Gears: 3.27/3.70 borg warner 9 bolt
Re: bad tps sensor?
You can run a TPS between .54 and .75 with no problems. By raising mine to .65 it feels more crisp, and also helped with a problem code 33 i was getting from my MAF. You don't gain anymore power just a crispier response. As for codes, you would see a code 21 or 22 if the voltage is either to high or to low. The only way to test if was bad is to use a digital VOM and watch your voltage run smooth up to WOT.
Re: bad tps sensor?
you were right 89fbirdformula, not getting a good 12v reading. switched out batteries and ran great. It was a brand new battery with a bad cell or something. I took it back and went with an optima. Thanks for all the help guys!
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Joined: Sep 2006
Posts: 63
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From: OHIO
Car: 83 CaMarO Z28
Engine: 383 stroker AFR heads 600hp
Transmission: 700r4 stage 3
Axle/Gears: 373 9"
Re: bad tps sensor?
I have a 88 with a 6cly 5speed wht should i set the tps volt to? .54 or whts crispier? Like .60?
Supreme Member
iTrader: (2)
Joined: Sep 2009
Posts: 1,591
Likes: 5
From: WI.
Car: 1987 iroc
Engine: 383 TPIS intake, Dyno Don headers
Transmission: 700R4 w/Pro-built Auto/transgo 2-3
Axle/Gears: 3.27/3.70 borg warner 9 bolt
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