TPS fault diagnosis test
Thread Starter
Drifting
Joined: Sep 2014
Posts: 1,579
Likes: 59
From: Trieste Italy
TPS fault diagnosis test
Just made a backprobe test on my 1995 tps...
black voltmeter pointer on grey tps connector wire, red voltmeter pointer on battery terminal, key on
Reading is 0.01 and stay there, no move on...
Can we say it's time to replace it?
black voltmeter pointer on grey tps connector wire, red voltmeter pointer on battery terminal, key on
Reading is 0.01 and stay there, no move on...
Can we say it's time to replace it?
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 413
From: WV
On your car the TPS is non adjustable, and the minimum is set by the ecm when you turn on the key...With key on the TPS should read around .6 volts, and while moving the lever to WOT the voltage should move up smoothly without any voltage drops up to around 4.5-4.6..If you meter isn't showing any movement , and the wires are hooked up right , then it's time to replace your TPS..
....WW
....WW
Last edited by WW7; Sep 24, 2015 at 07:33 AM.
Thread Starter
Drifting
Joined: Sep 2014
Posts: 1,579
Likes: 59
From: Trieste Italy
On your car the TPS is non adjustable, and the minimum is set by the ecm when you turn on the key...With key on the TPS should read around .6 volts, and while moving the lever to WOT the voltage should move up smoothly without any voltage drops up to around 4.6-5.0..If you meter isn't showing any movement , and the wires are hooked up right , then it's time to replace your TPS......WW
....WW
Le Mans Master
Joined: Aug 2007
Posts: 8,735
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From: WV
...WWPS...The .54 is for a L98 engine, the LT1 starts with a slightly different reading. You just want to have a smooth voltage progression with no dead spots or fluctuations as you move the throttle upward....WW
Last edited by WW7; Sep 24, 2015 at 07:41 AM.
Thread Starter
Drifting
Joined: Sep 2014
Posts: 1,579
Likes: 59
From: Trieste Italy
The reason I'm not familiar with what wires to hook to is because I always set mine with a scanner...Scanners are quicker......WW
PS...The .54 is for a L98 engine, the LT1 starts with a slightly different reading. You just want to have a smooth voltage progression with no dead spots or fluctuations as you move the throttle upward....WW
...WWPS...The .54 is for a L98 engine, the LT1 starts with a slightly different reading. You just want to have a smooth voltage progression with no dead spots or fluctuations as you move the throttle upward....WW
Anyway there are two strange thing
No possibility to get it lower then 0,60v this is full unscrew TB screw...
It won't go over 4,64 v as higher voltage
What I'm searching for is the right voltage to set lt1 Tps via TB screw
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 413
From: WV
If you have a 95 Corvette your TPS is "NOT" adjustable..You just screw it in and your finished...If your reading goes from .60 to 4.64 without the voltage dropping, then there's nothing wrong with your TPS......The only ones that are adjustable are on the older cars..You can screw the TB screw all day and it won't change the settings on the TPS..But you will mess up your idle adjustment...
... .WW
... .WW
Last edited by WW7; Sep 24, 2015 at 05:20 PM.
Thread Starter
Drifting
Joined: Sep 2014
Posts: 1,579
Likes: 59
From: Trieste Italy
If you have a 95 Corvette your TPS is "NOT" adjustable...You just screw it in and your finished..The only ones that are adjustable are on the older cars..You can screw the TB screw all day and it won't change the settings on the TPS..But you will mess up your idle adjustment....
.WW
.WWTHOUGH
screw on TB side moves shaft and blades as result it moves even tps on the other shaft side located
My problem is that screw was been messed
Last edited by Christi@n; Sep 24, 2015 at 05:24 PM.
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Thread Starter
Drifting
Joined: Sep 2014
Posts: 1,579
Likes: 59
From: Trieste Italy
here our friends mention about 0.64 v with minimum open throttle.
infact mine wont go under 0.6 v. but I can increase it a little bit tighting TB screw
Le Mans Master
Joined: Aug 2007
Posts: 8,735
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From: WV
https://www.corvetteforum.com/forums...lp-needed.html
here our friends mention about 0.64 v with minimum open throttle.
infact mine wont go under 0.6 v. but I can increase it a little bit tighting TB screw
here our friends mention about 0.64 v with minimum open throttle.
infact mine wont go under 0.6 v. but I can increase it a little bit tighting TB screw
....WW
Last edited by WW7; Sep 24, 2015 at 08:26 PM.
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
The PCM reads the TPS voltage when you turn on the ignition and saves that number and calls it "idle". It should be approximately 0.6 volts for non-adjustable TPS sensors.
Le Mans Master
Joined: Aug 2007
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From: WV
.
.
Last edited by WW7; Sep 25, 2015 at 05:31 AM.
Thread Starter
Drifting
Joined: Sep 2014
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From: Trieste Italy
do you know what need to do in order to get a minimum air adjustememt?
Race Director
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From: Anaheim CA
Thread Starter
Drifting
Joined: Sep 2014
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From: Trieste Italy
I've already try to this some months ago, but my idle no go under 850-900rpm
Race Director
Joined: Apr 2002
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From: Anaheim CA
Thread Starter
Drifting
Joined: Sep 2014
Posts: 1,579
Likes: 59
From: Trieste Italy
The reason is that at some point, TB shaft has a stop that is screw unconnected with it
So i can turn screw again and again but idle stay there.
This point that i would to call "zero" match 0,60v on TPS and 850-900 rpm
Last edited by Christi@n; Sep 27, 2015 at 05:15 AM.
Safety Car
Joined: Sep 2010
Posts: 3,752
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From: Indiana PA
Either your throttle body is too dirty to allow the throttle blades to close all the way...
Or, you have a small vacuum leak somewhere causing the higher idle...
Or, your ECM is commanding the IAC open too far for some reason
Or, your IAC is not acting correctly.
All except the first are easy to spot with a good scan tool.
Those plugs on on the throttle body so people don't screw around with them trying to fix it the WRONG way. Not a dig at you but I've seen that before on GM throttle bodies.
Dumb question does it idle at that RPM ALL the time? A/C on and off? In gear and not in gear? Hot and cold?
Or, you have a small vacuum leak somewhere causing the higher idle...
Or, your ECM is commanding the IAC open too far for some reason
Or, your IAC is not acting correctly.
All except the first are easy to spot with a good scan tool.
Those plugs on on the throttle body so people don't screw around with them trying to fix it the WRONG way. Not a dig at you but I've seen that before on GM throttle bodies.
Dumb question does it idle at that RPM ALL the time? A/C on and off? In gear and not in gear? Hot and cold?