TPS Voltage
Thread Starter
Race Director
Joined: Jan 2002
Posts: 12,264
Likes: 88
From: O'Fallon Missouri
TPS Voltage
My LT1's TPS voltage at idle is 0.53, which is fine. However at WOT I can't seem to get more than 3.92 volts. Is this high enough, if not, how do I raise the WOT voltage? I have my throttle cable fully adjusted.
Burning Brakes
Joined: Oct 2002
Posts: 1,152
Likes: 1
From: Wichita KS
Re: TPS Voltage (STL94LT1)
The factory manual shows a 5 volt reference signal is applied, and that you should very close to 5V at WOT, did you check what voltage you have before the switch? Should be around 5V...If you have got 5V before the TPS and can only get 3.92 out of the switch at WOT then it's in the switch or it's adjustment..The factory model is not adjustable but Advance Auto Parts sells Adj models under the Sorenson brand. I can look up the PN if you end up needing it...
:seeya
:seeya
Burning Brakes
Joined: Oct 2002
Posts: 1,152
Likes: 1
From: Wichita KS
Re: TPS Voltage (STL94LT1)
Take the TPS off of the T-Body & check the voltage that way, use a flat-blade to turn the TPS & see if you can get 5V out...If you can't then I would get a new Sorenson TPS. I think it was only $25 it has slotted mounting holes molded into it.
:seeya
:seeya
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
Re: TPS Voltage (STL94LT1)
Thanks superlund, I will try that.
Its just the way LT1's are I think, at least the '94 - '96 ones.
[Modified by Lone Ranger, 9:00 PM 1/12/2003]
Burning Brakes
Joined: Oct 2002
Posts: 1,152
Likes: 1
From: Wichita KS
Re: TPS Voltage (Lone Ranger)
Not to be argumentative, but after I read your post I thought I would go back & double check my memory by replaying my Datamaster logs/scan files of the various acceleration runs I've made.
What my scans show are 4.5V at 96% throttle on my 95'....Oddly enough I didn't see 100% throttle, but then again I didn't look at all of my files just a couple recent ones & it's possible I didn't hit 100% on those runs...
:)
What my scans show are 4.5V at 96% throttle on my 95'....Oddly enough I didn't see 100% throttle, but then again I didn't look at all of my files just a couple recent ones & it's possible I didn't hit 100% on those runs...
:)
Thread Starter
Race Director
Joined: Jan 2002
Posts: 12,264
Likes: 88
From: O'Fallon Missouri
Re: TPS Voltage (superlund)
I pulled the TPS, rotated it by hand, and it recorded 5v. So the TPS is working properly. The problem seems to be that the throttle bodies travel is too short to idle at .54v and WOT at 5v.
I settled on .585v idle and 4.01v WOT. Before the adjustment I was getting .53v idle and 3.55v WOT.
I settled on .585v idle and 4.01v WOT. Before the adjustment I was getting .53v idle and 3.55v WOT.
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Burning Brakes
Joined: Oct 2002
Posts: 1,152
Likes: 1
From: Wichita KS
Re: TPS Voltage (STL94LT1)
I had a Holley T-Body that had the mounting holes improperly installed/machined the only way I could correct mine was with the Adj TPS, I wouldn't suspect that to be a problem on a stock T-Body.
I ran some more Datamaster log files last night & what I found was this;
Starting around 3.9V the percentage goes to 100% you can watch the pedal travel go on up to say 4.2V @ 100% then mine will max out at 4.57V @ 100% so in essence once the PCM sees 3.9 it is translating that to 100% or full throttle. Sounds like you found a good range, I'll look at my idle volts tonight...
:seeya
I ran some more Datamaster log files last night & what I found was this;
Starting around 3.9V the percentage goes to 100% you can watch the pedal travel go on up to say 4.2V @ 100% then mine will max out at 4.57V @ 100% so in essence once the PCM sees 3.9 it is translating that to 100% or full throttle. Sounds like you found a good range, I'll look at my idle volts tonight...
:seeya
Le Mans Master
Joined: Feb 2002
Posts: 7,858
Likes: 2
Re: TPS Voltage (STL94LT1)
Thats just it, the TPS itself will generate 4.5v or 5v when removed and twisted manually with, say, a screwdriver to the end-stop. But the throttle butterfly mechanism on the TB hits its own mechanical stop before the TPS gets to the high upper end to generate max voltage.
If adjust mine any closer to max idle voltage spec on the low end (to get the TPS as close to 4v as possible at the WOT end) it causes the IAC solenoid to initiate a reset each time the ignition key is turned on.
I've tried it every which way but loose and the best I can get on the voltmeter with test leads is about 3.92v.
If adjust mine any closer to max idle voltage spec on the low end (to get the TPS as close to 4v as possible at the WOT end) it causes the IAC solenoid to initiate a reset each time the ignition key is turned on.
I've tried it every which way but loose and the best I can get on the voltmeter with test leads is about 3.92v.
I pulled the TPS, rotated it by hand, and it recorded 5v. So the TPS is working properly. The problem seems to be that the throttle bodies travel is too short to idle at .54v and WOT at 5v.
I settled on .585v idle and 4.01v WOT. Before the adjustment I was getting .53v idle and 3.55v WOT.
I settled on .585v idle and 4.01v WOT. Before the adjustment I was getting .53v idle and 3.55v WOT.
Racer
Joined: Jul 2001
Posts: 253
Likes: 0
Re: TPS Voltage (STL94LT1)
The TPS has 2 slots. It actually wiggles forward and back - not twist like a normal potentiometer. Moving the top forward adjusts one end of the voltage (low?) and the bottom adjusts the other end of the voltage (high?)
So, loosen and wiggle! :crazy: You should be able to get your 4.65V WOT.
So, loosen and wiggle! :crazy: You should be able to get your 4.65V WOT.
