LS3 throttle body on a C5
09-23-2017, 10:06 PM
#2
Race Director
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2020 Corvette of the Year Finalist (performance mods)
C5 of Year Winner (performance mods) 2019
a knowledgeable tuner can make it work but it's just easier to get a silver blade ls2 throttle body in my opinion... I believe what it does is register over 100% throttle position when you go wot and trips into rep mode
09-24-2017, 03:41 PM
#3
09-25-2017, 12:10 PM
#4
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CI 6,7,8,9,11 Vet
St. Jude Donor '08
So,,,,, What are the SECRETS to making it work. Can you elaborate???
Bill
Bill
10-03-2017, 07:25 PM
#9
so. here is what yall have been waiting for. after many hours staring at wire diagrams and pinouts and checking with a multimeter the problem has been figured out.
so why does everyone say it doesn’t work? “cause it turns backwards”
after my research and testing and thinking backwards this is what i found.
tps 1 and tps 2 signal wires are looking for a change in voltage. as the blade opens, one is looking for a rise in voltage and the other is looking for a decreasing voltage.
since it is turning backwards the TAC module is receiving the opposite signals. so tps 1 and 2 signal wires need to be swapped.
second. the tac motor is pulse width modulated. + and - need to be swapped for the backwards rotation.
its that simple!!! lol.
and sorry for all you guys selling LS2 throttle bodies.
so why does everyone say it doesn’t work? “cause it turns backwards”
after my research and testing and thinking backwards this is what i found.
tps 1 and tps 2 signal wires are looking for a change in voltage. as the blade opens, one is looking for a rise in voltage and the other is looking for a decreasing voltage.
since it is turning backwards the TAC module is receiving the opposite signals. so tps 1 and 2 signal wires need to be swapped.
second. the tac motor is pulse width modulated. + and - need to be swapped for the backwards rotation.
its that simple!!! lol.
and sorry for all you guys selling LS2 throttle bodies.
The following 2 users liked this post by HPS MASTER TECH:
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vettered 94 (03-16-2019)
10-03-2017, 07:43 PM
#10
Burning Brakes
so. here is what yall have been waiting for. after many hours staring at wire diagrams and pinouts and checking with a multimeter the problem has been figured out.
so why does everyone say it doesn’t work? “cause it turns backwards”
after my research and testing and thinking backwards this is what i found.
tps 1 and tps 2 signal wires are looking for a change in voltage. as the blade opens, one is looking for a rise in voltage and the other is looking for a decreasing voltage.
since it is turning backwards the TAC module is receiving the opposite signals. so tps 1 and 2 signal wires need to be swapped.
second. the tac motor is pulse width modulated. + and - need to be swapped for the backwards rotation.
its that simple!!! lol.
and sorry for all you guys selling LS2 throttle bodies.
so why does everyone say it doesn’t work? “cause it turns backwards”
after my research and testing and thinking backwards this is what i found.
tps 1 and tps 2 signal wires are looking for a change in voltage. as the blade opens, one is looking for a rise in voltage and the other is looking for a decreasing voltage.
since it is turning backwards the TAC module is receiving the opposite signals. so tps 1 and 2 signal wires need to be swapped.
second. the tac motor is pulse width modulated. + and - need to be swapped for the backwards rotation.
its that simple!!! lol.
and sorry for all you guys selling LS2 throttle bodies.
I would THINK the TAC motor should still have the same polarity, otherwise how have people been able to get 88% on the LS3/LS7 TBs (word is people always manage to get the LS3/LS7 TBs to work at idle and part throttle but fail/reduced power mode at WOT)? If the TAC motor polarity is reversed, then wouldn't the motor operate in reverse of the ECU request (full open when commanded to close, close when commanded to open)?
Looking forward to clarification as I've got a conversion harness on the way and an LS3/LS7 TB sitting in the garage just itching to be used.
Last edited by ChrisLSx; 10-03-2017 at 10:21 PM.
10-03-2017, 07:56 PM
#11
maybe it will work with the tac motor wires in their original position.
i just know it works the way i have it 100%. it worked from the start. without the tuner adjusting anything for it.
i just know it works the way i have it 100%. it worked from the start. without the tuner adjusting anything for it.
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ChrisLSx (10-03-2017)
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hammer2006 (10-04-2017)
10-04-2017, 10:15 AM
#15
Instructor
so. here is what yall have been waiting for. after many hours staring at wire diagrams and pinouts and checking with a multimeter the problem has been figured out.
so why does everyone say it doesn’t work? “cause it turns backwards”
after my research and testing and thinking backwards this is what i found.
tps 1 and tps 2 signal wires are looking for a change in voltage. as the blade opens, one is looking for a rise in voltage and the other is looking for a decreasing voltage.
since it is turning backwards the TAC module is receiving the opposite signals. so tps 1 and 2 signal wires need to be swapped.
second. the tac motor is pulse width modulated. + and - need to be swapped for the backwards rotation.
its that simple!!! lol.
and sorry for all you guys selling LS2 throttle bodies.
so why does everyone say it doesn’t work? “cause it turns backwards”
after my research and testing and thinking backwards this is what i found.
tps 1 and tps 2 signal wires are looking for a change in voltage. as the blade opens, one is looking for a rise in voltage and the other is looking for a decreasing voltage.
since it is turning backwards the TAC module is receiving the opposite signals. so tps 1 and 2 signal wires need to be swapped.
second. the tac motor is pulse width modulated. + and - need to be swapped for the backwards rotation.
its that simple!!! lol.
and sorry for all you guys selling LS2 throttle bodies.
Last edited by Brackets; 10-04-2017 at 10:16 AM.
10-04-2017, 10:16 AM
#16
Burning Brakes
LS7 throttle bodies have brass blades. Silver blade TBs are LS2. You installed an LS2 TB which is why it was plug and play.
Last edited by ChrisLSx; 10-04-2017 at 10:18 AM.
10-08-2017, 03:27 PM
#17
Burning Brakes
so. here is what yall have been waiting for. after many hours staring at wire diagrams and pinouts and checking with a multimeter the problem has been figured out.
so why does everyone say it doesn’t work? “cause it turns backwards”
after my research and testing and thinking backwards this is what i found.
tps 1 and tps 2 signal wires are looking for a change in voltage. as the blade opens, one is looking for a rise in voltage and the other is looking for a decreasing voltage.
since it is turning backwards the TAC module is receiving the opposite signals. so tps 1 and 2 signal wires need to be swapped.
second. the tac motor is pulse width modulated. + and - need to be swapped for the backwards rotation.
its that simple!!! lol.
and sorry for all you guys selling LS2 throttle bodies.
so why does everyone say it doesn’t work? “cause it turns backwards”
after my research and testing and thinking backwards this is what i found.
tps 1 and tps 2 signal wires are looking for a change in voltage. as the blade opens, one is looking for a rise in voltage and the other is looking for a decreasing voltage.
since it is turning backwards the TAC module is receiving the opposite signals. so tps 1 and 2 signal wires need to be swapped.
second. the tac motor is pulse width modulated. + and - need to be swapped for the backwards rotation.
its that simple!!! lol.
and sorry for all you guys selling LS2 throttle bodies.
Looking at your picture, I see you have:
Pin A = Yellow (vs Brown for LS1/LS2 TB)
Pin B = Brown (vs Yellow for LS1/LS2 TB)
This is your reversed TAC motor wires (I do this, immediate "reduced power mode")
Pin D = Looks like Green
Last edited by ChrisLSx; 10-08-2017 at 04:10 PM.
10-08-2017, 03:59 PM
#18
Burning Brakes
I checked the outputs of TPS 1 and 2 with my LS3 TB on the car. The values were as follows:
TPS1
0% = 0.65V
100% = 4.37
TPS2
0% = 4.35V
100% = 0.59V
That's the same voltage readings as the LS1 and LS2 TB. So..... why doesn't this work?
TPS1
0% = 0.65V
100% = 4.37
TPS2
0% = 4.35V
100% = 0.59V
That's the same voltage readings as the LS1 and LS2 TB. So..... why doesn't this work?
10-09-2017, 07:01 PM
#20
Burning Brakes
Well, I'm at a loss.
Unless I'm missing something I have my (adapter) harness wired exactly like you have yours and it's an immediate "reduced engine power" state.
I have:
Pin A = TAC Motor Control 1
Pin B = TAC Motor Control 2
Pin C = Low Reference
Pin D = TPS 2
Pin E = 5V reference
Pin F = TPS 1
Unless I'm missing something I have my (adapter) harness wired exactly like you have yours and it's an immediate "reduced engine power" state.
I have:
Pin A = TAC Motor Control 1
Pin B = TAC Motor Control 2
Pin C = Low Reference
Pin D = TPS 2
Pin E = 5V reference
Pin F = TPS 1
Last edited by ChrisLSx; 10-09-2017 at 07:02 PM.