Throttle body stop mod
TECH Resident
Joined: Nov 2001
Posts: 894
Likes: 0
From: Chicago, IL
Re: Throttle body stop mod It's been a while since I did this. If you have Autotap, bring up the TPS Voltage parameter and grind until you see 4.6 or 4.7 volts at WOT. Maybe someone can confirm, you don't want to go past that value.
Re: Throttle body stop mod I do this on my ported units. I know how much I take off to get too much so I can leave it adjustable with a set screw, since I set the TB's up on a Mill and cut the area down in about 3 passes.
4.7V is the max you can go to, but it probably doesn't need to go that far for a full 90deg opening.
Bret
4.7V is the max you can go to, but it probably doesn't need to go that far for a full 90deg opening.
Bret
Re: Throttle body stop mod The GM manual say the TPS DTC goes set at 4.65 VDC so you have to stop at 4.64 VDC max. It also says the closed throttle value should be NEAR 0.6 VDC. It doesn't say if it should be above or below that value so I set mine at 0.59 VDC. You need a Digital VOM to get this kind of accuracy.
Teching In
Joined: Dec 2002
Posts: 18
Likes: 0
From: Slapout AL
Re: Throttle body stop mod John,
I used the following info to do mine - it is from a post on this board by ND4SPD. Worked great.
Disconnect plug from TPS on opposite side of throttlebody. Pull back the rubber insulation so that you can place (3) small gauge wires in each of the (3) holes. Now you have to connect plug back to TPS but will have (3) wires sticking out. Turn on Ignition keeping wires separated (not touching one another). The 3 wires are for voltage, ground, and variable voltage. You need to hook the two voltmeter leads to two of the three wires. Hook one voltmeter lead to the blue (variable voltage) and the other lead to one of the other two wires. When you have this correct your voltmeter will vary from 0-5 volts when turning throttle blade manually. Now just grind stop and keep checking voltage with throttle held wide open to bumpstop until you reach desired voltage. I went 4.65vdc. Over 4.7 will set code so be conservative near the end. Mine went from about 78 deg. (4.41vdc) to about 90 deg. (4.65vdc) when done. If you have tcs you may have to adjust throttle cable length depending on how far you go with the bumpstop mod. I had to.
I hope this helps!
I used the following info to do mine - it is from a post on this board by ND4SPD. Worked great.
Disconnect plug from TPS on opposite side of throttlebody. Pull back the rubber insulation so that you can place (3) small gauge wires in each of the (3) holes. Now you have to connect plug back to TPS but will have (3) wires sticking out. Turn on Ignition keeping wires separated (not touching one another). The 3 wires are for voltage, ground, and variable voltage. You need to hook the two voltmeter leads to two of the three wires. Hook one voltmeter lead to the blue (variable voltage) and the other lead to one of the other two wires. When you have this correct your voltmeter will vary from 0-5 volts when turning throttle blade manually. Now just grind stop and keep checking voltage with throttle held wide open to bumpstop until you reach desired voltage. I went 4.65vdc. Over 4.7 will set code so be conservative near the end. Mine went from about 78 deg. (4.41vdc) to about 90 deg. (4.65vdc) when done. If you have tcs you may have to adjust throttle cable length depending on how far you go with the bumpstop mod. I had to.
I hope this helps!
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Verdad Gallardo Re: Throttle body stop mod You just take a tiny sewing needle or tiny push pin and push it thru the insulation of the blue wire to the TPS to get the output DC Voltage. You attach an alligator jumper to the needle or push pin and attach the other end of you jumper to the RED lead on your meter. No need to make up some complicated cumbersome connector jumper bypass assembly just to make one simple sense wire voltage reading.
