no throttle - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tbrown5079 · 02-17-2015, 11:38 PM

Time to get serious on this issue. On the final install and want to solve this b efore I put the fenders on. Engine starts up fine and runs smooth. In default mode ( fast idle ). No throttle. Check engine light goes out. No codes. Multimeter shows proper reading at throttle body but all the terminals at the pedal coming from the TAC read 6.9 volts. All of them. Tomorrow I will check all the terminals coming out of the TAC to see if it's in the harness. Also, I put a mechanical oil pressure guage in and the plug going to the ECM is just hanging there. Would this have been deleted in the harness and ECM tune? Could this cause the problem? I emailed wait4me performance but didn't hear back from them yet. Any suggestions?
Thanks
tbrown

Angryman117 · 02-17-2015, 11:45 PM

The engine will run just fine without the oil pressure sensor. Did the TAC module, pedal, throttle body and ECU come from the same vehicle?

tbrown5079 · 02-17-2015, 11:50 PM

The supplier said they did. A local reputeable company. The owner delivered it himself, one butt ugly night.

BR3W CITY · 02-18-2015, 02:33 AM

Quote:

Originally Posted by tbrown5079

No throttle.

NO throttle at all, like not even a single rev or anything?
Watch the throttle blades (intake off obviously). Do they click up and down to system-check when key on is applied?

Also, I put a mechanical oil pressure guage in and the plug going to the ECM is just hanging there. Would this have been deleted in the harness and ECM tune? Could this cause the problem?

I'd have to check HP tuners, most of the lights can be turned off... but all it does is trigger the oil light. It has no effect on anything mechanically of operationally speaking. If you don't have an oil light hooked up, you won't even know.

tbrown

I have a few suggestions above. Also tell me what year your engine is, and what style of DBW pedal you have (metal arm or plastic)

tbrown5079 · 02-18-2015, 02:05 PM

Ok here we go. Thanks for the responses on the issue. It is what I thought a 2007 4.8 Sierra engine but the harness is 2006 style ( 8 pins at throttle body. The pedal is all plastic. No it doesn't set the throttle plate when you turn the key on. Pulled the plug for the pedal from the TAC and have 6+ volts on every pin. Eliminates the harness. Checked the plug from the main harness and I have 12v at pin 2 ( should be 5v reference). No other pins have voltage or ground ( pin 15 is G104 and should be ground? ). Should I not expect other readings since it is not plugged in?

BR3W CITY · 02-18-2015, 02:19 PM

Well 2007 is a GenIV which doesn't use a Tac, 2006 is a GenIII (usually, 06 was the transition year). Big difference in how this gets solved.

What ECM do you have? If its a GenIV setup that TAC shouldn't even be there.

tbrown5079 · 02-18-2015, 02:56 PM

The ECM is a Delphi P26440. Server# 12602802

tbrown5079 · 02-18-2015, 03:49 PM

Also, what is this plug for?

BR3W CITY · 02-18-2015, 04:22 PM

I can't see the attached images unfortunately, my setup doesn't like displaying non-embed stuff for some reason.

ls1nova71 · 02-18-2015, 06:52 PM

2007 is the transition year. They had new body style trucks and what they called the Silverado classic which was the older body style. The classic will be a genIII and have a TAC module. Post a pic of your engine and one of your computer and we can tell exactly which one you have. But, that plug in the pic looks like a plug for the electric fans judging by the colors and since there are only two wires.

tbrown5079 · 02-18-2015, 10:14 PM

Here they are. Like I said, I think it is like the 2006 Sierra because it has 8 pins at the throttle body.

ls1nova71 · 02-18-2015, 10:58 PM

Does it have a 4 bolt throttle body??

Looks like a 3 bolt, so that would be a genIII. Are you sure you have 12v power to the TAC module? If it never moves, makes me think maybe you missed a power wire. Other than that, try wiggling the wires a couple of inches from the throttle body, they're known to break inside the insulation in that area

Super73 · 02-19-2015, 12:32 PM

What is in the tune?
Is it 100% stock other than VATS?

Things like disabling MAF can cause no throttle if other things are not adjusted.
Reducing torque management can also result in no throttle.

They will start, run, and some times not throw codes with the above.

tbrown5079 · 02-19-2015, 08:55 PM

Now that I think about it there was one wire that I thought was an option( besides the one 12v all time and 3 12v with the key). I will check that( out of town for the weekend) and let you know. That may be the power wire I missed.

tbrown5079 · 02-19-2015, 08:57 PM

Just a very mild tune.

Super73 · 02-19-2015, 11:25 PM

Find out if tq management was plaid with.

tbrown5079 · 02-20-2015, 10:11 PM

Tuner says the reduced engine power mode is caused from a throttle issue, not torque management. I will double check to see that all components match and the wiring to TAC and throttle body. Any other suggestions?

Super73 · 02-21-2015, 03:09 AM

Quote:

Originally Posted by tbrown5079

Tuner says the reduced engine power mode is caused from a throttle issue, not torque management. I will double check to see that all components match and the wiring to TAC and throttle body. Any other suggestions?

Reduction of tq management can create a no throttle in a dbw vehicle. I have had to fix it when tuning several c5 vettes and my wife's tbss. Keep in mind I have been tuning the gen 3/4 stuff since 2001.

tbrown5079 · 02-23-2015, 10:27 PM

OK, was in the garage tonight trying to make sense of this. It is a genIII, 3 bolts at throttle body and a TAC module. I have some pin outs I got from LS1 swap and I'm checking voltages and grounds at the plugs to the TAC. I have 12v at pin 7 like I should have but no ground at pin 15. Then I have 6.9 v at every pin coming out of the TAC going to the pedal except for 1. The ground is G104. Wouldn't this cause my problem? Or would it only be ground if it was plugged in? Where could I pick up a ground in the harness to jump to G104 to check to see if this helps? Just trying to get a direction here before I have to start buying parts to throw at it. It runs smooth but at fast idle. Nothing you do changes it. Thanks for your help!

ls1nova71 · 02-23-2015, 10:39 PM

All the power in the world isn't going to help if you don't have a ground. Try grounding pin 15 and see what happens.

BR3W CITY · 02-21-2015, 02:06 AM

What are you using to check codes? Usually a throttle mismatch or similar failure throws a TAC failure/throttle failure/component mismatch code. A dbw-tuned truck should throw that code on startup the second that the TB doesn't do the position check...and I wanna know why the ECM is essentially ignoring the TB/TAC/Pedal failed.

Does it run ok otherwise? There are certain idle settings that affect the TB% that wouldn't be working if that whole system isn't working.

chuckmc8 · 02-24-2015, 08:08 PM

Wow! That's awesome work from you guys that contributed to help identify this problem and offer the solution. Kudos to all of you!

**LockDoc** · 02-24-2015, 08:52 PM

Quote:

Originally Posted by chuckmc8

Wow! That's awesome work from you guys that contributed to help identify this problem and offer the solution. Kudos to all of you!

Yup, lot of team work there. Glad you got it sorted....

LockDoc

02-17-2015, 11:38 PM	#1
tbrown5079 Registered User Join Date: Feb 2007 Location: Blairsville, PA Posts: 301	no throttle Time to get serious on this issue. On the final install and want to solve this b efore I put the fenders on. Engine starts up fine and runs smooth. In default mode ( fast idle ). No throttle. Check engine light goes out. No codes. Multimeter shows proper reading at throttle body but all the terminals at the pedal coming from the TAC read 6.9 volts. All of them. Tomorrow I will check all the terminals coming out of the TAC to see if it's in the harness. Also, I put a mechanical oil pressure guage in and the plug going to the ECM is just hanging there. Would this have been deleted in the harness and ECM tune? Could this cause the problem? I emailed wait4me performance but didn't hear back from them yet. Any suggestions? Thanks tbrown __________________ tbrown's 56 Cameo Build

02-17-2015, 11:45 PM	#2
Angryman117 Registered User Join Date: Jul 2013 Location: VAFB, CA Posts: 227	Re: no throttle The engine will run just fine without the oil pressure sensor. Did the TAC module, pedal, throttle body and ECU come from the same vehicle? __________________ Angryman117's 47 Chevy Build 89 Silverado Z71 LS Swap (sold)

02-17-2015, 11:50 PM	#3
tbrown5079 Registered User Join Date: Feb 2007 Location: Blairsville, PA Posts: 301	Re: no throttle The supplier said they did. A local reputeable company. The owner delivered it himself, one butt ugly night. __________________ tbrown's 56 Cameo Build

02-18-2015, 02:05 PM	#5
tbrown5079 Registered User Join Date: Feb 2007 Location: Blairsville, PA Posts: 301	Re: no throttle Ok here we go. Thanks for the responses on the issue. It is what I thought a 2007 4.8 Sierra engine but the harness is 2006 style ( 8 pins at throttle body. The pedal is all plastic. No it doesn't set the throttle plate when you turn the key on. Pulled the plug for the pedal from the TAC and have 6+ volts on every pin. Eliminates the harness. Checked the plug from the main harness and I have 12v at pin 2 ( should be 5v reference). No other pins have voltage or ground ( pin 15 is G104 and should be ground? ). Should I not expect other readings since it is not plugged in? __________________ tbrown's 56 Cameo Build

02-18-2015, 02:19 PM	#6
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: no throttle Well 2007 is a GenIV which doesn't use a Tac, 2006 is a GenIII (usually, 06 was the transition year). Big difference in how this gets solved. What ECM do you have? If its a GenIV setup that TAC shouldn't even be there. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

02-18-2015, 02:56 PM	#7
tbrown5079 Registered User Join Date: Feb 2007 Location: Blairsville, PA Posts: 301	Re: no throttle The ECM is a Delphi P26440. Server# 12602802 __________________ tbrown's 56 Cameo Build

02-18-2015, 03:49 PM	#8
tbrown5079 Registered User Join Date: Feb 2007 Location: Blairsville, PA Posts: 301	Re: no throttle Also, what is this plug for? Attached Images __________________ tbrown's 56 Cameo Build

02-18-2015, 04:22 PM	#9
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: no throttle I can't see the attached images unfortunately, my setup doesn't like displaying non-embed stuff for some reason. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

02-18-2015, 06:52 PM	#10
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,119	Re: no throttle 2007 is the transition year. They had new body style trucks and what they called the Silverado classic which was the older body style. The classic will be a genIII and have a TAC module. Post a pic of your engine and one of your computer and we can tell exactly which one you have. But, that plug in the pic looks like a plug for the electric fans judging by the colors and since there are only two wires. __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html

02-18-2015, 10:14 PM	#11
tbrown5079 Registered User Join Date: Feb 2007 Location: Blairsville, PA Posts: 301	Re: no throttle Here they are. Like I said, I think it is like the 2006 Sierra because it has 8 pins at the throttle body. Attached Images __________________ tbrown's 56 Cameo Build

02-18-2015, 10:58 PM	#12
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,119	Re: no throttle Does it have a 4 bolt throttle body?? Looks like a 3 bolt, so that would be a genIII. Are you sure you have 12v power to the TAC module? If it never moves, makes me think maybe you missed a power wire. Other than that, try wiggling the wires a couple of inches from the throttle body, they're known to break inside the insulation in that area __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html Last edited by ls1nova71; 02-18-2015 at 11:07 PM.

02-19-2015, 12:32 PM	#13
Super73 Registered User Join Date: Nov 2007 Location: Bay Area, Ca Posts: 2,841	Re: no throttle What is in the tune? Is it 100% stock other than VATS? Things like disabling MAF can cause no throttle if other things are not adjusted. Reducing torque management can also result in no throttle. They will start, run, and some times not throw codes with the above. __________________ ------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49

02-19-2015, 08:55 PM	#14
tbrown5079 Registered User Join Date: Feb 2007 Location: Blairsville, PA Posts: 301	Re: no throttle Now that I think about it there was one wire that I thought was an option( besides the one 12v all time and 3 12v with the key). I will check that( out of town for the weekend) and let you know. That may be the power wire I missed. __________________ tbrown's 56 Cameo Build

02-19-2015, 08:57 PM	#15
tbrown5079 Registered User Join Date: Feb 2007 Location: Blairsville, PA Posts: 301	Re: no throttle Just a very mild tune. __________________ tbrown's 56 Cameo Build

02-19-2015, 11:25 PM	#16
Super73 Registered User Join Date: Nov 2007 Location: Bay Area, Ca Posts: 2,841	Re: no throttle Find out if tq management was plaid with. __________________ ------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49



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02-20-2015, 10:11 PM	#17
tbrown5079 Registered User Join Date: Feb 2007 Location: Blairsville, PA Posts: 301	Re: no throttle Tuner says the reduced engine power mode is caused from a throttle issue, not torque management. I will double check to see that all components match and the wiring to TAC and throttle body. Any other suggestions? __________________ tbrown's 56 Cameo Build

02-23-2015, 10:27 PM	#19
tbrown5079 Registered User Join Date: Feb 2007 Location: Blairsville, PA Posts: 301	Re: no throttle OK, was in the garage tonight trying to make sense of this. It is a genIII, 3 bolts at throttle body and a TAC module. I have some pin outs I got from LS1 swap and I'm checking voltages and grounds at the plugs to the TAC. I have 12v at pin 7 like I should have but no ground at pin 15. Then I have 6.9 v at every pin coming out of the TAC going to the pedal except for 1. The ground is G104. Wouldn't this cause my problem? Or would it only be ground if it was plugged in? Where could I pick up a ground in the harness to jump to G104 to check to see if this helps? Just trying to get a direction here before I have to start buying parts to throw at it. It runs smooth but at fast idle. Nothing you do changes it. Thanks for your help! __________________ tbrown's 56 Cameo Build

02-23-2015, 10:39 PM	#20
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,119	Re: no throttle All the power in the world isn't going to help if you don't have a ground. Try grounding pin 15 and see what happens. __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html

02-21-2015, 02:06 AM	#21
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: no throttle What are you using to check codes? Usually a throttle mismatch or similar failure throws a TAC failure/throttle failure/component mismatch code. A dbw-tuned truck should throw that code on startup the second that the TB doesn't do the position check...and I wanna know why the ECM is essentially ignoring the TB/TAC/Pedal failed. Does it run ok otherwise? There are certain idle settings that affect the TB% that wouldn't be working if that whole system isn't working. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

02-24-2015, 08:08 PM	#22
chuckmc8 It's alsways something..... Join Date: Nov 2008 Location: Douglasville GA Posts: 1,171	Re: no throttle Wow! That's awesome work from you guys that contributed to help identify this problem and offer the solution. Kudos to all of you! __________________ 1968 RS Camaro 'Vert Matching number 327 and M21 Muncie 1968 C10 Black with red interior and orig paint. 5.3 / 4l60e,3:73 POSI 17" Torq Thrusts 1968 CST 514 Red with black interior. Buddy Buckets, Factory A/C, PS, PB- 20" AR custom shop TT, 5.3 and 4l60e

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