First Fire, No Throttle Pedal Actuation

[Pontitruck]

Hey guys, it’s been awhile and I finally fired the 65 GMC up yesterday. It started no problem and it idled but I have no throttle pedal and P0120 and P2135 codes. Since the TAC module is under the seat with the computer and the pedal is loosely mounted I’m assuming I need to ground both of these. The interior is painted so do I need to run ground wires and or mount them to bare metal?
I have not checked but will later to see if there is a 5 volt reference at the TB.
The harness is BP and the rest of the set up is 2005 DBW.

Any other tips or testing?

Thanks!
Joe

[mongocanfly]

I like to use the external or internal tooth washers on all my ground points...I put the against the paint and the ring terminals on top..

[Pontitruck]

Originally Posted by mongocanfly

I like to use the external or internal tooth washers on all my ground points...I put the against the paint and the ring terminalson on top..

I use those too. Any input to the TAC ground question? Thanks

[mongocanfly]

I don't know...you could rig up some temp ground wires and see if it helps...I know you cant ever have to many grounds on a LS setup...I'm doing my 1st dbw LS now.....all my others were dbc

[bigmoe]

Does your pedal match your Tac? I tried to use a car pedal with a truck Ecm (Gen IV) and also got idle with no throttle up. It looks like both those codes are TPS related and maybe are pedal wiring related? Car and truck pedals can be interchanged by swapping two wires at the pedal plug.

[Pontitruck]

Originally Posted by bigmoe

Does your pedal match your Tac? I tried to use a car pedal with a truck Ecm (Gen IV) and also got idle with no throttle up. It looks like both those codes are TPS related and maybe are pedal wiring related? Car and truck pedals can be interchanged by swapping two wires at the pedal plug.

Well, the pedal came with the project but I didn’t get the TAC so I bought one for the same your as the drivetrain and ECM. How do I know if they are mismatched?
Thanks

[bigmoe]

Originally Posted by Pontitruck

Well, the pedal came with the project but I didn’t get the TAC so I bought one for the same your as the drivetrain and ECM. How do I know if they are mismatched?
Thanks

I had mounted a mystery pedal but I knew my Ecm was truck (gen IV doesn't have a tac) so I got a truck pedal from the wrecker and just mounted it to a piece of plywood, plugged it in and it worked fine. Once I knew my mounted pedal was a car pedal I found out on this forum which two wires needed to be swapped at the plug. If you can you should try to find out more if your tac and pedal are truck or car.

[bigmoe]

Here is my (car) pedal. The guy I got my engine and harness from had it pulled from a Tahoe by his hot rodder sons but he had no clue where the pedal came from. Some kind of car. The truck pedals are plastic and curvy and don't retrofit well.

[Pontitruck]

SThis project came with a pedal, which now I see is from Psi conversions where the harness came from. I did not get a TAC module so I chose one that said it fit what the drivetrain was out of. It’s an 05 5.3 and 4l60eor at least I thought I did.
I’m going to call Psi tomorrow to see if they will tell me what module goes with their pedal which is different than Bigmoes above.

[ls1nova71]

You don't need ground the TAC or pedal. It does seem like maybe you don't have the correct TAC. It should have a part number on it that will tell what year its for. Does the throttle body move at all when the key is first turned on? You should hear a slight click when the key is turned on, doesn't need to be started, but that will tell you if you are getting power to the TAC.

[Pontitruck]

Originally Posted by ls1nova71

You don't need ground the TAC or pedal. It does seem like maybe you don't have the correct TAC. It should have a part number on it that will tell what year its for. Does the throttle body move at all when the key is first turned on? You should hear a slight click when the key is turned on, doesn't need to be started, but that will tell you if you are getting power to the TAC.

Thanks Nova, I will check. I do have 5 bolts everywhere so that’s encouraging. Going by the pic below I found while searching, I have the right TAC (8923) for the style of pedal but it could be defective.

[Pontitruck]

Originally Posted by ls1nova71

You don't need ground the TAC or pedal. It does seem like maybe you don't have the correct TAC. It should have a part number on it that will tell what year its for. Does the throttle body move at all when the key is first turned on? You should hear a slight click when the key is turned on, doesn't need to be started, but that will tell you if you are getting power to the TAC.

TB cycles with the key.

[aknovaman]

Attach the HPT file from the PCM.

[Pontitruck]

[QUOTE=aknovaman;8786162]Attach the HPT file from the PCM.[/QUOTE


I sent it out and had it done, don’t have a file unfortunately.

[aknovaman]

check your pm.

[Pontitruck]

She’s alive, needed a throttle body. The other would cycle but that was it. No codes and the fans even come on when they’re supposed to. I’m psyched. Now to figure out how to hook up that darn neutral safety switch at the trans.
Thanks

[AussieinNC]

What transmission is in the truck?

If its an auto trans, there should be a factory NSS and reversing light switch on the side of the trans on the shift rod....(assuming you used a truck trans)

let us know what trans is in the truck.

[Pontitruck]

Originally Posted by AussieinNC

What transmission is in the truck?

If its an auto trans, there should be a factory NSS and reversing light switch on the side of the trans on the shift rod....(assuming you used a truck trans)

let us know what trans is in the truck.

Correct, it is a 4l60e with a range selector, the two harness type

[ls1nova71]

Originally Posted by Pontitruck

Correct, it is a 4l60e with a range selector, the two harness type

Do a search on here, I have posted how to wire the NSS up several times in the past.

[Pontitruck]

Originally Posted by ls1nova71

Do a search on here, I have posted how to wire the NSS up several times in the past.

Thanks Nova, I have all of your information.

[Pontitruck]

Originally Posted by ls1nova71

Do a search on here, I have posted how to wire the NSS up several times in the past.

Nova,

On your hand written schematic you have the wires numbered coming out of the range sensor as 1, 10, 11, and 12. How do it correlate that to the Circuit numbers on the harness? I have the old 2 wire style range sensor. Example, lt green is backup lamp supply voltage and is numbered circuit #24. I believe I only need to use Pins A, D, G, and E correct?

I hope that makes sense lol

[ls1nova71]

Here you go, just replace the numbers with the letters as follows, 1-G, 10-F, 11-C, and 12-E. Hope this helps.

[Pontitruck]

Originally Posted by ls1nova71

Here you go, just replace the numbers with the letters as follows, 1-G, 10-F, 11-C, and 12-E. Hope this helps.

Perfect! Thanks