DBW - TAC Module Troubles - LS Swap - NEWB
09-30-2019, 02:41 PM
#1
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DBW - TAC Module Troubles - LS Swap - NEWB Reaching out for some assistance on a issue we are having on a project vehicle. The Drivetrain is from a 2004 Buick Rainier (5.3 - 4L60). The ECM has been sent to a tuner and the basic "Unlocking/tuning" has been completed. The Buick pedal would not work in our application due to the space requirements of the adjustable pedal assembly. A pedal and TAC module was sourced from a 2001 Yukon.
Prior to fire up, we verified changes in voltages being reported in the TAC (or ECM, not sure what module we were really looking at). We assumed things would be good to go.
Primed Oil System with no fuel (3 year old vapors in the fuel rail were spit and sparking)
Put fuel to the engine, fired up, idled at 300-400 RPM....Weird...No throttle input change to RPM
Pulled off intake verified no movement of the Throttle Body with or without the engine running. Only a random flutter, could manually move with the power removed.
Unplugged the TAC-ECU connector.
Fired up idle was normal around 800-900 RPM.
Upon further research, it looks like the pedal and tac module we are using is the solid Plastic version. The donor vehicle module is the Metal bracket version. My plan is to take a look at the pot values of the Donor pedal and the yukon pedal and see if they are the same, if so, rewire the 9 pin pedal to work as a 6 pin (i see the pinouts are different, going to pull better drawing of that from a dealer buddy this afternoon) and use the donor vehicle TAC module instead of the yukon.
The ECU was tuned with HP-Tuners, but the tuner is about 2 hours away. All i really have for diagnostic is a Snapon Apollo Scan tool and basic measurement tools (scope, DMM, Logic analyzer, etc {day job as a engineer})
No TAC related codes present.
Any feedback if my theory of the 6 to 9 pin pedal is going to work?
Prior to fire up, we verified changes in voltages being reported in the TAC (or ECM, not sure what module we were really looking at). We assumed things would be good to go.
Primed Oil System with no fuel (3 year old vapors in the fuel rail were spit and sparking)
Put fuel to the engine, fired up, idled at 300-400 RPM....Weird...No throttle input change to RPM
Pulled off intake verified no movement of the Throttle Body with or without the engine running. Only a random flutter, could manually move with the power removed.
Unplugged the TAC-ECU connector.
Fired up idle was normal around 800-900 RPM.
Upon further research, it looks like the pedal and tac module we are using is the solid Plastic version. The donor vehicle module is the Metal bracket version. My plan is to take a look at the pot values of the Donor pedal and the yukon pedal and see if they are the same, if so, rewire the 9 pin pedal to work as a 6 pin (i see the pinouts are different, going to pull better drawing of that from a dealer buddy this afternoon) and use the donor vehicle TAC module instead of the yukon.
The ECU was tuned with HP-Tuners, but the tuner is about 2 hours away. All i really have for diagnostic is a Snapon Apollo Scan tool and basic measurement tools (scope, DMM, Logic analyzer, etc {day job as a engineer})
No TAC related codes present.
Any feedback if my theory of the 6 to 9 pin pedal is going to work?
10-01-2019, 06:32 AM
#2
We just had a similar issue with space, for the pedal.
The system is out of a 2005 Suburban. The vehicle is a 55 Chevy.
The truck pedal is way too big. So, we used a pedal from a Vette, and swapped the module from the truck to the Vette pedal. It may be that you can do the same.
The 2 we used had the modules mounted w/ screws. A quik fix.
The system is out of a 2005 Suburban. The vehicle is a 55 Chevy.
The truck pedal is way too big. So, we used a pedal from a Vette, and swapped the module from the truck to the Vette pedal. It may be that you can do the same.
The 2 we used had the modules mounted w/ screws. A quik fix.
10-01-2019, 07:11 AM
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So... After ohmin out all of the pedal and coming up with what i thought was a better pin out... I went for broke. Pulled the 01 Yukon TAC module out and put in the Donor TAC connected the pedal and everything is golden.