hbabler

iTrader: (1)

I have a 2002 5.3 that I installed in a 1971 IH pickup, I modified the harness and had the computer redone by lt1swap.com, this engine was out of a suburban and it is DBW, however it did not come with a TAC or TAC harness so I found those in the junkyard, they may be the problem although I am not sure. The truck starts and runs fine but the pedal is completely dead, I have checked the connections and wires visually and they are good, I have not installed 02 sensors or a MAF yet, and I am not sure what problems that would cause. I plan on getting a MAF today and seeing what that does. The codes are P0220 TPS switch B, P2135 TPS A/B Correlation, and the rest I believe are because of the missing MAF, P0102 MAF low volume, P0352D Ign coil B 2nd circuit malfunction, P1515 and P1516. If yall could give me any idea of what to check next that would be great. Thanks

93BlackBeast

iTrader: (31)

I have done three swaps now using DBW setup and have gotten pretty good at it through trial and error. When you say TAC module and TAC harness, I get confused unless you're talking about the pedal. The TAC module like you know is the black box usually on the firewall and the Pedal has the harness attached to it that plugs into the TAC module. Just clarifying.... As for TAC modules going bad, I've had my share of those too. In my swaps previously, I've had pullouts with motor and ECM, but they left the TAC and pedal out of it, so we had to do just what you said and go get our own. When I go to the junkyards, I picked up a couple of sets of them (matching sets, pedal and TAC module) and then tried them out in the swap when we got it running. Out of 3 modules, I had 1 that worked. One was dead completely like you are mentioning...no pedal response at all, motor is running fine. One was intermittent where the pedal would work until it went WOT and then quit completely. We'd have to unplug the TAC module from the PCM harness and then plug it back in to get it working again.. And btw, you probably know that you can check the functionality of them without the motor running...just key on and you can see and hear the throttle blade moving. And finally, the last one worked. The motor and PCM harness was from an 03 escalade and the pedal assy was from an 05 pickup...so I know the years don't have to match up exactly.

But anyways, to your questions about the MAF and other codes, they won't affect the TAC and throttle from functioning, so I'd start looking at taking that TAC/Pedal back to the junkyard and try finding another couple of sets to try out. I made a deal with my junkyard (who I used frequently and had a good relationship with) to let me try the sets and I'd bring back what I didn't use or what didn't work and pay for what I actually kept and he was fine with that. Because like I mentioned earlier, you don't know what you have with a TAC and pedal until you plug them up and try them. I don't know a good way to test them out either until you hook them up to a powered harness...so it kind of stinks. And again, when you do try them out, thoroughly test them out...because we didn't find out on that one that the TAC would quit working until we had it installed and driving it

But it's not the end of the world. Also, it's probably common sense, but when you're trying the new pedals and TAC modules out, you can just plug the TAC and pedal in without mounting anything and hold the gas pedal in your hand and activate it to see if it works...you don't need to go through the trouble of mounting it before trying it out....just stating the obvious. Simple things can get overlooked when you're focusing on other things and just trying to help save some time.

Good luck on the rest of the swap!

hbabler

iTrader: (1)

Ok I can add a little to the mystery now. I checked the TAC on another vehicle I have at work and it worked great, I tested the throttle pedal and the reduced power light came on and I had no throttle response just like on my IH. I purchased a new throttle pedal from my friendly GM parts guy and installed it on the truck this afternoon, I still have the same problem of no throttle response. I removed the new pedal and plugged it into the suburban at work and it now causes the reduced power light to come on and gives no throttle response. Could the harness between the TAC and the pedal be bad in such a way that it would kill the new pedal? I cannot afford to burn up another pedal if there is any chance this is the problem. Does any one have a pinout of what wires I am supposed to have going to the pedal and the associated voltages? Thanks for the help I think that I am getting closer to getting this figured out.

hbabler

iTrader: (1)

Never mind on the schematics I found some on LT1swap.com, I am still wondering if bad wiring could kill the new throttle pedal or if it was just a fluke that I recieved a bad one? Thanks for the help.

hbabler

iTrader: (1)

Anybody have any ideas? I am going to get a new pedal and I am a little aprehensive to install it.

busta9876

iTrader: (3)

Your codes point to a TPS problem, (throttle position sensor). Which throttle body are you using? Anything to do with the gas pedal will be shown as APP (accelerator pedal position)

psiconversion

iTrader: (5)

Do you have the stock truck throttle body (2 plugs, 6 pin and a 2 pin)? Does the TAC module you are using have a metal bracket or plastic?

FYI, I have never heard of the wiring ruining a pedal.

Jon
PSI

all juiced up

im having a similar prob if i stay easy on the pedal it works and it works when the motor isnt running but when i try and give it some gas the check engine light kicks on and then i have to turn the power off on the car and redo it also the car isnt tuned yet could this be the issue

Blazeracer

iTrader: (2)

Did this ever get resolved? I also have NO DBW pedal response with the MAF not in line, either unplugged or plugged in but the CAI not connected to the TB. No MAF, no pedal. I run HP Tuners, is there a work around for this?

warpdriv

I too am interested what came of this. I am having the exact same problem. I have put a new throttle body and TAC on, ohmed my harness between the TAC and pedal, and have tried a different pedal. I also checked the voltage at the ground points of the new PSI harness and that checked out.

Any help is appreciated. Thank you.