No throttle after frame swap.

Hi guys. I recently decided to get my 2002 2wd v8 truck running after popping the motor 3 years ago. I found a decently priced 2000 v8 4wd truck with a bad body and decided to do a body swap instead of trying to pull all the 4wd extras out and swapping them over. Everything went together good and the truck will start with the 2wd ecu connected and everything works except the throttle now. The throttle actuator motor stopped doing its thing after the body swap. Does anyone know of there are differences in the ecu pinout that would keep it from fuctioning? Truck won't start with 4wd ecu, not sure why but from what I had read here prior I didn't think it would be an issue.

 

Welcome! I first suggest you read through @whodatschrome's build thread HERE. Very detailed and ongoing as we speak.

 

Hi there Snoods and welcome to the forum. I just swapped a 2000 engine and 4wd drivetrain into a 2004 2wd truck. I used all of the 2004 body and engine harnesses, so my swap went fairly smoothly.

I don't think the 2wd trucks had a "2wd ECU". I believe that the only difference is that a separate 4wd ECU module is plugged into the standard Tundra 2wd harness in order to control the 4wd bits and pieces. The 2000 and 2004 use the exact same 4wd ECU module.

Did you keep your 2002 wire harness installed during the swap, or did you use the 2000 harness? There might be differences between some of the ECUs between 2000 and 2002? I'd 100% make sure to use a 2000 ecu with a 2000 body and engine harness, and a 2002 with a 2002 body and engine harness.


So let me ask you this...if you unplug the 4wd ecu (down at the passenger side interior kick plate) from the harness, then the engine will run, but once it's plugged back in, it won't?

If the throttle actuator motor stopped doing its thing after the body swap, then maybe the 2000 harness and 2004 harness aren't the same? Or maybe the actuator motor has corroded from sitting for 3 years? I think 2004 was the first year for the drive by wire throttle...which i found out during my build. I had to swap the mechanical throttle body off my 2000 block and install a 2004 drive by wire TB.

 

@whodatschrome 2002 2wd ecu is marked 4x2 and 2000 ecu from 4wd truck is marked 4x4. Left engine and all wiring in frame so engine harness is 2000 4wd truck and body harness is from the 2002 2wd. 4x4 controller is plugged in and 4wd works correctly. All body and engine controls.work as well with the 2002 ecu plugged in. When the 2000 ecu is plugged in the truck will crank but not start and a few of the dash lights stay on even with the key out of ignition. I've tried actuators from both trucks and neither works now but the 4wd trucks actuator was working prior to starting the swap as it was a full running truck. I can't find a good pin diagram for the 2 ecus so I haven't been able to compare. I can't find a sure answer if anything in the body harness would cause the no start so I'm just trying to see if anyone else had a similar experience.

 

I guess i don't know where the 2wd ECU is located. Do you have any pics of yours? I never had to swap out any sort of ECUs whatsoever out of my 2004 2wd truck. All i did was plug in a 4wd control module (ecu) into the existing harness in my 2004 2wd truck.

The speedometer assembly is different between the 2000 and 2004 trucks. Some of the lights in my speedo were not working when i had a 2000 speedo hooked up to the 2004 harness. I think i also had similar issues with trying to reuse my 2000 4wd dash bezel with the 2004 harness?

You might end up having to remove the 2000 4wd engine harness that's currently in your 2002 truck? Though it takes some work, you might have to swap back in your 2002 2wd engine harness. Then remove the 4wd sub harness from inside the 2000's 4wd main engine harness. Then "simply" plug them back into the 2002 2wd harness. The connectors for doing that is located up at the back of the engine block (right below the rear coolant crossover tube)...you know, the difficult place to get to.