Hey guys, I just finished my 5.3/4L60e swap into my '69 C10. My motor is from a wrecked 2004 'Burb with 37k miles on the clock. Everything from the harness to the sensors to the DBW setup is all from the same 'Burb.

The stand alone harness and the PCM editing was all done by Wait4Me Performance. He removed all the emission stuff, VATS, etc.

Okay I finished up the basic stuff to fire the motor a few days ago and it fired up with the first turn of the key. Oil pressure is 50+ psi, no leaks, etc. When I tired to rev it alittle, nothing. Its like the pedal isn't there. I triple checked all connections, still nothing. I don't have an exhaust or front o2 sensors hooked up yet. The oil pressure port is being used for a manual pressure gauge. I've been told these connections shouldn't have anything to do with my DBW operation.

Yesterday I bought a scanner and pulled the codes. It displayed two, P0135 & P0155 which is because I don't have the O2 sensors hooked up. No other codes. I reset the codes and fired it up again, re-scanned, still no codes except the o2's.

By searching the forums I have read that the throttle body is suppose to 'cycle' when the key is turned onto the 'on' position. Mine does nothing, not a noise or movement, doesn't matter if the key is in the 'on' position or actually running, nothing. With the key off I can manually move the TB with my fingers and it opens and closes smoothly.

Last night I had my buddy who owns a 2004 Silverado stop by. Since his car is DBW also I wanted to confirm about the tb moving in the 'on' position. I watched it move about a half inch and stop. When running at idle his truck's tb moves all the time very slightly.

So, what do you guys think? Dead tb? Is it suppose to throw a code if the TB dies? What about the TAC or the pedal, are there codes for them?

Any help is thanked in advance.

 

When I did mine the throttle worked fine for about 3 days then died.Mine also came from a totaled '03 Silverado and there was some visible damage to the module.I went to a local junkyard and got another one from an '05 Tahoe and it's been working fine since.

Mine did have a trouble code and would "cycle" when I cleared it but did nothing else.

Maybe you could try or borrow a module or a pedal and swap yours out to see if that solves your problem before you buy one.

Good luck.

 

If you had a trouble code and you swapped out the TAC, I think it would be somewhat safe to thing that I don't have the same problem.

Based on what you are telling me I am leaning toward the TB being my issue.

Anymore else think so?

Thanks!!

 

The TB should blip like that regardless of whether the throttle pedal is working or not. I'd lean towards something TAC/TB/TPS as well..

Do you have the wiring data for the TB? I have it around here somewhere if not. I'd check voltages there. Is this the TB type with the separate TPS?

If they were working in the donor vehicle, you may want to ohm out the wiring between the PCM and TB (and TAC, if so equiped).

 

I don't have a wiring diagram. There is a single plug into the tb, so if it has a tbs I can't find it.

The donor vehicle was wrecked so I never saw it run.

Jesse at Wait4me says that he tested every plug/wire before it left his shop. But I guess its possible it was damaged in route back to me. It does have a TAC.

 

start with basics, check power / ground at the TAC module.

http://www.lt1swap.com/dbw.htm

There are some schematics for the DBW system at the above link.

 

Okay, I have ruled out the TB and the TAC module. A neighbor who has a 2004 'Burb let me test each of my parts by installing them on his 'Burb one by one by. All of them worked flawlessly on his truck.

So now its either in the harness or the PCM itself.

Can the DBW be deleted from the PCM during editing? I ask because it has been suggested that the DBW may have been accidentally deleted when I had all the mods done.

 

From what I have gathered they can add or take about anything out the ecu,I would contact whoever did it and see if you cant swing back by to have the flash checked. If it appears fine you may need do some un-looming to see if the harness has any hiddin damage.

 

I bought a milli tester and there is zero voltage coming out of the plug going to the TAC module. According to the wire diagram, the pink wire should have a igntion switched 12 volt, its doesn't.

 

I have a 2002 LQ9 and 4L80E in my trans am. I had the same problem. The engine would start and idle. I also didn't have any codes. When my pcm was flashed the programmer made a mistake and had it set for a cable throttlebody. 5 days later it was running as it should.

 

sounds like the harness is not providing the 12v+ switched power it needs. Even without the PCM hooked up or improper calibration on the PCM, the throttle blade will still move slightly when you initially turn on the power to it.


good luck.

 

I won't be able to mess with it until tonight around 7pm my time.

I think I will just jump the 12v to the pink wire to see what happens.

 

Okay, I installed the jumper and sure enough the tb cycles. However when I try and start the engine, it fires right up, then dies.

However, I did get the PCM to throw 2 codes: P0120 and P0220

P0120 - TP System Performance

P0220 - APP Sensor 2 Circuit

So, now what?

Thanks guys!!

 

P0120, GM Service info says is for Throttle Position Sensor 1 in the throttle body. TAC Module supplies 5v+ and ground reference to the sensor. The sensor is supposed to return a signal indicating throttle position. TP Sensor 1 voltage is low at closed throttle and high at wide open throttle.

P0120 will set when, TP sensor 1 voltage is less then 0.37 volts or grater then 4.51 volts. The PCM CAN command the engine OFF with this DTC set.

Looking at schematics posted in previous posts, DBW picture 1 of 2. TP Sensor 1 signal is a Dark Green wire. Check this circuit for opens or shorts from the throttle body to the TAC module. Pin 1 at the TAC module, Pin G at the throttle body.

P0220 is basically the same thing, only Senor 2 inside the throttle body. It too has a 5 volt ref, ground and signal back to the TAC module. Signal 2 is a Purple wire. Pin 11 at TAC module and pin F at throttle body.

Hope this helps. This seems to be a wiring issue, PCM is indicating the correct DTC's for a problem in the DBW.

 

Okay, at the request of Jesse at Wait4me I sent the harness back to him. I also sent the TAC module, throttle body, and gas pedal harness for him to test out.

 

And what was the diagnosis?

 

I had a bad ground on my end and the hot/switched wire for the TAC module was broken inside the loom. Jesse fixed the switched wire and told me to clean off any paint where the grounds connect to the block.

Problem solved.

Now I am running the same harness on a cammed LQ4 6.0 in my '75 Datsun 280z. Still works awesome.

 

Thanks for the update. I am trying to get all my questions and answers before I pull the trigger on a 5.3 4L65 swap into my 4X4 1972 Jimmy. I haven't seen any 4X4 swaps yet (not saying it hasn't been done I haven't seen it). I am keeping my NP205 and having an advance adapter output shaft and 6 bolt to 4 bolt adapter. I want to use DBW because it is on later lower mileage motors and it will be easier for cruise control later.

My crossmember and engine mounts might be an issue but should be workable. I am moving my engine 1 3/4 inches forward to keep my transfer case shifter in its stock location and to keep my almost new driveshafts. It will be close between the crossmember and the front differential but it is close now. I am hoping with adapter plates I can keep my crossmember where it is and just move the motor mounts back the 1 3/4? or maybe a little of both?

 

Trans-Adapt sell plates that mount the LSx motors EXACTLY where the SBC/BBC sat prior to the swap.