Silverado v6 to v8 swap
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Silverado v6 to v8 swap Swapped a 5.3 off a 2001 Tahoe into my 2007 classic Silverado originally 4.3 DBC , got the motor fully in mounted and all. I have the motor, it’s pcm, wiring harness and fusebox having trouble with the engine wiring, the underhood fuseblock c-2 blk connector from the 01 5.3 is not compatible with my original fuse box. Is there any way I can still wire in my engine? Does anyone have the diagram for the fuseblock i need. I saw a diagram out there but it’s different from mine. I’m thinking of finding both diagrams and repining the connectors. Should I go about doing this? Would it even work? My 5.3 also came with its fuse box but fuseblocks c1,c3,c4 are different from the 07 wiring aswell so I think I’d be easier to repin fuseblock c2 blk to get it working possibly?
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Joined: Aug 2018
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The wiring changed from 99-02 to 03+ and are not interchangeable. You need to find an engine wiring harnesses and matching ECU that matches your truck, as close as possible.
I did an L59 from a 2004 suburban on my 1999 V6 Silverado and had the same issue. I wound up not using the 04 ECU and engine harness that came with the engine. Had to source a separate harness and ECU from a 2000 Silverado from the wrecking yard.
LT1 swap has ECU pinouts for various years ECUs. See if you can find one maybe 1 year +/- compare to see if there's any difference.
Edit: oops, meant to reply to OP...☺️
I did an L59 from a 2004 suburban on my 1999 V6 Silverado and had the same issue. I wound up not using the 04 ECU and engine harness that came with the engine. Had to source a separate harness and ECU from a 2000 Silverado from the wrecking yard.
LT1 swap has ECU pinouts for various years ECUs. See if you can find one maybe 1 year +/- compare to see if there's any difference.
Edit: oops, meant to reply to OP...☺️
Teching In
Joined: Dec 2022
Posts: 20
Likes: 3
The wiring changed from 99-02 to 03+ and are not interchangeable. You need to find an engine wiring harnesses and matching ECU that matches your truck, as close as possible.
I did an L59 from a 2004 suburban on my 1999 V6 Silverado and had the same issue. I wound up not using the 04 ECU and engine harness that came with the engine. Had to source a separate harness and ECU from a 2000 Silverado from the wrecking yard.
LT1 swap has ECU pinouts for various years ECUs. See if you can find one maybe 1 year +/- compare to see if there's any difference.
Edit: oops, meant to reply to OP...☺️
I did an L59 from a 2004 suburban on my 1999 V6 Silverado and had the same issue. I wound up not using the 04 ECU and engine harness that came with the engine. Had to source a separate harness and ECU from a 2000 Silverado from the wrecking yard.
LT1 swap has ECU pinouts for various years ECUs. See if you can find one maybe 1 year +/- compare to see if there's any difference.
Edit: oops, meant to reply to OP...☺️
TECH Apprentice
Joined: Aug 2018
Posts: 383
Likes: 108
There's also a thread over there that shows how to open the ECU to see if it has the DBC driver. Some ECUs had them, even through they were DBW, but not all.
Are you set on DBC? I know everyone says they like DBC, but on my 06 Suburban DBW, I can't really tell the difference over my 99 DBC. At least not for daily driving it.
Teching In
Joined: Dec 2022
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Yes, that's supposed to be other option.
There's also a thread over there that shows how to open the ECU to see if it has the DBC driver. Some ECUs had them, even through they were DBW, but not all.
Are you set on DBC? I know everyone says they like DBC, but on my 06 Suburban DBW, I can't really tell the difference over my 99 DBC. At least not for daily driving it.
There's also a thread over there that shows how to open the ECU to see if it has the DBC driver. Some ECUs had them, even through they were DBW, but not all.
Are you set on DBC? I know everyone says they like DBC, but on my 06 Suburban DBW, I can't really tell the difference over my 99 DBC. At least not for daily driving it.
TECH Apprentice
Joined: Aug 2018
Posts: 383
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i’ve been asking myself that question a lot because of the problems i’m having trying to keep it dbc but i’d just really really like it to be dbc if by this time next week I cant figure it out i’ll just have to surrender to electricity lol I love that cable ontop of the intake.
I would say just do the easiest/fastest thing to get the thing running on the road again, then you can swap to whatever you want. I've never looked into making the gas pedal DBC to DBW, and if it's a reversible thing, so that may not be practical. I don't know for sure.
But getting a TAC module and electronic gas pedal should be pretty easy to swap in and off you go.
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Teching In
Joined: Dec 2022
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I thought the DBW change was due to the traction control feature on some trucks that had that option. The ECU is able to detect wheel slippage via speed/wheel sensors and controls engine throttle through the electric accelerator. Maybe in conjunction with the ABS module? I can't remember. You can't do that with DBC, that's why they switched.
I would say just do the easiest/fastest thing to get the thing running on the road again, then you can swap to whatever you want. I've never looked into making the gas pedal DBC to DBW, and if it's a reversible thing, so that may not be practical. I don't know for sure.
But getting a TAC module and electronic gas pedal should be pretty easy to swap in and off you go.
I would say just do the easiest/fastest thing to get the thing running on the road again, then you can swap to whatever you want. I've never looked into making the gas pedal DBC to DBW, and if it's a reversible thing, so that may not be practical. I don't know for sure.
But getting a TAC module and electronic gas pedal should be pretty easy to swap in and off you go.
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