Converted a V6 PCM to V8 but having issues

[Guyver280z]

I V8 swapped my girl's Astro van with a 2003 Tahoe 5.3 engine, unfortunately we didn't have the original PCM, so I got one from a truck at the salvage yard, I checked the serial numbers and made sure it was compatible, but it turned out it was V6 Silverado. So I downloaded an "OEM" 5.3 file from the repository and used the Compare tools to copy over all the differences, as well as removed the VATS and removed the drive by wire as well, wrote the PCM and plugged it on the van. But then the first try to fire up the engine, there was a backfire so violent that it cracked a hole on the intake manifold.

Is there a way to check if my PCM is correct? Like, can I upload the file to see if anybody can see anything wrong with it?
Nicki Astro V8 5-3 4x4.hpt

Also, there was a few parameters that didn't copy from the OEM file, but when I tried to manually change them I got a warning saying the "parameter is out of range"Comparison.jpg

Thanks for your help!!!

[blindsquirrel]

Are you asking if it's OK to upload the file when there's a sticky thread right at the top of this very forum that tells you to upload your file if you want help?

[SiriusC1024]

Go ahead and upload the tune as a .hpt file.

[kevin87turbot]

I've converted several V6 PCM's to V8 mode. I also loaded a V8 tune into it and used the "Write Entire" option. It's worked well every time.

[Guyver280z]

Go ahead and upload the tune as a .hpt file.

Nicki Astro V8 5-3 4x4.hpt

Here's the file, thank you so much!!

[Guyver280z]

yeah, sorry I didn't see the sticky. But thanks for pointing it out.

[Guyver280z]

Is there a way to rename it so it doesn't say "Silverado V6 anymore"? Also, Im a bit confused, if I change the VIN, will the license still work for the same PCM? I figured I could put the Astro Van's VIN just to make sure everything macthes correctly.

[Guyver280z]

I've converted several V6 PCM's to V8 mode. I also loaded a V8 tune into it and used the "Write Entire" option. It's worked well every time.

Is there a way to rename it so it doesn't say "Silverado V6 anymore"? Also, Im a bit confused, if I change the VIN, will the license still work for the same PCM? I figured I could put the Astro Van's VIN just to make sure everything matches correctly.

[blindsquirrel]

I don't believe the V6 file can be turned into a V8 file just by copying settings (although, possibly, with segment swapping every segment). If you want the whole roots-to-nuts (soup-to-nuts?) V8 operating system and V8 VIN and V8 everything you have to write the entire V8 file.

[Guyver280z]

I don't believe the V6 file can be turned into a V8 file just by copying settings (although, possibly, with segment swapping every segment). If you want the whole roots-to-nuts V8 operating system and V8 VIN and V8 everything you have to write the entire V8 file.

From my understanding it is part of the file, the part where you define the number of cylinders was changed to 8, what else is there to change? Screenshot 2023-11-06 155745.png

But at the end of the day, that's what I did, I copied the entire V8 file. But that's why I'm asking if anybody can help me look at the file to make sure everything is ok.

[blindsquirrel]

There's absolute tons and tons of code in the PCM that isn't defined with a table or drop-down box in the editor.

[SNAFU]

I downloaded an "OEM" 5.3 file from the repository and used the Compare tools to copy over all the differences, as well as removed the VATS and removed the drive by wire as well, wrote the PCM and plugged it on the van. But then the first try to fire up the engine, there was a backfire so violent that it cracked a hole on the intake manifold.

I just went through a nearly identical situation. I resolved my issues by finding a tune with the same Operating System # and performing a Segment Swap on the entire tune (all systems) and then ?write entire? when uploading the tune. This modified my V6 Blazer PCM to a 6.0 LQ4 w/4L80E truck PCM and my engine fired up with zero issues.

This segment swap method is also common when doing 4l60 to 4l80 swaps, except your basically doing a full vehicle swap, if that makes any sense.

Hope this helps you out!

[Onequickpuck]

Hey Kev.
Quick question, have you been successful with this method and been able to keep all the factory gauges and features fully operational? I am thinking of dropping an L31 Vortec in a '99 S10 Blazer 4x4 and just getting my head around all the electronics to make it look/work as factory. Thanks in advance!
Mike

[Alvin]

You'd be a lot better off if you could find someone to SPS your computer as a V8. I wouldn't assume a segment swap would be all you need. There are a lot of back ground things that HPTuners doesn't see/edit.

[kevin87turbot]

Hey Kev.
Quick question, have you been successful with this method and been able to keep all the factory gauges and features fully operational? I am thinking of dropping an L31 Vortec in a '99 S10 Blazer 4x4 and just getting my head around all the electronics to make it look/work as factory. Thanks in advance!
Mike

I've done several of those swaps. I've actually owned a few S10's that were swapped. I've never had a problem with flashing the V6 411 computers to a V8 OS. However, I do believe your 99 S10 Blazer has the ol black box ECU.

[Alvin]

I've done several of those swaps. I've actually owned a few S10's that were swapped. I've never had a problem with flashing the V6 411 computers to a V8 OS. However, I do believe your 99 S10 Blazer has the ol black box ECU.

I sorta forgot the application.. Yes on these computers an writing entire V8 calibration assuming the PCM is the same.