1996 Black Box l29 7.4 to 0411 Swap

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09-15-2019
donf

1996 Black Box l29 7.4 to 0411 Swap

I picked up a new tow vehicle for the dyno, a 1996 C2500 with the 7.4 and GT5. Very low miles. I should probably just leave it alone! Ha ha. I will not do anything for at least a few months probably longer as the dyno is still busy this time of year. I am curious and looking around to collect bits - info and parts for the future. I found a few posts that recommend a different starting point than the express van for the base tune. Just curious if anyone has heard of this here. Here is one snipet from the efi live forum.

Quote:

There is a specific GM mexico OS that is perfect for what you want. Better than the VAN OS. I never ended up swapping mine so I dont have it but ask him for a starter tune on the mexican truck OS.
09-15-2019
Fast355

Quote:

Originally Posted by donf

I picked up a new tow vehicle for the dyno, a 1996 C2500 with the 7.4 and GT5. Very low miles. I should probably just leave it alone! Ha ha. I will not do anything for at least a few months probably longer as the dyno is still busy this time of year. I am curious and looking around to collect bits - info and parts for the future. I found a few posts that recommend a different starting point than the express van for the base tune. Just curious if anyone has heard of this here. Here is one snipet from the efi live forum.

5.7 Van operating system would work out ok providing its not 4x4. If its 4x4 with the 02 code you could also swap to the trans segment for a 1-ton 8.1 truck with 4x4. Finally you could always swap the EFI connection reluctor in it and pickup some L21 valve covers and use the 8.1 engine tune with the electronic throttle control turned off.
09-16-2019
donf

Thanks for the reply. I am really not needing to swap the computer, just gathering info out of curiosity. Right now the stock pcm runs the stock engine and trans just fine. There is no tunerpro rt capability to change the tune of the factory pcm correct? I have HP Tuners but it only supports the vortec PCMs from 98 and up. With HP tuners the scan tool part will show data and clear codes. I had the MAF unplugged changing heater hoses, and it cleared the code. The editor part will not even read the computer.
09-23-2019
donf

After doing some more research, I am not moving away from the original 1996 VCM. I was able to get my hands on the pinout spreadsheets from a few helpful people. What a great source of information! The problem is on the older 96-97 trucks, to keep the evap system operational 1998 and newer parts have to be swapped in. I was not really doing anything at this point to need the swap and don't feel like disabling the evap or finding a newer truck and removing all the evap parts and swapping those into the truck, just so I can mess with hp tuners.
09-23-2019
Fast355

Quote:

Originally Posted by donf

After doing some more research, I am not moving away from the original 1996 VCM. I was able to get my hands on the pinout spreadsheets from a few helpful people. What a great source of information! The problem is on the older 96-97 trucks, to keep the evap system operational 1998 and newer parts have to be swapped in. I was not really doing anything at this point to need the swap and don't feel like disabling the evap or finding a newer truck and removing all the evap parts and swapping those into the truck, just so I can mess with hp tuners.

You can keep the EVAP purge active, but disable all the monitoring. I did this on my 97 Express van. As soon as you start the van after a reflash it already shows "READY" on the evap system as well.

I use Tunercats OBDII for the older black box PCMs.
09-23-2019
donf

So I am a little confused. This is what it says at the top of the 96 0411 swap spread sheet.

Quote:

3. The Evap canister vacuum switch that the 96 has is not supported by the 0411. The 96 does not have a Fuel Tank Pressure Sensor---Have the PCM programmed for NO Fuel Tank Pressure Sensor, Unless you want to install a 98-2000 Fuel Tank Pressure Sensor and Charcoal Canister with its vent valve, to have a fully functional Evap System. 4. Hook the Pink wire of a 98-2000 charcoal canister vent valve to the leftover Pink wire of C1 pin 4 of the 96 PCM, and hook the White wire of the vent valve to connector C2 RED pin 45 of the 0411 PCM.

And lower in the sheet.

Quote:

BRN- Canister Vacuum Sw. on the 96. This switch is NOT SUPPORTED by the 0411. Tape this wire back into the harness.

If I leave the 96 vacuum switch unpowered, I am not sure how the system will work?

So what you are describing is not having it disconnected and keeping the newer PCM hooked up to the early 1996/1997 evap system and there is a work around? Thank you for the feed back!
09-24-2019
Fast355

Quote:

Originally Posted by donf

So I am a little confused. This is what it says at the top of the 96 0411 swap spread sheet.

And lower in the sheet.

If I leave the 96 vacuum switch unpowered, I am not sure how the system will work?

So what you are describing is not having it disconnected and keeping the newer PCM hooked up to the early 1996/1997 evap system and there is a work around? Thank you for the feed back!

The canister switch is for Evap pressure detection for OBD2 compliance. Hook the wire from the purge solenoid to the proper PCM pin. Disable all the codes for the pressure sensor, vent valve and evap leaks. The canister purge valve will open as commanded and you will never have an issue with evap leak codes. My switch was physically in place but the wire lead to the PCM was tapped back into the harness.
09-24-2019
donf

I will save that info for if/when I do decide to swap the pcm. Thank you for the help!