12200411 PCM swap for 1996 to 2000 GMT400 trucks

[Mschaffer92]

This may have been answered already but on tapatalk i couldnt find it. If i have a stock 350 with just a cai, and soon headers do i have to do anything to the 0411 to run it in the truck or am i fine?

Sent from fiberglass covered Galaxy S3

 

[silverado13]

you need it to be tuned

 

[1BadBowtie]

So I got mine installed and i noticed during the first ride that my speedo is 10 mph fast and that my truck seems to be drinking more fuel than usual. Also I have a Vehicle monitor unit in the overhead counsel and the Instant MPH is WAY off. Any ideas?

 

[great white]

Speedo is calibration for tires and gears.

Wrong road speed info will mess up shift points, lockup, fuel scheduling, mpg, etc.....

 

[1BadBowtie]

Speedo is calibration for tires and gears.

Wrong road speed info will mess up shift points, lockup, fuel scheduling, mpg, etc.....

How would one go about solving this problem?

 

[2000CCSB]

So I got mine installed and i noticed during the first ride that my speedo is 10 mph fast and that my truck seems to be drinking more fuel than usual. Also I have a Vehicle monitor unit in the overhead counsel and the Instant MPH is WAY off. Any ideas?

Ok. Well first. Im not sure why the speedo is off. Where did you get your 411?

Second its running a non learned tune and will most likely feel funning for the next couple weeks. It needs to learn your driving and you fuel trims.

3rd and most important that instant mpg in your overhead console well its now worthless. The 411 has different input than the black box did. Mine did the same thing.

If you can find one of the DIC (driver information centers out of an s10/pickup, blazer, bravada, jimmy and suck that came factory with the v6 and a 411 pcm. I think that should solve it. Im still on the hunt for mine.

Any more question post em up.

CrewCab Steve

 

[great white]

How would one go about solving this problem?

It's adjusted in the calibration file.

In layman's terms: you need someone to "flash it" with the proper information.

 

[great white]

Ok. Well first. Im not sure why the speedo is off. Where did you get your 411?

Second its running a non learned tune and will most likely feel funning for the next couple weeks. It needs to learn your driving and you fuel trims.

3rd and most important that instant mpg in your overhead console well its now worthless. The 411 has different input than the black box did. Mine did the same thing.

If you can find one of the DIC (driver information centers out of an s10/pickup, blazer, bravada, jimmy and suck that came factory with the v6 and a 411 pcm. I think that should solve it. Im still on the hunt for mine.

Any more question post em up.

CrewCab Steve

If you can get the serial II data to the DIC, it should work as it did before as that's the datastream it needs to display info.

All bets are off if it's a different protocol though....

 

[2000CCSB]

Im 99% sure that it is a different "protocol" something about pulses per second 400 to 800? I dont know exactly.
What I do know is mine reads 100% backwards. I floor it wot and I get 255 mpg I coast and I get 0. So I've been driving every where in 1st gear flat on the floor Bwahahahaha.

Good luck with this one. Hopefully more "experts will chime in.

CrewCab Steve

 

[great white]

Im 99% sure that it is a different "protocol" something about pulses per second 400 to 800? I dont know exactly.
What I do know is mine reads 100% backwards. I floor it wot and I get 255 mpg I coast and I get 0. So I've been driving every where in 1st gear flat on the floor Bwahahahaha.

Good luck with this one. Hopefully more "experts will chime in.

CrewCab Steve

If I were to guess, I'd say you're thinking PPM, or Pulse Per Mile.

That's the output of the VSS. The PCM takes the PPM, interprets it (IE: what the DRAC/VSSB did in earlier trucks) and comes up with the road speed. It will also interpret the PPM and output different signals depending on what a component needs. IE: cruise may be looking for a different signal than the PCM calibration, Speedo is looking for a different output, the DIC may be looking for another, etc.

Seems to me if I were designing a system, I would have all the components reading the same PPM signal, but....well....that's GM for ya....