PFF - Pennock's Fiero Forum, PDA Edition

3800 NA PCM usable in a SC top-swap? (Page 1/1)

lou_dias

SEP 08, 01:09 PM

So my 3800SC sledomatic car was a top-swap to the SC from an NA engine.
The PCM comes up as 1998 Pontiac Grand Prix GT ... not GTP.

The engine does not run perfect. Can this PCM be programmed to handle the SC addon? Or do I need to source an actual GTP PCM?

Dennis LaGrua

SEP 08, 03:28 PM

quote

Originally posted by lou_dias:

So my 3800SC sledomatic car was a top-swap to the SC from an NA engine.
The PCM comes up as 1998 Pontiac Grand Prix GT ... not GTP.

The engine does not run perfect. Can this PCM be programmed to handle the SC add-on? Or do I need to source an actual GTP PCM?

If your PCM is the same as the PCM used on the SC engine, then the program for that model year 3800SC can be imported into your PCM. However, you state that the part number is different. The question is; does this part number just call out the same PCM with a different program or is the operating system protocol entirely different?

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 09-08-2021).]

ericjon262

SEP 08, 09:03 PM

most of the OBD2 V6 PCM's have fairly extensive cross compatibility, FWIW, I've run a 3400, with L67 3800 programming. the software you are using will make a huge difference in what you can make happen with the car.

HPT?

DHP?

EFI live?

Tunercat OBD2?

if you're using DHP, I highly recommend finding "Tiny Tuner" and using a 2002 GP L67 bin file, as it has way more tables available to modify compared to almost any other OSID.

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"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

cognita semper

lou_dias

SEP 09, 08:01 AM

My dyno guy who is also a tuner uses Tunercat.
I'll try to get a part # for my PCM.
Seems to run fine at idle. Doesn't even throw any codes. Just seems to pull timing often when I get on the gas pedal.

I plan on converting it to a 4 or 6 speed eventually. I hate automatics...

ericjon262

SEP 09, 08:57 PM

quote

Originally posted by lou_dias:

My dyno guy who is also a tuner uses Tunercat.
I'll try to get a part # for my PCM.
Seems to run fine at idle. Doesn't even throw any codes. Just seems to pull timing often when I get on the gas pedal.

I plan on converting it to a 4 or 6 speed eventually. I hate automatics...

tunercat OBD2 is fairly uncommon, that's not to say he doesn't have it, but it is very uncommon, as TC licensed the software to JET as the JET DST. I have it only because I bought a Roadrunner OBD2 years ago (man that was pricey...)

if you plan on converting to a manual, you need to set the transmission type in the PCM to 0 and wire in a "clutch anticipate switch" to pin C18(I think) for the PCM to get the most out of it. I'm surprised it's not throwing codes, the engine is consuming way more air than a NA 3800. For a car like a grand am, that never came with a 3800, I could see some merit to keeping the original OSID that came with the 3400, because it will communicate better with the BCM and other auxiliary components like the instrument cluster, for a fiero that has none of that, just get an L67 file( I would use an 02 grand prix file) and run it, it will be way closer to what you need out of the box.