Is the PCM needed on a 3.9L F40 Swap?

[NateD4]

Does anyone know if the PCM is required to run the ECM on a 3.9L LZ engine?

I'm pairing it with the F40 manual. I am considering stripping the PCM harness from the main engine harness and tossing it.

I had heard somewhere that the PCM is still needed to run the engine for some reason even with a G6 6 Speed.

Can anyone confirm or tell me more about this?

[jman093]

PCM/ECM are the same thing, dude. You need it along with the entire GMLAN network bus system. To put it short you aren't swapping a 3.9L.

[NateD4]

I thought the PCM was the power train module for things like traction control, abs, stability track.

I have the harness and ECM (E3 but it's going in a car with an F40.

Can't the guys at EFI Live or HP tuners reflash an OS that doesn't need the other stuff on the CAN bus?

I thought there was a way to deactivate the theft system (aka startup polling)

[robertisaar]

there are a few 3.9 swaps that don't use the PCM it came with...

[pocket-rocket]

I thought the PCM was the power train module for things like traction control, abs, stability track.

The traction control and stability control might be in the PCM, but the ABS is not. Even something as primitive as my 92 has a separate computer for it.

[Joseph Upson]

Don't forget the BCM, the PCM will be looking for input from it.

[robertisaar]

The traction control and stability control might be in the PCM, but the ABS is not. Even something as primitive as my 92 has a separate computer for it.

if it's like the later OBD1 stuff, then traction control would be built into the ABS module to make a EBTCM (electronic brake and traction control module). not sure about stability control though.

[NateD4]

I'm not sure. I'd think it doesn't really matter since it should be able to run it either way. Just have to mess with the software.

[jman093]

there are a few 3.9 swaps that don't use the PCM it came with...

How are they controlling it without a factory PCM? 3.9's have VVT and some have active intakes while the others have DoD/AFM. Wouldn't this require a factory PCM to operate? That's why I thought you were working on a standalone way to control the VVT so that it could be controlled with megasquirt, etc.

[robertisaar]

How are they controlling it without a factory PCM? 3.9's have VVT and some have active intakes while the others have DoD/AFM. Wouldn't this require a factory PCM to operate?

depends on the build. some are using them in a locked position, others are using window switches to automatically advance/retard at certain points in the powerband, others are working on removing the VVT function entirely.

personally, i'm working on code to control both the VVT solenoid and the active intake using a rather common 16149396 PCM.

[jman093]

depends on the build. some are using them in a locked position, others are using window switches to automatically advance/retard at certain points in the powerband, others are working on removing the VVT function entirely.

personally, i'm working on code to control both the VVT solenoid and the active intake using a rather common 16149396 PCM.

Well that's kind of what I figured. That's pretty hokey shit. So nobody has ever done the swap and had it fully running. I'm not sure what the point would even be of doing the swap if that was the functionality you were living with. I would love to see you get that real swap up and running.

[robertisaar]

for some people, it was their only options.

for others, they didn't want the complexity of cam phasing.

me.... considering the 2006 G6 GTP w/F40 managed 18/29 with it and the 2006 Monte LTZ 3.9 accomplished 20/28 with a 4T65 w/3.29FDR, i'm fairly convinced the VVT system is a large part of their excellent fuel eocnomy.

it's an eventual item in the nAst1 project.

[Joseph Upson]

I'm not sure what the point would even be of doing the swap if that was the functionality you were living with. .

3.9L in a 60 degree package among other things is the point. It's cam in block phasing, not true VVT like that found in a DOHC engine with independent exhaust and intake phasing.

The G6 GTP owner I communicated with didn't get hwy mpg as good as my modified 3.9 motor (certainly not 29 mpg, maybe thats the 3500 G6) and my stock 3900 with the cam fully advanced got better mileage than it did so this form of VVT isn't that big a deal. The stock motor will be going back in before long so I can get an mpg test, the stroked motor got 30 mpg on the first test and about 80% of that test drive was in openloop at 13.2:1 afr so there was plenty of room for improvement.

[NateD4]

I will be doing a full vvt 3.9 plus DOD plus f40 swap. AND probably VGT turbo.

I'm curious about how you got over 30 mpg with a modified 3.9. I'm
Hoping for 32 in a Fiero.

As to getting it all running. I'm not sure of the big deal. HP tuner and EFI live give you all the control needed. I hear the E67 ecu is quite capable.