4 cyl GM SFI ????

[lgrant]

All,
Can the 12200411 be configured to run a 4 cyl? Alternatively, is there a GM ECM/PCM (2002 vintage or earlier) that is SFI and native to the 4 cyl?
Thanks,
Larry

[dave w]

I'm thinking the Ecotec 4 cylinder computer is an option. https://en.wikipedia.org/wiki/GM_Ecotec_engine

Likely HP Tuners is the only option for software / hardware to read / write to a Ecotec 4 computer. https://www.hptuners.com/vehicles/

dave w

[lgrant]

Dave W, apparently you are correct or mostly correct. I paid a visit to the local PnP yesterday to see what GM hath wrought. Then after I got back to a keyboard, I did some learning.

I found some 1999 and 2000 Sunfires and Cavaliers (that were still intact) that had the 2.2L base engine and those engines reflected "2200 SFI" on the valve cover or intake or both (valve covers don't lie, do they?). I did not see anything with the more sophisticated 2.4L upgrade but presumably the better engine would have SFI if the cheap engine had it. Hptuners' website indicates that these vehicles are supported for model years 97-05. 05 was the end of the J car run. A digital tour through Rock Auto did not produce much useful info - between 97 and 05, there were several different ECM/PCM part numbers. For these J cars, the old school engines were used to some point in the 2002 model year and then totally phased out in favor of the 2.2L Ecotec.

So Hptuners looks to be a good resource. That said, anybody have a suggestion as to where to find documentation or a writeup on the GM J car/body fuel injection? It would be good to have some knowledge of the system(s) before contacting Hptuners.

[lgrant]

I got on the j-body.org board and did some reading. The PCM is apparently known as "L4BIG." Anybody ever heard of this?

First things first - can the firing order in GM PCMs normally be changed? I've read where the '0411 can be so I'm assuming that most can. Good assumption?

[1project2many]

Although Wikipedia reports the LN2 was SFI beginning in '94, the engine was not actually SFI in Cavaliers or S10's until 96 with the implementation of OBDII. In 2003 a 2.2L Ecotec engine was introduced along side the LN2 and both engines were used simultaneously until the death of the Cavalier.

I was on J-body.org years ago. At that time there were no nicknames for the pcms. I can see how it happened, though. The LN2 pcm (and the 2.4 DOHC pcm as well) was much closer to the 0411 pcm in size while the Ecotec used a very small controller.

The firing order is in the engine, not the pcm. The pcm triggers four injector drivers and two coil drivers but has no clue what they are connected to. Change the wiring, change the firing order.

The 2.4 is batch fire through the end if its life in the J-car. You can confirm this in wiring diagrams here:
https://www.autozone.com/repairinfo/...00c1528003cfdd

Are you attempting to switch a GM controller into a non-GM OBDII vehicle? If you are attempting to control a four cylinder that is not emissions controlled you may find an OBDI ecm is easier.

[lgrant]

Thanks 1P2M,
You've answered the firing order question and I thank you for that.

I did not analyze the autozone diagram but find it amazing that the more sophisticated engine would have less sophisticated EFI. Maybe it's a moot point in that in the higher RPMs, the batch fire is not appreciably different from SFI in end results - not enough time for the SFI to do its job.

Regarding OBDII vs OBDI, it appears that if one wants SFI from a GM 4 cyl application, you're locked into OBDII. Do I have that right or did I miss something?

Thanks for you response.
Larry