4 cyl GM SFI ????

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

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

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.

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?

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.

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

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find it amazing that the more sophisticated engine would have less sophisticated EFI.

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It is interesting to note how changes were made to the powertrains over the years. SFI is used to produce lower emissions as it does little to add power. The LN2 was the base engine for several models so it's likely multiple carlines benefitted when it was "cleaned up" with SFI. '96 was a change year with the introduction of new OBDII standards and preparation for this change likely started years in advance in some cases. With the LD9 introduction coinciding with the start of OBDII it seems likely that it was designed to run clean enough without SFI. It also needed no EGR valve to meet NOx limits.

Some of the sensors required to make an engine OBDII compliant happen to be the same sensors required to make an engine SFI. Without accurate crank and cam position it's difficult to determine which cylinder is currently at TDC so you're not going to find many pre-OBDII "base" engines with SFI. Saturn engineers developed an ignition module which measured current flow through both spark plugs of a wasted spark pair. The cylinder requiring higher current was determined to be on the compression stroke and was the basis for the cam position signal. It's called Compression Sense Ignition and it may be possible to retrofit this to an older engine if you're in need of a cam signal.

Along with the Saturn engine you might find European GM engines that were SFI yet were not OBDII compliant. Opel / Vauxhall engines were available in SOHC and DOHC configurations in many models and I'm told some used Delco controllers. The 20XE, C20XE, and C20LET vehicles are listed as SFI. Holden in Australia plus Daewoo and Isuzu both sold vehicles with GM engines and GM controllers but they are not as well documented and few are "hacked" for tuning. One possibility is the GM Family II engines which were based on the 2.0 SOHC block also found in Pontiac Sunbird until the end of 1994 model year.

MEFI V controllers are designed to deliver SFI and may give you the flexibility you're looking for without full OBDII compliance. MEFI V controllers can be tuned using MEFI Burn software. You may find MEFI V controllers available for a reasonable price.

Thanks again 1P2M,
Good information all around. Saturn's Compression Sense Ignition is intriguing. Also, the MEFI controllers have some good possibilities but so far they do not look cheap. I need to find out which one best suits my needs and then see what I can accomplish toward landing a used one. Their relative simplicity is attractive.
Larry

Those L4big pcms for the 2.2ohv have, from GM, alpha N fueling except for a very few J Cars in 97 which have a speed density tune. I have the tune and a flex fuel tune for a 2000 2.2 s10. Its in hpt format. I can send it to you if you want it. Those pcms are have limited tuning options with not much defined in HPT or efi live. That being saif jbody.org is (was) the best source for the l4big pcm tuning.

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Those L4big pcms for the 2.2ohv have, from GM, alpha N fueling except for a very few J Cars in 97 which have a speed density tune.

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Is this confirmed? Is it all calibrations or only the LD9 Supercharger calibrations that were Alpha N? If the cals are Alpha N, what purpose does the MAP sensor serve?

I'm currently looking at a file titled 2000 Cavalier 12206042 which appears to be traditional speed density with one side of the VE table being MAP indexed and the other being RPM indexed. Is this wrong?

Edit: Now I see the issue. There is an idle table which is MAP indexed while the off-idle tables are TPS indexed. Interesting. I have a .bin flagged as a '97 Cavalier which I'd like to compare but it appears that HPT is not interested in loading it.

Thanks,

Jay,
I thank you for the offer but for the moment I'm going to pass on the files/tunes - until I decide if the L4big PCM is suitable for my application. I may change my mind sometime soon.
Larry