As part of my turbo project I tried a sequential ECM (Serv # 1227148) with my batch fire EFI this past weekend. This ECM is used in the '86-'87 Buick turbo cars as well as the non-turbo 3.8L '86 Buicks and Oldsmobiles, and '89 3.8L Firebirds. A different "chip" (EPROM) is used in the ECM for the turbo application. This ECM, with the non-turbo chip in place, worked perfectly under all conditions. So, it is true that a sequential ECM will default to batch fire with the absence of a cam position sensor.

This is good news for two reasons. First, it provides a wider range of ECM's to choose from, but more importantly it means that I can use the turbo chip with this sequential ECM when I install my turbo. In fact I also tried a turbo chip in this ECM. It also ran great just as before until I floored it. At that point I got lots of black smoke. This too is good. It means that the ECM was supplying the necessary fuel that will be needed when the turbo is in place. Such a deal!


BBobbias@aol.com

Hi bob
does the turbo chip have a preset amount of increased fuel compared to the throtle position sensor?
I was looking at a fuel only controler that runs off of a tach signal, does yours have a ignition retard in it?

andrew wagner

Yes Andrew, it's my understanding that the turbo chip has a "fuel map" that provides for proportional enrichment after the throttle position sensor voltage reaches a certain level.

The ECM does not monitor boost so it doesn't retard spark based on the amount of boost. However, the ECM will retard the spark if knock is detected. For this you also need the Electronic Spark Control (ESC) module, knock detector, and 7-pin GM ignition module. The ECM also signals a wastegate solenoid that opens the wastegate when detonation is detected. I will be using all of this on my car. Of course, you could also use these ignition and wastegate features on a carbureted engine.

It's these features that allow a stock non-intercooled turbo Buick to run safely at 14 psi of boost on pump gas. As you know, it's detonation that blows head gaskets, not the boost. I don't see any reason why we can't take full advantage of all of these features on an EFI SL6, and the ignition features on a carbureted SL6. My initial concern about the SL6 mechanical tappet noise does not seem to be a problem. This is because the knock detector is tuned to detect only a relatively narrow frequency band.

Bob D



BBobbias@aol.com

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Bob - is the incremental fuel increased proportionately with increased throttle position or is it a 'step function' increase?

ahtoews@shaw.ca

Al,
I don't know the answer to that. But, my guess would be that if it were a step function, that the steps would be small. So, for all practical purposes I would think that the increase would be proportional.

Bob D



BBobbias@aol.com

just curious.......wouldnt the map sensor send needed signal to fine tune that fuel curve?

My set-up uses a MAF sensor (flow) as opposed to a MAP sensor (pressure). The MAF signal is one of the inputs that the ECM uses to control the amount of fuel. This is also dependent on other factors including the EPROM that is used in the ECM. A turbo EPROM provides for more fuel at full throttle than a non-turbo EPROM. Actually, so far there isn't any problem with my turbo project, and everything seems to be working as expected.

Bob D



BBobbias@aol.com

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Hmmmmm. Bob.......do I foresee a follow-up article?

Roger

GTS225@aol.com

We'll see Roger. At a minimum I'll keep you posted on the project. Writing an article isn't easy, and definitely not a summer thing, so don't hold your breath. One thing writing an article does do is force you to learn your topic, so it has advantages for the writer too.
Based on the quality of your posts I think you would write a good article. Maybe you could write something on your supercharger project and related engine build-up. Or even a short article on the fabrication of your EFI manifold and fuel rail.

Bob D



BBobbias@aol.com

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Awww, shucks, Bob.......quit trying to embarass me. I'll give it some serious consideration. Maybe a "companion" article to yours, say, documenting the actual fuel delivery system, from the tank to the injectors, from a "nuts & bolts" perspective.
It could cover what I do for a pickup, electric pump, filtering, and return bypass line. Hmmmmmm.....maybe.......let me do some more research.

Roger

GTS225@aol.com

Bob, where do you get a turbo EPROM ? The dealer's parts counter ? Not many turbo regals in the boneyards around here. Would an aftermarket (hypertech ect.)work too ?
motorhedfred


motorhedfred@yahoo.com

I got the chip (EPROM) that I'll be using with the 1227148 ECM from the "parts for sale" section of one of the Buick turbo sites. These stock chips are sometimes available when folks upgrade to aftermarket chips. Check out <A HREF="http://www.gnttype.org/discus/">http:// ... discus/</A>, <A HREF="http://www.turbobuick.com/forums/">http ... forums/</A>, and <A HREF="http://turbobuicks.com/">http://turbobuicks.com/</A>. You will also find a number of sources on these sites that burn specialized chips for these applications at very reasonable prices (Max Effort, Thrashers, Jay Carter, Modern Muscle Car, Joe Lubrant, Red's, Casper's). For example, the Thrasher chips are only $25. <A HREF="http://www.thrasherchips.com/">http://w ... ps.com/</A>. Some of these guys regularly post on the sites and you can ask them questions. And, from what I understand, have them burn custom chips. I'd stay away from the aftermarket chip manufactures that aim at a wider market.
I would advise that you use the 1227148 ECM that was used in the '86-'87 turbo Buicks, as opposed to the earlier 1226459 ECM, because you can also get this ECM from '86 Buick and Olds non-turbo cars. The 1226459 ECM was only used in the '84-'85 turbo cars. Also, there are many more aftermarket chips available for the 1227148 ECM, and some of the specialized scan tools won't work with the 1226459 ECM. As I found out last weekend, if you are going to do your EFI turbo in stages, you can also run the 1227148 ECM with the non-turbo chip until your ready to install the turbo. You wouldn't be able to do that with the 1226459 ECM. If you're going to go with a turbo I think you'll want one of the specialized scan tools. Check out <A HREF="http://www.turbo-link.com/tlink/scancha ... rt.html</A>.

Bob D



BBobbias@aol.com

Sounds good! Go for it Roger.

Bob D


BBobbias@aol.com