Stock Engine Management

* The brain of the stock Syclone engine management is an ECM (Electronic Computer Module) #1227749. Beside the Syclone and Typhoon it was used in GM 88' 2.3L Quad 4 cars like Grand Am, Calais, Skylark and in 87-90' 2.0L turbo cars like Skylark, Skyhawk, Calais, Grand Am. The following picture from DIY-EFI.org shows the #1227749 with cover off.



It pretty easy to find at any junkyard or at ebay too. I'm not sure it's till available from GM, but it was around $250 if I'm right. The MEMCAL is a separate part number. The MEMCAL has two halves, one carries the EPROM which contains the computer software (Motorolla assembly code) and lookup tables while the other carries the ESC (Electroninc Spark Control) module. The following picture shows a MEMCAL with the protective blue cover off.



There were different versions under different part numbers representing the different EPROM versions. The following table is from the old SyTy.org site.

Scan ID	Delco ID	Part Number
3051	AXXA 3086	16163085
3961	AYBM 4052	-
3961	AYBM 4053	16164052
3971	AYBN 4175	16164174
8581	AWXJ 9137	16159136
831	BBZA 1576	16181575
841	BBZB 1580	16181579
0	DOAC 6502	-

The 'BBZB 1580' should be the current EPROM for our application. The EPROM is a 27C128. *

Aftermarket chips

If you want alter the performance of your truck, sooner or later you have to do some chipping. One way to buy a chip from an aftermarket supplier the other way to do you own. I'd suggest to buy one and start to modify it if you have the need. There are several chips available from different vendors, but there is only one which anybody should deal with. This is the so called Ultimate chip from the STG crew. This is a multichip, so you get several (actually 16) programs with this chip which you can select from.



* If you want to know more about multichips, you can get some more information here. Basically you will have a piggyback adapter which resides into the place of the stock MEMCAL, and carries the original MEMCAL on it's back. With the ultimate chips you also get a control box (brained with a PIC16F84A) with a LED display and push button, so you can select your program on the fly to choose from different boost levels and timing. The different versions of that chip were developed by the STG crew. * The ultimate chips are using a 2M EPROM (27C2001 for example). The earlier versions of the STG multichips (4-in-1, 10-in-1, 16-in-1) used the stock MAP sensor. The current version called the Ultimate requires a 3bar MAP sensor. You've to replace the stock 2bar sensor with #16040749. The sensor has the same physical parameters, so it fits perfectly into the stock location. Originally it was used in 89' Turbo TA, but only to supply information to the boost gauge. * Why do you need the 3bar? The stock 2bar can measure from 1bar vacuum to 1bar pressure. 1bar pressure is ~14.7psi which is the stock max boost. If you want to raise the boost toward this limit with the stock ECM still controlling it, you can do it but you will be blind. You won't know the exact pressure, so you won't be able to adjust your fueling etc. This is where the 3bar kicks in. It can measure up to 2bar pressure (~29.4psi) which is more than enough. This stuff required the editing of no just the lookup tables but changing the assembly code in the chip. * If you don't want the 3bar chip for some reason you can still get a 10-in-1 multichip from the same guys with similar features. You can get these chips from Atomic Rooster Autosport. Forget all the other chips. KB, Pitbull etc. They are all trash. * Big credits here to STG crew, especially Brian Green and Todd Austinson to put endless hours of development into this thing. *

Burning chips

* If you want to modify your chips you will need the following things:

• EPROM burner. Either you buy it somewhere for around $120-300 or build it for around $50 I choose to build one based on this design with the help of my buddy, LaciV. We get the PCB made and made the soldering ourselves. If you need the gerber a drill files for the PCB drop me a mail.
• EPROM eraser. Or lot of patience. ;-)
• Good knowledge of the stuff and a hex editor or a good editing software.
• Some 27C2001's.

* Some words about the editing software. There are a really good SyTy specific called Promgrammer. You can download it here. It's nice. Big thx to Bill Calcagno. If you want some less specific -and more expensive- you can still go with TunerCat. * If you start to editing the tables, start it slow. You can get your ticket to blownmotor city really easy. There are three type of elements there.

• Flags - they are switches
• Constants - single values
• Tables - group of values in relation to each other, could two or three dimensional

* I'd say start with the more simple stuff then go upward. For example the Ultimate's 'valet' and 't1-15' programs has the EGR enabled. Since I've removed my EGR I disabled it in these two programs. There are two values which you should change. Disable Malfunction Flag 32 (0x0036) and raise the Temperature Level for EGR Enable to a value which you will never reach. This is simple. BTW. With multichips the different bins are coming after each other, so you can slice it up the EPROM image to 128k slices and can edit them with Promgrammer. There is a quite good docs you should read. I wish it would been complete! *

Mild to Wild

If you are thinking about turbo upgrades sooner or later your fueling needs will point toward the stock 28.5lb/hr injectors. At this point you have three ways to choose from. * First you can go with a 3rd party engine management system like FAST (formerly SpeedPro) or Accel DFI. If you choose this way spare some serious money (around $2k at least) and you will need your calibration. With such a setup you can choose the wildest things. FAST is quit popular among the SyTy crowd, so you might be able to get a startup program. * Second you can get a new version of Ultimate from BG now. It will need 50lb/hr injectors, which according to BG will give you enough fuel up to ~600HP. This chip is not a final product now, but several guys are using it with no probs. You can get more information here. It has some nice features like open loop (O2 out of equation) programs, seven different fueling levels. You still have two (18 and 21 psi) boost levels to choose from. If you have a mild turbo, especially something from PTE, a solid buildup I'm quite sure this is the stuff for you. * Third way to do you own chipping. It's the hardest way, tons of work and time, but if you are tough enough you will have a totally customized configuration. If you want to do this, I still suggest to use BG's work as the basic point to start from. If you need more than 50lb/hr you will have to change the injector drivers in the ECM. The 50s are the largest high impedance injectors, above this you've to use low impedance ones, which the stock ECM has no support for. It can be made though. The stock ECM has two injector drivers, though only one is used. All six injectors are run from this driver. If you wanna go with low impedance (aka Peak&Hold) injectors you will need two Fairchild Semiconductor HUFA76429P3's. You have to desolder the injector drivers from ECM and resolder the new ones. You can easily locate them under a plastic piece. You want to reuse the little beads on the driver "legs". They are filtering out the high frequency noise. You also want to reuse the plastic piece. If you choose this way I'd still suggest to get the 50's Ultimate and use it as the starting point for your own chip. This way you can go up to 72's or maybe 83's. I still have to see a SyTy running such a setup, but there are a few guys in the development hell. Will follow these results closely. *

Additional ECM releated projects

Currently I'm working on two projects. First is a quite simple one. It's a knock sensor led on the console. It was made by Opie and you can find more information here. Here is the explanation from Opie: * "The knock sensor is simply a microphone. This audio signal goes into a set of electronics that turns it into a pulse. When knock occurs, you get one pulse. If knock occurs again, you get another pulse. As soon as the ECU receives a pulse it retards the timing and holds that retard for some amount of time. If the ECU receives another pulse while it is already retarded, then it will retard the timing even further. After the amount of time has passed, the ECU will slowly release the retard. So, with the LED, you are actually looking at the pulses. The LED will flash once for each pulse. If you the LED flashes multiple times (very fast flashes), then you have lots of knock. If the LED only flashes once, then it's a very small amount of knock." * The other project a bit more difficult. I want to add a wide band O2 to the truck with a led display. This project is based on the diy-efi.org wb kit, but I actually bought my kit from techedge. It's not an easy going stuff, but now you can get your built unit from them. Be advised to use the LM1086IT-ADJ regulator instead of the LM317T-ADJ. Beside the kit and the LED display you will need an #OS791 NTK O2 sensor. The same sensor was used in some lean burning 92-95' Honda Civic 1.5 VTEC. The part number is #36531-P07-003. You can get the sensor at The Parts Bin or at a Honda dealer. Anyway Dig hacked our ECM assembly again to be able to put the signal coming from the kit into the ALDL stream, so we can see it in Datamaster as the A/F ratio. Nice. * I gonna document these two projects when I finished with them. *