What If? $8D (1227727 ECM) for TBI

[dave w]

Here are some Schematics 1228708 Quad 4 and 1227727 4 Cylinder TBI. The scan quality is not the best; first I copied from a manual at my public library the scanned in as a .pdf.

dave w

[EagleMark]

Found this in Euorpe...

"For the first few years that I used a GMECM, to control my engine's ignition, I adapted and ran the $8Dsoftware - as it has probably the most commented, freely available hack (and it runs PFI - which is what I want#. Thehack includes the calibration data from the hacker's application #a V8 Chevrolet Corvette of the early 90's#, and isconsequently referred to by the Corvette chip name 'ANHT'. #Note: $8D was used for all GM 1990-1992 5.7 litre V8engines.# Despite the fact that the software was originally used for a V8, GM provided the ability for it to beconfigured to work for a 4 cylinder engine. A binary file, containing the whole of the original ANHT EPROM can bedownloaded by clicking here, and a disassembled 'hack', created by 'ECMGuy', can be found as a.PDF file here."

Unfortunatly the here links are now gone, but I do have the Corvette bin and diassembly set for 4 clyinder by ECMGuy...

ADDT.txt is a dissambled 2.0L 1227730

Seemed to have lost the other $3E for now?

[1project2many]

Ummm...
"ANHT for 4 cyl" is a stock turbo Sunbird cal.
0x0008 KKPGMID Program ID 0x58
0x0000 PROMID Prom ID Code 0x0D53 <-- Scan ID 3411

***Found!!!
BCC year is 1988
BCC= AUWR3607 Scan id= 3411 Part number= 16153405
Release date= 05/01/90 Engine size= 2.0 Trans Type= Manual trans
ECM/PCM: ECM #01227749
Used in cars: Pontiac
Possibly used in:
SUNBIRD SUNBIRD SE SUNBIRD GT
GRAND AM GRAND AM LE GRAND AM SE

Options:
With LT3 2.0L GAS 4 CYL MFI OHC TURBO
With MG1 MAN 5 SPD MUNCIE 76MM 3.50 1ST

[EagleMark]

See you can't believe everything you find on the internet...

[dave w]

I have not given up on this project. I am wondering, just wanting to make sure that a Quad 4 Memcal from a 1228707 can be used in the 1228708 ECM? I've interchanged Memcals from '7730 and 7727 so I've been thinking the memcals are interchangeable with the 1228707 / 1228708? The memcal BCC is ASDD

Thanks,
dave w

[1project2many]

Dave, the only correlating data I have is anecdotal posts stating the two ecm's are functionally interchangeable. There are a few posts on a Lotus forum where the guys successfully replaced one with the other because they are apparently hard to get in the UK. Another post by Ludis IIRC reports one is an underhood version of the other. All GM made memcals I've looked at have the same 28 pin Eprom, 14 pin and 16 pin backup fuel device configuration. All with a knock sensor appear to use the same connection points as well. But other than this "feel good" data, the only hard evidence we will have is when you are successful.

[dave w]

I think the course is going to change for this project. I think the option of a 4 barrel TBI similar to the one offered by Howell is something more to the liking of the original 8D / TBI idea.

dave w

[EagleMark]

Wow that looks expensive...

[1project2many]

FWIW that 4bbl TBI unit looks veeeery similar to one sold years ago by FIRST / AirSensors EFI. A small company in AZ named AutoNomics had all the old AirSensors TBI stuff for a while. Right now it looks like the TPI parts are being sold by First Fuel Injection. They may also sell the TBI parts. It's worth it to contact them. I bought a TB from AutoNomics for about $300. There are no injectors or rails and the IAC and TPS from a GM vehicle need to be added. IIRC when the company later started selling the TBs with these modifications the total price was around $500 which wasn't too bad. If the Howell price seems high this may be an option.

[dave w]

FWIW that 4bbl TBI unit looks veeeery similar to one sold years ago by FIRST / AirSensors EFI. A small company in AZ named AutoNomics had all the old AirSensors TBI stuff for a while. Right now it looks like the TPI parts are being sold by First Fuel Injection. They may also sell the TBI parts. It's worth it to contact them. I bought a TB from AutoNomics for about $300. There are no injectors or rails and the IAC and TPS from a GM vehicle need to be added. IIRC when the company later started selling the TBs with these modifications the total price was around $500 which wasn't too bad. If the Howell price seems high this may be an option.

I'll look into the information posted.

Thanks,
dave w

[dave w]

The final decision for this marine project is to use an underhood '7727 ECM with a used Edelbrock MPFI system, similar to the one pictured below.

I want to thank everyone for the information that has been posted in this tread!

dave w

[EagleMark]

I don't beleive the distributor or fuel pump is USCG approved for marine use. Remember gas fumes will lay in bottom of boat and you must turn blower on to vent engine compartment before startup. Any experianced boater will open engine hatch and look/smell for gas then turn on blower to vent hull.

Things like altenater and starter on boats do not have any exposed spark like a car. Cars fumes leak onto ground. Just be careful you don't install something non USCG approved for marine use... blow up boat... get someone hurt... liability... just a thought...

[1project2many]

^^^^ What he said!

Distributor can be modified by adding positive ventilation ala LT1 Opti. Use small ported fitting connected to TB and second larger fitting connected to air cleaner. Suggest to customer to spend saved money on proper marine EFI fuel pump.

Someday we can swap stories and I'll tell you about the distributor I accidentally launched out of a 5.9 Chrysler. :)

[dave w]

Agreed, Safety First!

Basically, I had been thinking many of the newer (mid 90's) Mercuisers were TBI V6 / V8? I figured maybe a marine 4.3 TBI distributor would need to be converted to V8, if a marine V8 TBI distributor did not exist. Looking online showed some promising marine V8 TBI distributor options.

dave w

[dave w]

I'm bringing this tread back from the past because I'm re-visiting the idea of a '7727 TBI again. This time, it's an Automotive application not a Marine application.

My question is:How do I get the Distributor Reference Pulse (DRP) to show up on an oscilloscope?

I have an old o'scope with dual channel. I have a complete test bench set up with a '7727 and TPI wiring harness. I am thinking I will set the Memcal to the correct cylinder select voltage for TBI, and use the O'scope to look at the DRP vs. Injector Pulse Width. The idea I have is to compare the TPI cylinder select DRP vs. Pulse Width against the TBI DRP vs. Pulse Width. I am thinking of using Noid Lights to load the injector drivers for the inital testing. Ultimately, I will install resistors with TBI injectors loading the injector drivers. Basically, I'd like to use $8D with TBI injectors (with resistors) firing at the correct TBI DRP. I expect an RPM limit of about 4200 RPM with TBI injectors and resitors?

All feedback / input is

dave w