91 TBI car.. stock 746 ECM, ANTT ... (watches as half the people leave becuse its TBI)


if i leave everything, including the stock electronic distrib, and put a carb on top, how will the car react.

the TPS, IAC, and injectors wont be connected.



will it still run spark?

basicly im trying to keep my computer controlled spark, and still run a carb.

 

BTDT, works like a charm. See paper that describes how it was done on the diy-efi site (w/a '7747).

RBob.

 

In a nutshell, yes...I think. There is a writeup somewhere on the DIY EFI board in the GMECM FTP site that describes using a 7747 for spark only control. Here's a link to it.
7747 for spark-only control

 

but does it apply to my 746??

 

Sure thing. The '8746 & '7747 ECMs share the same hardware platform. Only the firmware is different. As that paper also describes all of the spark timing parameters, there will be a difference in the actual bin/PROM addresses.

Check out the writeup, it tells which sensors were used, which DTC's were disabled, and in general how it worked out. It was actually kinda' funny watching the ECM go closed loop and try to adjust the fueling.

RBob.

 

im looking thru that, and all im getting from it is..... confused.


i guess what im asking is, what do i need to do to make it work?

 

Most of the paper covers how the SA control operates. The beginning part tells which sensors are used and which DTCs are enabled.

Disable the O2 (13, 44, 45) and the TPS (??) DTC's. Need the MAP, KNOCK, and Coolant (and IAT) sensors. The VSS & O2 was also used but not required.

Are you burning PROMs? If not, then you'll get a constant SES light.

It would work out better if the TPS was hooked up to the carb. So if you can do that. . .

Then bolt up the manifold & carb, regulate the fuel pressure down (w/a bypass regulator), and turn the key.

RBob.

 

im not directly burning them.... im sure someone i know online will burn a image for me if i give them the chip and file, but im still a newbie to DIY EFI....