Re: OBDI Tuning
I'm a bit confused by this entire thread, but here's my $.02...
As others have noted, this isn't going to be a quick-n-dirty project... more like a years-long
ordeal. I know guys who spent 2-3 summers trying to cross breed an ECM.
Assuming you're willing to do what it takes, here we go.
For this particular application, I'm not sure why you *wouldn't* use a '749, considering they
came in '88 quad4 cars natively. The quad cars had some pinout differences from the Sunbird,
which I'm sure you've noted by now. You should be able to take the Sunbird pinout from
the gmecm web site and compare it to your stocker to determine which lines are the same, and
which are different. These are the lines you'll need to change once you convert.
If you want to have both sets of pinouts, you could fab yourself a "go between" adapter
that will allow you to plug both ECMs in, but it's a lotta extra work.
The '749 ECM and Sunbird code will run the Quad4 DIS, as I understand things. You'll
likely have to play with the timing values quite a bit in the chip calibration, but that's probably
the least of your worries.
I don't remember off the top of my head whether you said the vehicle is still running on the
stock ECM right now? If it is, there's a fair amount of testing you can do to validate
some of what you need to know.
The bit about the turbo quad4 bin: I have no doubt in my mind that there is one some-
where in the GM library, since there was one that came out of the GM raceshop. Even
if you did find it, it likely wouldn't be even close to your setup calibration-wise.
Start with the '749 ECM, get your pinout differences resolved first, then get a '749
with a Sunbird memcal (not a Syty) and Tunerpro to edit the chip. I would think that
the base sunbird bin should maybe start enough to get going. You'll probably need to
modify that Memcal for ESC to work properly, but that won't keep you from getting it
running.
The important differences in the two wiring setups are the fuel injector wiring (batch in
the sunbird and sequential in the quad) and the EST/ESC/ignition stuff.
Also, if you don't have a wide-band 02 setup, and you're at all serious about this,
get one. It'll save tons of time.
Also,
Read, read, read.
http://www.diy-efi-org/gmecm
Lots of guys have been down this road before... you can learn from their mistakes.
