1989 749 and 1990 707 have almost identical wiring

[BigBanks78]

Ok I bought a 749 off eBay and started collecting things to read about it and found a thread about a guy having hard time with a bunch of conveluted spark table, which is problem I'm having with 707. Lots of spark tables and lots of problems with spark.

Anyway I compared the wiring diagram from 1989 sunbird gt turbo to my 1990 grand am 707 and only diff I found was waste gate wire where 707 has a/c wire aldl wire one pin off fuel injector control had one wire down on diagram and 2 other wires were different but all wires were only 1 pin away except a/c control.

Does this mean mean I can use a 707 with same masks as 749 or just a coinsidence??

Im always grateful for any help!!!
Thanks everyone

[1project2many]

There is Quad 4 code that will work with both ecm's. There are differences in hardware which seem to prevent the 707 from working with the turbo Sunbird code.

[1project2many]

There is another wiring difference for some years / code masks. Some of the "not 7749 equipped" Q4 engines have an additional connection between the ignition module and the ecm. I believe, from memory, it is a 1X signal and if it is not present the code will not generate ignition pulses. I can try to get more details if you're interested.

[BigBanks78]

There is another wiring difference for some years / code masks. Some of the "not 7749 equipped" Q4 engines have an additional connection between the ignition module and the ecm. I believe, from memory, it is a 1X signal and if it is not present the code will not generate ignition pulses. I can try to get more details if you're interested.

Yea I would b interested but only if ur not doing anything else. I feel like I waste people's time on here cuz I've been screwing with this thing for almost 2 years and made so little progress, and really don't understand why I'm having so many problems. I can't watch knock cuz one knock make full retard until ignition is turned off and no matter what I do nothing stops it from going way lean when mat goes below about 90 degrees F. I'm going to try this 749 with code59 because more people use it and maybe easier for a luddite to use. It feels like I'm tuning a psycho woman, nothing u do pleases her and she turns complements into a nasty comment lol

anyway I'm searching and reading stuff to use this quad-4 ignition with the 749 and have been looking at a 59 bin from the syty s10 but I haven't read anything that says "this is how u do it" with the ignition and there's so many terms and words I have never seen before in that bin that makes me nervous !!!!

if u can remember off top of ur head any links that may help that would b cool but don't waste to much time cuz I may want to catch this thing on fire!!!!

[BigBanks78]

And THANK YOU!!! For all your help!!

[BigBanks78]

I got the 1227749 today and it has a AMDF MEMCAL but has 89 corsica written on the back. I looked up the wiring diagrams and could only find a 2.8 v6 with the 749 pin out.It says the v6 has the DIS on it, is there a problem using this DIS config or is it that the turbo software that doesn't like The DIS? I keep reading that theres some complicated wiring to do then add 60 degrees, minus 30 then move table to 18.?? for the total timing??

BUT!!! my diagrams do not say what ECM number.....