Here is what I have found out so far.

There are 22 pins on the 92 Fbody 7730 ECM that do not directly match the Sy/Ty 7749 ECM. some are trivial & some are not. for example on the 7730 the serial data comes out of A8 & on the 7749 the serial data comes out on A9. they are connected in the ECM so who cares.

the ones that seem really important are the Waste gate control & the TCC. on the 7730 the TCC in on F6 on the 7749 it is on F4. so no problem move the pin. you do now lose the canister purge solenoid. I would say that if you are going to go down this road either get rid of the cats or gut them (naturally this is for off road use only, I would not want to imply or suggest that you do this to a vehicle that is drive on state or federal roads or highways as that would be tampering with the vehicle emissions equipment that the general has so consciously installed into the fabulous automobile that you are currently in possession of (in one breath). Which one of the little guys is responsible for the legal disclaimers? please have him double check my work).

the Waste gate control output is on F2 on the 7749 & that goes to the Port Switch solenoid, again for the converter & that again goes to the smog stuff (Port switch solenoid). it is hanging on the front of the motor, never installed.

I am not using either of them so this is no major concern for me.

there are three other things of concern to me. first, my print shows that there is an input for fan number two but that there is not an output that controls it although I recall in GME Pro that there is a set point for it. my print shows that it pretty much is controlled by the AC High press switch & a thermostatic fan switch. neither of which my car have, but anyone that has a factory car & harness is/might have to address this issue. My take on it is to jumper the control line for fan 1 to fan 2 & be done with it. although, if you loose the ECM & go into limp home mode you are not going to have a fan.

second, the print that I have shows:

7749 7730
iac b low iac a high
iac b high iac a low
iac a low iac b high
iac a high iac b high

I don't know how the iac works (on/off, harder/softer), but the sunbird 7749 is wired exactly as the 7730, so I bet it does not matter.

So far no brainer, here is where I am stumbling. I searched the 3rd gen site but have not got to the diy or GMECM archives yet, maybe someone can shed some light on this or I am going to have to try out that new archive search engine (thanks to Bob Hughes, sp?). the 7730 has an input for VSS low & VSS high, the 7749 has a DRAC input. I seem to recall from about a month ago that the DRAC is an input signal from a "box" that is usually under a seat or dash & is essentially a translator for the vehicle speed to the ECM interface. what I don't get is that the turbo sunbird uses the same 7749 as the Sy/Ty & it is using the VSS inputs but the Sy/Ty is using the DRAC input. I checked out the print for the ECM (thanks again to Ludis), & it appears that the ECM might not care but not sure. that is to say that both signals are there & the firmware can read in what it wants. maybe this is one of those things that the memcal is going to "SET" when it powers up. Oops, now onto another subject (for another day).

So, in closing, assuming that the VSS thing is not an unmovable object, this sounds like a no brainer. move some pins & rip out some hardware (smog stuff, same disclaimer applies. I know more weasel words) & this ought to be "simple". I have an excel spread sheet of the sunbird to Sy/Ty to "Camaro" pinots & names. I was going to add circuit numbers but got rather tired last night.

if anyone has any input on the VSS stuff please help to enlighten me. there is a huge vacuum in my head that only a true California blond could appreciate, fill it up.


Bob Wooten
r71chevy@earthlink.net
www.r71camaro.homestead.com

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Bob Wooten
71 Camaro, 91 EFI, 01 HP
r71chevy@earthlink.net
www.r71camaro.homestead.com

 

Bob, boy you have really dove in..hehe. I ahve been following your thread here and on the mailing list and WOW..really some great info popping up. I am at present rewiring the dash. I had installed the entire harness from the bird into my malibu and cut down the bird dash to fit in the malibu. I have now installed a Monte SS dash and gauges and gutted the bird harness and installing a Monte harness, then add the TPI to the Monte harness. Not something I was planning on. Also I have to "adjust" the EFI harness from a 7730 config to the 7749 config. This VSS question is timed perfect. I lost the electric speedo (T/A) with the dash swap and now I need a VSS with a cable fitting. Do you know if the 749 needs a 2K PPM or 4K PPM (Pulses per mile)? Great job, Bob Ward

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79 Chevy Malibu Cpe
305 TPI/700-R4,3:50 Posi 9 inch,
Custom Turbocharged,
ported upper and lower intake,
214,224 duration .450I .465E lift
749ECM, modified SyTy software
Website:
www.turbotpi.homestead.com/SATURN5.html

 

Bob,

did you mean the gmecm list? if so you will see that it does not matter (on the VSS thing). if the harness that you have now has the optical PU then it goes to C6 & if it has the magnetic PU then it goes to B10 (where mine is). then when you get start editing the Sy/Ty bin you set it for either optical or Magnetic & bang you are off & running. It just came to me that if you are going to use the magnetic you are going to have to set it to 4007 PPM & to 2000 something for optical (i bet 2003, but not sure) Also you are going to have to go in & set the injector size & # of injectors to 8 cyl anyway so..........

Hope that this about covers it, I still have the DIS project to work on, I hate getting side tracked like this, but i learn just SOOO much. I am hoping to hear back from Chet on his toy, & see what he is doing.

hows yours coming when you going to fire up that beast?

BW

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Bob Wooten
71 Camaro, 91 EFI, 01 HP
r71chevy@earthlink.net
www.r71camaro.homestead.com

 

Bob, have you made any progress with this?

 

I have not gone any further. I dont have any more questions. I think that it is doable & is not really any big deal. I have talked with a number of people that have done it & it is pretty much a no briner. the one gent that i talked with has a little four banger that he has his on. He is running a 1 bar map & can switch from the $8D to the $58 any time he wants. he does not have the turbo set up yet so he has not gone any further. it appears that stage one was to get the code running, stage two is installing the turbo & stage 3 is dialing it in.

I have not decided how i am going to go yet (blower or turbo, I think turbo) so i have not pursued the ecm any furher. w/the setup that i have I think that a single turbo @ 10 psig is going to be great & about as much as i am going to get out of it w/the cam & heads that i have, so this would be a perfect fit for me.

right now i am looking into what it is going to take to get a turbo into my car. I am thinking of using a turbo Technology pass side header & doing a single. He said that he has had customers doing 600 hp singles with that header & this is about what i am shooting for with this motor.

Saturn5 is supposed to be firing up his beast sometime this spring/summer & i am really looking forward to hearing how it goes for him, although I think that he has decided to put the 7749 ecm into his, w/the Sy/Ty code in it.

Hope that answered your question, I was not sure where you were headed with it.

BW


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Bob Wooten
71 Camaro, 91 EFI
r71chevy@earthlink.net
www.r71camaro.homestead.com

 

PS, when i get the turbo Tech header I am goign to stick it into a buddies 3rd gen (see my sig line, i am 2nd gen) & see if/how well it fits. if so maybe a group purchase is in order.

we will see when we get there.

BW

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Bob Wooten
71 Camaro, 91 EFI
r71chevy@earthlink.net
www.r71camaro.homestead.com