Is it really as simple as repining the wiring harness to match the pinout of the 749, plugging in the 730 and burning a proper chip? I know that Saturn5 has run both ECM’s with the $58 code but I don’t know if there was any repining involved.

Has anybody sat down and figured out the pinout to do this in a car that originally came with a 165? Anything to look out for? Anyone have a pinout drawn out for the conversion?

I was seriously considering cutting apart a fried 165 that I have sitting around to get the ecm side connector out of it and then soldering up an adaptor harness, but after looking at the thing I have a hard time believing that that would be all that reliable unless I took the time to make a little PCB to solder the jumpers to…, so at this point I’m probably just going to swap pins to new connectors and add a MAP harness/plug (probably right to the original MAF wiring)

 

One of several I've done.

http://home.woh.rr.com/brucesgn/749togn/

 

Huh, any problems with putting strain right on the connections to that socket? That’s mostly what I was worried about with that. Your assembly doesn’t really have any provisions for releaving that strain and would actually be pretty difficult to wrap/cover up/protect the connections for a long term/permanent installation, but it looks EXACTLY like what I intended to end up with.

Anyone have any info on using the 730 as a 749 or about repining the 165 harness?

 

Here is a 165 to 730 pinout

http://www.speedtoys.com/~bort62/7749/86to92.txt

Here is a page on the 730 to 749

http://www.speedtoys.com/~bort62/7749/Main.htm

I am 99% done wiring in a 7730 as a 7749 to run $58 code on my turbo DIS 3.4 DOHC in my Fiero.. A couple of wires away from trying to start it.. Should be interesting to see if it actually runs..

Cheers,

 

~40 solder joints, and 40 pieces of heat shrink.

 

My harness started as a MAF harness, to which I changed to match a Typhoon harness with the 730, and the 749 with sat injectors, and also as used in a Sunbird with a driver upgraded 749 with SVO brown tops.

That harness is now pulled from the malibu and waiting for me to adapt to the SVO now that the core support swap is done.

I finished changing/replacing the front inner sheetmetal forward of the strut towers. Also went with a 87 up section as the late model came with a fiberglass bumper over the original steel 84. Not the simplest way to replace a damaged core support but....

 

that's how I have mine (like grumpy's ) I used a 730 ecm on my 88 maf harness the same way but, I hot glued the hell out of it once I made sure it ran and the wiring was good. (I overkilled it with hot glue) seems to work good

 

I'd just repin the 165 to 749 specs. Took me like 30 minutes, and i've been back and forth between 730/749 a few times too, trying real-life differences between $8d and $58/$60 fueling.

A lot of us have done this with some really good results. Good luck with yours!

-- Joe

 

Yea, it really looks like repining is easiest, I’m actually just dreading sitting down with the pinouts and figuring out what goes where.

With the text file linked to either the above site or Mike’s site… am I seeing right that the last column is showing the 749 equivalent?

 

It's not nearly as overwhelming as it seems..

Yes, if you use the pin locations of the last column, you will be able to run the $58 code in your 730. The 730 only requires minimal changes to run the 749 code.

Cheers,

 

Well, since I’ve got some issues with the 165 that I haven’t been able to trace down I’m finally getting around to doing this…

Looking at the pin to pin chart on Mike Davis’s site I’m guessing that the pins starting with “B” are in the 2 black harnesses and the ones starting with a “G” are the ones from the yellow plugs?

What do I need to do with the KS setup? Can I just unplug the ESC and jumper the pins or something?

 

You can jumper the pins at the ESC and you also need to put a resistor on the KS signal if you are using the "165" KS. Go to my home page for pictures of my harness/installation......

/N

 

I’m going to go look at your page now.

Looking at the speedtoys site, it lists Mike Davis’s pinout changes that lists the 165-730-749 pinout changes , and then separately it lists a list of 730-749 changes and they do not match.

What are you guys doing in these cases (listed as 730 -> 749 canges):
- speedtoys lists C1 -> B12 (VSS for cruise) that is not listed on MD’s site
- ST reverses the injector driver outputs, MD doesn’t (not sure if it matters for batch fire)
- ST wants you to disconnect F2 (air pump solenoid), nothing about it in MD’s list.

 

Well, I did the repining… will mess with the MAF and ECM’s tomorrow, but I ran into an additional conflict.

It looks like MAF pin A is D1 on the 165, but the chart shows D1 as a chassis ground and has you move it to the new chassis ground on pin BD1. Where the recommendations for repining the MAF harness to a map harness suggest using Pin A as a MAP ground that should go to BB6.

Does it matter? Is there a difference between a MAP ground and a chassis ground?

 

The way it works is kinda dumb in my opinion. Instead of having a huge ground to the ECM, it needs several grounds for components. Basicly MAP ground is the ground that goes from that pin to the chassis to provide ground for the MAP driver.

-- Joe

 

I’m not sure if that answers the question… well, it might but it doesn’t alleviate my confusion… so can I use that pin as a map ground, or is that a pin that should be connected to a chassis ground?

 

I saw the picture, looks like you have the 2 pins jumpered and then a resistor connected to another pin? Do you mind sharing details (how you have it wired and resistor value? Looks like a lot of the information on MD’s site has broken links now and the searches done here seem to say “inline” about ½ the time and from the signal to a ground (Voltage splitter?) ½ the time, and some are saying 3.9 and others 4.3 ohms (I suspect that the actual resistance isn’t that big a deal, as long as it gets it to somewhere near the correct range)

FWIW, I was hoping to find the MAF plug somewhere with no luck (I know what it is, it’s a male, 150 series 5 position Metri-Pak, just can’t find one). I guess that I’ll just splice into that harness or cut the maf connection off when I decide where to mount the MAP (I don’t appear to have any open vacuum ports on the manifold, so that is a bit of a debate, right now it’s looking a lot like it’s going to be the FPR port even though I don’t like the idea of exposing the MAP directly to gas vapors from that port.)

 

The resitor is a 3.9kOhms and its connected to ground on the ESC plug (D), I put it there so It should be easy to remove along with the jumper If I would like to switch back to the 165ECM.

So just put the resistor to D on the ESC plug and then connect it to the jumper, the jumper should be between C-E....


/N.

 

Mark, You want to wire it as a Typhoon since the 730 just has the single injector driver. There are copies of the GM wiring on the diy ftp site or I have copies I can email you.

The only issue that may or may not is the IAC. Some are wired opposite of each other, so the IAC may close when it really wants to open. Just reverse the wires, and go at it again.

 

Is the IAC problem using a 730 vs a 749 in the same harness with the same chip? I know that you said that you’ve tried both before and I thought that you said that it worked fine with no other changes.

GTA324- thanks, that makes it clear, basically you’re building a voltage divider…

Looks like the broken links on MD’s site are up and running again…