Was at a junkyard saturday looking for one. Out of about 20 I saw in cars, every one was remanufactured. Not one original! What's the story?


Mike

 

My car came from GM with a remanufactured ECM. I did not understand it either.

 

Lots of ecm's get redesigned after a few years to fix shortcomings. If you go over to diy-efi.org you will find ecm listings and it should have numbers for the updated ones. Obviously the updated ones are the ones to have but you may find that the original numbers (730, 727) will work just fine. Just make sure to get the GM reman ones. I don't trust the aftermarket ones but that's just my opinion.

 

When I worked at a dealership back in the early 90's, I personally replaced a BUNCH of the 730 ECM's. Many of those were in "A" and "L" body cars, but it did vary. I used to think it was due to the 730 being a pile of junk, but now as I've been researching this stuff for when I get started on PROM burning, and EFI on my Camaro, I realize how many of them there are out on the road! It seems that nearly every 2.8 and 3.1 FWD car used the 730 for several years! I know heat killed a few of the ones that I replaced, but the others, I have no idea what killed them! I have also learned that it seems to be one of the most sophisticated late 80's ECM's. I just can't wait to get hacking one in my car!

 

HE!,

I've two original 730s here, running in South America: My Celebrity'88 and my wife's Corsica '89. When I reprogrammed the PROM I saw the following label in the 730's Celebrity:"This car has been updated with the 87 - 88 Speed Density software. See technical manual....". What's this story?

Denis.

 

Working at a dealer you do see the problem cars.
And remember the 730s were used more then just about all the other ecms put together. So you would see alot of them.

The 730/749s are a great little ecm.

 

At first GM thought they were going to have to use the MAF system to meet emissions, later it was found out they could with the MAP system. MAF sensors cost alot more then the MAFs, so they figured on recalling and updating everyone to MAPs, to save on warranty costs. Least that's the story I got.

 

It was kinda nice that they had both MAP and MAF on the car, so that all it took was a PROM change to switch back and forth! It was a TSB that GM issued for anytime a MAF needed changed, and yes it was a cost issue. I'll try to remember to look up that TSB tomorrow to see if there are more details. I also have to agree that the 730/727 is a good ECM, but it had a bad rap with me from my experience in a dealership. I've learned better now!

I know I'll probably get some greif for this comment, but I was thinking about using a 730 on my 350 and wiring it up to use either MAF or MAP and developing a bin for each. Maybe even have it use the MAF under certain conditions and the MAP for others? I know it will take some serious source code hacking though. I guess I had better get EFI on the car before making big plans like that!

 

Pffft!, very easy:

I'm developping a diagnostic scanning sofware for my vehicles (the "A57" GM datastream = some GM V6s 1987-1990). I'm hacking the bin with MAF & MAP: it's the $6d mask. Since my car run with both sensors, it can run with the $88 bin too. For this reason this car was a beta-tester for the new $88 code from Tuner Cat (for my contribution they gave me a gift: the free registration at Tuner Cat tuning sofware).

My next project is: When I need use the MAF v/s the MAP? (When I need tuning the VE curves v/s the MAF tables?). It's more "fuel efficient" using both v/s only one?


Denis V.