i would like to know if the emc from a 91 LB9 trans am would work in an 86 camaro with an 87 LB9 motor. i just finished this new motor rebuild and the ecm from the trans am was a junk yard pull and looks to be in good shape. should i just swap out the memcal or the whole ecm, and if just swapping the memcal is good enough can i get the old one reprogrammed?

 

No. That's the '730 SD system. You can convert to make it work, but it's not a "plug n play". You would need to convert from MAF to a MAP system to use that computer. A lot of people do convert from MAF to SD for a variety of reasons. But I prefer to convert when your MAF bites the dust, as a new MAF makes the conversion cost effective.

Also, the proper ECM, which I mention below, was used in only a few GM vehicles and getting harder to find in a junk yard. The '730 SD was used in a LOT of cars, most noteably late 80s-early 90s V6 J-bodies. So it's easy to find, and cheaper (if you can find a '165).

For "plug n play", you need a 01227165 ECM, which is found in all TPI F-bodies & Vettes from 1986 to 1989. The eprom from the 1989 is a better "vintage" of calibrations and can be used on any pre-1989 (86-88) F-body TPI. All you have to do is disable the Cold Start Injector (9th Injector).

 

thanks for the reply, I just found out that this one would not work. i plugged it in and drove the car, and while it did run without shutting off, it drove horribly and i then thought about the fact that the vehical the chip came from was a speed density set up.

so i guess i need to get over to the other board and see about programming this thing. or maybe i will just buy a hot chip from summit.

 

Check around... if you dont plan on doing the programing yourself, you might have other and better resources for an aftermarket chip... save some bucks on a custom chip, shop around or ask one of the members here for advise before you catalog order a chip for your individual car.

 

I'm rather surprised. I sense there may be some confusion in terminologies. The 730 ECM (computer) has different connectors than the 165 ECM. You cannot even connect a 730 ECM to a 165 harness without modifications.

I think you may be talking about the "memcal" (which people often call the chip) which holds the eprom plus other circuitry. You plug the memcal into a socket on the motherboard in the ECM (computer).

It's possible that the memcal you had was for a MAF TPI (1986-89) car, but it was not setup properly for your car - thus it ran, but not very well.

A memcal for a later model (1990-91) SD TPI car will not start the engine if you plug the SD memcal into the stock 165 ECM found in MAF cars.

 

Just a clarification, the '89 systems has VATS, so you cannot use an '89 chip in an 86-88 car without VATS. It will not start. You will need a custom '89 chip with VATS removed. Also, the cold start injector only works when the temp is less than 40 degrees F. Simply unplugging the wire at the front of the intake manifold should work. Its a single wire on a large sensor. The other one is a two-wire smaller sensor; that is your water temp sensor for the ECM.

A good generic custom chip can be made by Ed Wright at http://www.fastchip.com/

 

yes, it was just the memcal that i put into the silver box's mother board. guess i will check into the custom chips. one more question, today while coming home from a 45 minute trip the check engine light came on. after i got home i checked for codes and none where there. has anyone come across this? also the car started to run a little rough while the check engine light was on then maybe about 3 mintues later the car was fine and the light went out and did not come back on again. strange, right.

 

Yes, it's a two second change to a switch in the eprom. I consider this a minor change similar to changing the injector size....not real tuning IMO. And definitely not worth anymore than a few bucks for someone to do it, if the person charges you anything at all to do it.

And depending on which version of the 89 memcal, there might be a few other things that need to be tweaked. Again, all minor.