Is there a way to tell if the ECM was for an automatic or manual car? There is a member on this board who has a Camaro ECM with the service code of 1227165. He doesn't know if it came from an auto or manual car.

The previous owner of my car did an engine swap (put in a 5.7L TBI engine in the place of the stock 5.0L TPI engine). BUT he didn't bother switching the ECM's. I know it's not good for my engine, but I am doing an LS1/T-56 swap in the near future. The lowest quote I could get for my ECM was 400, and that was if I knew everything about the car (which I don't, since the previous owner did a LOT of mods). So I wasn't gonna bother replacing it.

The only problem I run into is, I can't give it more than 1/2 throttle, or the check engine light comes on and I lose pretty much all torque. I'm pretty sure it has to do with the fuel/air intake, because the car is confused. Also, the shift points are incorrect (the dummy light). Which I don't use anyways, but that's another effect.

So I'm just wondering if I would be able to tell, or if it matters whether it was for an auto/manual car. I did a search, but didn't find much out. Maybe I was searching the wrong thing, who knows. But some help would be appricated!!

Also, what would be a fair price for the ECM? I'm supposed to make an offer, and have NO CLUE what one is worth. Also, will I need a different wiring harness or anything like that to switch the two?

THANKS!!

 

The only difference between an auto ECM and a stick ECM is the calibration. For the '165 & '730 (in your '91) the calibration is contained within the MEMCAL (see sticky above).

Using an auto cal in a stick car isn't too bad. the opposite, a stick cal in an auto car is bad. The TCC will not lock/unlock at the proper times.

To tell which cal is in an ECM, pop the small cover off (2 screws) and get the 4 letter BCC off of the PROM. It will be something like APYP, or AXCN, or AUJP, or something else. Post back with that and folks here will post back what you have.

As for an ECM, anywhere from $20US to $50US. The '730 ECM came in a bunch of lessor cars. So it isn't always required to get one from an f-body (they always ask more for those. . . ).

One problem you are going to have is that there is no factory calibration for a 5.7l and stick f-body. May have to roll-your-own.

RBob.

 

Hey thanks for the quick answer! Good to hear that it won't be too much of a problem!

And the 5.7L + stick has made it difficult for me to find an ECM. Which is why I had a bad feeling that this was going to come from an automatic car. And I believe that's also the reason the previous owner left the orginal ECM in as well. He actually lives in the same area as me, and the closest place I found that would burn a new PROM for me was in Phila, and the $400 was only if I could walk in and tell them everything about the car. And I don't know The previous owner didn't do any of his own work, so he wasn't even sure. Apperently he had a friend who was a mech and did all the work for him, and made the final decisions, which is another reason I would like to swap the engine/tranny. So I know more about the engine and what exactly went on!!

What all is involved in "rolling-my-own"? Is this a difficult process??

THANKS!!

 

It sounds like the engine is possibly modified from stock. If so then a PROM calibrated to the engine is required to give the best results.

Here is a TGO link for an introduction to burning PROMs:

https://www.thirdgen.org/newdesign/tech/promintro.shtml

The PROM in the MEMCAL contains the calibration information which needs to be changed. It isn't difficult, can be somewhat overwhelming at first, but once you catch on it becomes addictive.

Basically the bin (binary image from the PROM) is modified using an editor. Ths image is then burned into a PROM or flashed into a Flash chip.

Data logging through the ALDL port is used to gather information on how the engine is running. Using this information intellegent changes to the calibration can be made.

The DIY PROM board has a ton of information on re-calibrating the ECM/MEMCAL.

RBob.

 

Help please....I have a 91 rs with the TBI engine. My check engine light comes on every now and then and shutters a little while on. I ran code and got a 23. Book says MAT sensor or ECM. I've read on here that TBI cars don't have MAT sensors. Can someone tell me what I need to replace to stop my CEL from coming on.

 

My book shows a code 23 is MAT or IAT. You have an IAT in air cleaner.