Good evening all,
I am looking for ECM number GM 1225550 or ECC5550 for my vette. so far I couldn't it anywhere.
I sent my ECM to rebuild but the lab said not possible. If I remember right 1984 auto vette has the same ECM? please share some info if you can.
If there is other way or upgraded ECM that I can install as plug n play that can be another option. currently the car is totally dead.

 

I thought all the ECM's were the same across GM cars. The PROM (chip) is different between cars which is a plug and play item. do you still have yours?

 

Yes, I didn't open it yet

 

I'm thinking you just need a ECM that GM used in 1982 in any GM car, take your PROM out of the old ECM and install in the new or rebuilt ECM. The PROM has the info on it for it to work. PROMS are car model specific.

 

What is the PROM is bad? how can I check it?

 

I could be wrong, But I do know you must keep the PROM from your old ECM and install it in the new one.

 

You can't check it. P.R.O.M. stands for Programmable Read Only Memory. It is a computer chip, they rarely go bad.

Autozone has what you need.

https://www.autozone.com/engine-mana...11133_609218_0

The PROM should look like this.

https://images.oreillyauto.com/parts...om_carrier.jpg

 

out of stock

 

I was looking or other GM 1225550 part number, but the plugs are different. won't work

 

Your right none of the parts places have it. It is now a discontinued item. That's a big problem. You might try Dino's Corvette salvage? Sorry I couldn't be more help. You might try posting this in the C4 sections, 1980 was the first year for ECM's, all the C4 guys have them. 1984 ecm might work, the engines in the 82's and 84's are the same.

 

You probably will NOT find any 82 ECMs anywhere, they are like hens teeth now a days. The 84 auto will work, but you probably won't find any of those either. Also, the other ECMs from other GM cars will NOT work for your 82, period. Even if you happen to find an ECM, it's a crap shoot if you get a good one. There is another way around all this if you want to go that route though. If you want to laptop tune your motor, buy a HAM board, buy and ECM from Dynamic EFI which is the EBL Flash II and I can give you a tune BIN file for a stock 82 that will get you about 98% done and very driveable. It will save you a ton of tuning and you can tweak the tune if you want. At least you will be able to drive your 82, as it sits, you are dead in the water without an ECM. Let me know and we can talk and I will give you my number. PM me.

 

Idan55,
Have you decided how to proceed?
A 1984 computer 1226026 with the PROM “CDR 3940” will work “plug and play” in your 82 with no modifications to the plugs or engine.
You will probably pay in the $250-$300 range if you get one on the bay. Often they are sold without the PROM so you would still have an issue to solve. If you see one listed, ask the seller if the PROM is included.

The 1226430 is for the 1984 manual transmission and will run in your 82 but with a high idle. I am sure this can be changed but would require a re-flash by a competent programming shop.

After a year of searching, I finally gave up on finding a complete 5550 ECU, so now I run a 6026. It works great.

They come available from time to time - you need to keep checking. After all, they built 50K of the 84’s. They are out there. There were two available at the same time a few months ago.

I will keep looking also.

 

Thank you! At this point I don't really care if 82 or 84 as long as I have the car running.
I belive 82 prom can be installed at 84 auto ecm, right ?

 

No, I don’t think the PROMS will cross over from 82-84. Different design.

If you do find a 1984 ECU, you can get a Hypertech chip for about a $100 to go in it. (I think it is 11401) Summit Racing sells them. I have no personal experience with the aftermarket chips, but that is something you could explore when you find a 6026 computer if no chip. One will pop up soon. Every few weeks one comes up.

Check Dino’s Corvette Salvage in Mississippi. You can be put on a waiting list and will notify you when one comes up. I was on one then I found one on the bay. Soon after, I got a notice Dino’s had one. Otherwise, keep checking the bay.

 

Let it be a warning for all '82 owners. If you pull the PROM chip out your ECM and accidentally reverse it when you try to reinstall the PROM back into your ECM there is a 100% chance that you will instantly fry your PROM and a 90% chance or greater that you also fried the board on your ECM. An expensive 'oh sh!^.
I did it a several years ago while installing the above-mentioned Hypertech Streetrunner PROM. My pure stupidity, and I highly recommend the superior Hypertech PROM chip over the stock, ultra CAFE friendly OE chip; but, be aware that the part #/script on the Hypertech chip was printed the reverse/upside down vs. the original chip and I made the mistake of ignoring the little proper orientation notch and used the orientation of the printing on the new Hypertech Streetrunner chip. An expensive mistake, requiring a new chip and ECM. (at least there were still plenty of remanufactured '82 ECMs available 5 yrs. ago). I suspect that Hypertech PROM label misprint has alone caused the ECM shortage due to a simple oversight by an unknowing chip assembler. And, customers like me not paying close enough attention to the proper PROM insertion orientation.

I wanted to share this to help others avoid mis-installing the PROM chip which is quite easy, but unforgiving if you as I did - somehow ignore the small PROM orientation notch. And, also to bestow first-hand praise on the noticeably improved drivability by installing the Hypertech Streetrunner PROM in the '82-84 EVM and with no noticeable downside except the suggestion to use higher octane gas - but, worth it to me for the improved RPM shift points (far less lugging), alone.

 

Thank you!
Can you share a like fir the new PROM?

 

https://www.summitracing.com/parts/hyp-11721

here you go. It is an affordable improvement for any ‘82. If you need to buy an ‘84 ECM be sure to get the ‘84 application which likely compensates it’s program logic to account for the ‘84’s faster processor/strategy but confirm this with the Hypertech folks whi were personable and responsive to my inquiries before I bought one. Again, it was well worth the cost if only for the upgraded transmission shift strategy, and engine responsiveness ;when using premium gas).

good luck - and, I just ask that you do the same for somebody else in our awesome hobby when yiu have the opportunity, sir

 

Like Buccaneer said, you will have a hard time finding a rebuilt ECM, and most of them have been through the mill; they are junk. I've been through this. The EBL with HAM board makes it a direct plug-in to the factory harness, and to the untrained eye also looks completely stock. You're also getting updated electronics, a faster processor, and support, aside form being able to watch live data on a laptop to troubleshoot sensors, timing, etc. I would highly recommend this for anyone that's in need of an ECM, and doesn't want to gut their whole induction setup. Well worth it, IMO. I would even go as far as to say with time and patience, you can have it running better than it ever has.
Oh, and I left out another juicy part; the flash holds at least 6 or 7 tunes that you can toggle between, so you have an "undo" capability if you get carried-away. ;-)

 

I got today the 84' rebuild ECM. I am looking for 84' PROM . it also can be performance PROM

 

Here's someone giving away a bunch of crossfire parts, including an ECM:

​​​​​​https://albuquerque.craigslist.org/p...236858511.html