Problem with 1981 Eldorado ECM and PROMS

[www.eldorado-seville.com]

Hi.
I´m helping a friend of mine restoring his 1981 Eldorado.
We are having an electronic issue with the ECM at the moment and are looking for the first design EPROMS in the ECM.
The Eproms we are looking for have the numbers 7977FT and 7978FT. We have found second design ECMs and EPROMS but the car does not work with them at all, thats why we do need exactly the correct ones.

Does anybody have a first design ECM (#1224760) including EPROMS (7977FT and 7978FT) laying around somewhere or knows a source where to get them?

We are very desperate at the moment as we are trying to find them for almost 6 months now... The whole issue with the ECMs is going on for at least 2 years now.

The car shows the following symptoms:
The "Service Engine Soon" light is always on. The car is running in "emergency mode". The display of the onboard diagnostic system turns blank after 1 second after it displays "0" when the ignition is turned on . Diagnostic mode does not work at all. We went through the whole trouble tree in the shop manual and made all the tests and its coming down to either the ECM or the Proms. We also checked all the wires and everything else. As the ECM is a new rebuilt one it must be the PROMS. The car does not work with second generation ECMs and Proms which are easier to find.
We had the car at 4 different Cadillac dealers and 2 electronic engineers to have it checked with no success so far. We went through 4 ECMs before we found out that the EGR valve caused the ECM to burn through (something all the professionals did not find out). After that it worked fine for about 3 months before problems started once again... Its extremely frustrating and we do not know what else could be done and where to get the correct Proms for this car as they are no longer available anywhere.

thanks,
Gerald

[TJ Hopland]

I assume this is an 8-6-4 ?  And thats why the prom is different than other models, not to mention later more common ones were a much smaller displacement motor?

[www.eldorado-seville.com]

yes its the 368 8-6-4 engine

[Warren Rauch]

   In Serviceman Bull# 81-17 , They cover some of the problems you mention. In the first generation , there was no code for a poorly seated prom . In gen 2 it was code 51.  This may be all your problem is.Try reseating it.
  You mention doing all the tests in the shop manual. Section 8-D  was replaced during the year by the " 1981 DFI and CCC Diagnosis  Manual"  ( this from DSTB 82-I-7) Warren

[www.eldorado-seville.com]

Thank you Warren I will check it out.
Excuse my dumb question but what is DSTB82-I-7?

Thanks,
Gerald

[homeonprunehill]

GERALD, you mentioned that you or your friend has purchasted a rebuilt ECM that didn't  do the job. Why not go back to them ,yes  I know all about the signs all parts stores have posted "no return on electronics parts", "but I also know that the squeeking wheel gets the grease".HTH,Jim   Talk to the owner if you have too. just don't take no for an answer!

[Ohio57-62Sedan]

7977FT and 7978FT  are good number's nobody has any anywhere... I looked through about 50 ECM's here and I dont have one.. I called Cardone for you and they told me the number's are still good number's.. they don't have any in stock.. you can give them a call 1-888-280-8324 they may get some in the future.. But for now I'll keep looking for you.. Good luck...

[Warren Rauch]

 DSIB stands for Dealer Service Information Bulletin. They were another series of bulletins that were sent to the Dealers.
  There were also Dealer  Service Technical Bulletins,Dealer Emission Bulletins and Dealer Product Campaign Bulletins.The emissions ones are obvious. The campaign ones are recalls the dealer was ask to fix. But where the line between service info, technical and Serviceman was I don't know. In this time period Cadillac started to make bound editions of the Cadillac service bulletins of all kinds. ( the 81-83 were combined when printed in 1989 and only the ones that had not been superceded are included. I can photocopy the couple pages if you want.)Warren

[paul]

I got a 81 sedan deville parts car out back. That has that 368 motor . That was a good runner . I drove it out back. Dont know if its same as eldo on that part.