Many proms were updated on the production line and at dealerships to correct problems. Snap-On had a book that listed the updates and the reason for it. I have 1 buried in one of my tool boxes and will try to remember to look for it and see what it says. I think you may have an ECM problem not the Prom but I could be wrong,

 

Witam,
There are a couple of owners with a lot of 1981 8-6-4 experience. Maybe they will see you post. The only topic I've read, getting remotely far into the ECM on these, was on the CLC Forum but a large percentage of the members are gone and there were no magic solutions revealed. I do recall though that owner found signs of over heating and I think it was determined it had something to do with the solenoids which are responsible for cylinder deactivation. I guess you would have seen signs of over heating though if you've already gotten into the ECM.

Scott

 

Hi Peter, I have three 81's with the V864 engine and have gathered lots of info on them to help me in future if they have any issues. I have read a number of posts over the past few years that have the same issue with only displaying "..". I have also read somewhere in the past that it is a serial communication issue with the ECM. I have attached a scan of two pages from the "1981 Cadillac Digital Fuel Injection and Computer Command Control Diagnosis Manual Supplement" that you may not have. Hopefully it will be of some help. I also have all the Electrical Drawings so if you do not have them I can scan appropriate pages for further information. I also know of another 81 Seville owner who happens to be in Polland and can contact him to see if he might of any help to you. As for the PROMs my suspicion is that your issue will be with the ECM and not the PROMs. I have never had to change ECM's in any of my cars but do have some original spares that I can open up, as Scott suggested you do to yours, to compare for burnt components. I will watch for your reply and hopefully we might be able to get your car running decently again. Dave

 

81 BENY Biarritz this is not about this post I couldn't find a different way to message u so I'd like to get info on my 864 I have a coupe deville it ran okay then had a major problem I'm hoping u can help point me in the right direction on how I should go about fixing it thank u for your time my email is Levcole59@yahoo.com if we can connect and see from there how we can discuss this problem thank u for your time

 

Hello,
Thank Y'all so much for contributing to my post. My hope grows with every word you write.

Replying to: dogbiscuit
You may be right, I said that maybe PROMs are bad, but this was based on only one article I've read and it needs further investigation.

Replying to: 1979 Eldorado
As far as I remember I disassembled ECM case about 5 month ago and everything looked fine, but it is worth checking again. Yesterday I took the computer out again and maybe today I'll be looking further into checking everything out one more time, but I'll do it more carefully.

Replying to: 81 BENY Biarritz
Thank You very much for providing me so much informations, I'm glad that You're helping me out. So as I said above - in free time I'll be checking ECM one more time to be sure how everything looks inside of it. Unfortunately I only have owners manual that I bought from USA and no any service manuals, so I'm very grateful that You're providing me these. You can contact owner of Seville in Poland and We'll see - it is better to have one more person that might help.


There is a one more thing that I've found when taking ECM out of car. Somebody in the past was interfering with wires going to one ECM connector. I was thinking that maybe it is causing some sort of problems, but since the car was running fine with this mess before I don't think so(maybe I'm wrong?). Of course in future I want everything to be as it rolled of assembly line, so sooner or later I'm going to fix this up. Maybe this wires are something important? I'll attach You some photos of its - maybe by a electrical scheme We can figure out where these wires go? As far as I tracked them down - two black wires that are connected to one unisloated wire, are going to distributor, and the two others (red and white) go somewhere up in the dashboard with a bunch of the others, near the center but closer to driver I think. I just can't understand how is it working? Originally two wires goes to the computer, but now only one of it. Did somebody wanted to bypass ECM?? If this is possibility, then why would somebody do this? I suppose that something stopped working and instead of fixing it the right way, he chosen the shitty way (pardon me).

So one more time - big thanks to everyone, now let's get going. If I'll be able to check the ECM visually today then tomorrow I'll be checking it mounted in car using scans provided by 81 BENY Biarritz.

If anyone out there knows something about this connector wires, how it is supposed to look like and for what are these wires I would be very grateful for informations. Maybe You, BENY have a scheme for this?

I'm attaching two photos below with these messed up wires. I'll keep You updated.

Have a great day,
- Peter

 

If there was a Cadillac "Electrical Trouble Shooting" Manual for 1981 Eldorado or Cadillacs, all series, it would be worth getting. My 1979 is totally different in the case of the ECU vs ECM but if you find the 1981 version it should have simple wiring diagrams with colors and wire size and even identifying, by number, each junction and connector. That's really an ideal manual to have for sorting out where the wires you pictured should be going. Thankfully Beny is really tuned into the information on the 1981. He will almost certainly know if the trouble shooting manual exists and what the cover looks like. For 1979 it was close to A3 size (11 x17inch) color manual with explanations of each circuit, tips as to how to test, and color diagrams with a table on each section showing the location, and even an image many times, of the junctions. They are incredibly helpful manuals.

 

Hello again,

Replying to: 1979 Eldorado
You're right, that manual would've help me a lot. It'll be very good to have it.

I was doing a little search for that kind of manual and I've found a used one for all 1981 Cadillac models for only 20$! I think that's very good price, but only shipping without taxes would cost me 40$ and take almost a month! Fortunately, a friend of mine have somebody in Pennsylvania, and he is sending some packages from time to time, but I don't know when he'll be sending the next one - it can be in a one week or in two months. It is cheaper to put this manual in one bigger package rather than paying 40$ just for this one item.

Question to: 81 BENY Biarritz
Since You've got fantastic experience and knowledge about 1981 Cadillacs, I have a question for You - is that one manual I've found would be good and worth buying or should I look for another one? I'll attach photo below because link is very long.

If this manual will be the right one, then I'll tell my friend to buy it for me, but as I said above - It may take some time before I'll get it in Poland.

- Peter

 

That's the manual I was thinking about. I've never seen the 1981 version but if it's anything like the 1979 version (best) or the 1983 version I have for Oldsmobile (very good but ~A4 format and no color diagrams) it will be well worth the price. If your friend can help look-up pages for you and send you a scan, the app "Lens" formally known as Office Lens, is great for scanning. BTW: My friend Rafal from Poland showed me that app originally (site doesn't seem to support special characters unfortunately).

 

Hello again, I was going to say that on one of my cars (the Seville by coincidence) that someone in the past cut into the wire #487 in the red connector for the third gear switch to install a switch to bypass the V864 mode, however this is obviously not the case with your car, you have some bigger issues to sort out. Attached are scans of the two pages from the same manual that shows the circuits that connect to the ECM.
As Scott mentioned there are very good Cadillac factory manuals available for troubleshooting both electrical and mechanical issues with your car and they are still very readily available from E-bay sellers at various prices. If you intend to do much work on your car they are an invaluable tool to have. I have also seen some sellers offering all the 81 manuals together as a group for what I would consider to be a reasonable price however shipping is always another additional cost to factor in. If you would like my suggestions on which are the most useful let me know and I can scan the front cover of each. Best to shop around though in any case as many are offered at unreasonable prices and there are always new sellers coming up all the time.
I am happy to keep scanning pages for you if that is what is required in the immediate time frame to help out. The only issue is that many pages relate to others and that may become frustrating for you to wait for me to send as you find new questions.
One thing that I did read on another page in the manual that I have been referencing is that "88" is the first character string that is sent from the ECM to the Climate Control head. It goes as a serial data string of between 2 and 4 volts that can be measured on the appropriate wire on the ECM. I have also read on some previous Forum posts that one issue that used to be common with ECM's problems in these cars is that they drive or get signals from many unfused circuits and that the ECM is not well protected from wiring shorts or solenoid failures. They warn that circuits should be checked before repeatedly replacing ECMs to determine if it is an outside issue causing it to fail.
Hope that the scans help and feel free to keep the questions coming.

Dave

 

Hi Peter, I guess that I was typing while you were posting about the manual. Yes this is a good one to have as it explains where on the car all the electrical equipment is located and typically how it is all connected. It is also is colour coded so that it shows all wiring as you will find it on the car. There is also an identical silver covered manual that covers just the Seville/Eldorado model and is a little thinner as this manual that you have pictured covers all models (with the Brougham/Fleetwood being in a separate section).
The manual that I am using is a black covered one and you should be able to find it easily on E-bay also. It focuses on the ECM system and all the troubleshooting of codes etc that are available in the diagnostics modes.
I had a closer look at the wiring diagram and I now strongly suspect that the wiring connections you have shown in your first pictures are actually factory original and should be left as is. Looks like they run the twisted pairs from the injectors to the ECM and the wires that are spliced separately would go the the injector fuses in the fuse panel located under the dash near the parking brake. So that is some good news for you...
Dave

 

Thank you Dave for mentioning me and for your private email, I will reply soon

Piotrze, mam co prawda 1980 Seville z 368 silnikiem, czyli bez funkcji odłączania cylindrów, 1980 a 1981 ma między sobą trochę różnic, lecz silnik i osprzęt został mniej więcej ten sam. Mam oryginalne instrukcje napraw, mam też dużo doświadczenia z tym silnikiem. Mogę pomóc, jak chcesz to napisz na niki23.122@gmail.com

 

Witam,
Dziękuję serdecznie za chęć pomocy. Jak na razie postaram się skupić na problemach elektronicznych i sprawieniu, by odpalał i normalnie chodził. W przyszłości na 100% będę chciał odświeżyć silnik i nie tylko, także Twa pomoc w kwestii mechanicznych rad i innych detali oraz dodatkowe informacje będą jak najbardziej mile widziane - odezwę się na maila.

Pozdrawiam i życzę spokojnej nocy,
- Piotr

 

Hello one more time,
I've got some updates for You. Because of some free time I managed to do something, so here it is:
First, I've checked ECM using 'DFI CHART #1' from Dave. Both fuses are OK, then I checked circuits #439 and #480 and they are both OK too. I also checked power going to the fuses and it is around 12V. Some days ago I reseated PROMS and there wasn't any change, so I think that it is not the problem in this case, but maybe I'll try one more time tomorrow, because today is too late for working anymore (almost 10:00PM in my timezone). I was also checking ECM connectors and they are looking fine too. According to this chart the ECM or PROMs may be faulty.

The next thing I've done was carefully disassembling ECM and checking it visually. I think that everything looks OK, but there are some strange, small uneven, raised parts everywhere on it but it's all solid and hard to touch. There are two resistors(?) that look different than any others, they're like bulged or something. Maybe some of You would know if it can cause some sort of problems and is it supposed to look like this or not. I'll attach some ECM photos below from outside and inside. If You have next ideas what to check and what to do I'm waiting for Your answers. See You tomorrow.

Big thanks for helping me out,
- Peter

 

Hello one more time,
I've got some updates for You. Because of some free time I managed to do something, so here it is:
First, I've checked ECM using 'DFI CHART #1' from Dave. Both fuses are OK, then I checked circuits #439 and #480 and they are both OK too. I also checked power going to the fuses and it is around 12V. Some days ago I reseated PROMS and there wasn't any change, so I think that it is not the problem in this case, but maybe I'll try one more time tomorrow, because today is too late for working anymore (almost 10:00PM in my timezone). I was also checking ECM connectors and they are looking fine too. According to this chart the ECM or PROMs may be faulty.

The next thing I've done was carefully disassembling ECM and checking it visually. I think that everything looks OK, but there are some strange, small uneven, raised parts everywhere on it but it's all solid and hard to touch. There are two resistors(?) that look different than any others, they're like bulged or something. Maybe some of You would know if it can cause some sort of problems and is it supposed to look like this or not. I'll attach some ECM photos below from outside and inside. If You have next ideas what to check and what to do I'm waiting for Your answers. See You tomorrow.

Big thanks for helping me out,
- Peter

I am 100% sure, that your problem is with ECM. I had similar problem. Simply, if you checked connection "serial data" from ECM to ECC panel, then two dots on ECC panel prove it's 100% ECM fault. Those ECMs are somehow weird, that any internal fault will cause no diagnostic system available. Resetting PROMs probably give you zero chance for improvement.
Those raised parts is simply solid, please remember it's 44 year old car and it have very simple electronics in it. It always looks like that, even in my new ECM.
You can try replacing those resistors, they can be possible source of your problem. It is definitely broken.

Witam,
Dziękuję serdecznie za chęć pomocy. Jak na razie postaram się skupić na problemach elektronicznych i sprawieniu, by odpalał i normalnie chodził. W przyszłości na 100% będę chciał odświeżyć silnik i nie tylko, także Twa pomoc w kwestii mechanicznych rad i innych detali oraz dodatkowe informacje będą jak najbardziej mile widziane - odezwę się na maila.

Pozdrawiam i życzę spokojnej nocy,
- Piotr

Nie wiem czy pisać po polsku, czy po angielsku W przypadku elektroniki też jestem w stanie pomóc, bo muszę przyznać, że prawie rok walczyłem ze swoim i przechodziłem przez prawie każdy możliwy problem z tym układem zasilania. Mam też stary ECM, który jest niesprawny, nie powinien za wiele się różnić, więc jakbyś potrzebował pomocy, to śmiało daj znać. Niestety na rockauto nie ma dostępnego twojego komputera, jest inny o innych numerach, niecałe 400 zł więc może warto zaryzykować, jeśli wymiana rezystorów nie pomoże.

 

As JGNZM wrote those bumps are normal. They are "pins" going through the board and then it's soldered on the back. I have seen some joints like that where thermal cycling causes a extremely tiny crack. You could inspect them to see if you see anything like that. Sometimes when a crack occurs it will work at one temperature but not at another.

Those misshaped pieces look like they are the shape of a resistor but I wonder if there's any chance they are not. Can you read any of the markings on them? The obvious resistors are the components which are about the same size but with colored bands/rings. When you first wrote "bulged" I immediately thought you were going to show an image of a bad capacitor because they often bulge when they're bad. Whatever those are they look like they were over heated because I cannot image they were that shape originally. I just haven't seen a large enough variety of electronic components of that age to know for certain what they are. Markings should tell us though.

 

Hello,
I'm very happy to see You posting. After reading all Your messages I think that I've got plans for today!

What I'm gonna do first is check the "serial data" wire going to ECC panel to be sure it is OK, and since it is shown in wiring diagram from Dave it will be easy to do, but I must remind myself how to disassembly center trim around M.P.G. display, because after over half a year I already forgot. Next thing would be checking these resistors in the ECM for any markings. Maybe JGNZM can help me out by looking into his computer if these resistors will be more readable than mine. As for cracks mentioned by 1979 Eldorado I didn't see any inside of the ECM, but since I'll be looking for resistors markings I'll take a look one more time. It is better to check all the things twice.

Replying to: JGNZM
I think that it will be better to write in English since everyone else can easily understand everything . According to my knowledge the ECM in my car with numbers '1225120' is the second generation one with more advanced diagnostic ect. The one one RockAuto is first gen one, and as far as I know these computers are often sold without PROMs and they are not interchangeable between these two. I think that practically You can change ECM to different one, but it must have its own PROMs dedicated to ECM number. Also as I remember correctly when Cadillac was changing first generation ECMs to the second generation they were also changing TBI and EGR. I think that I was reading about it some time ago, probably on this forum. As I said above - maybe in your free time You can take a look for these resistors in Your old ECM and see if there are any visible markings on them? I think that they could be the same, otherwise I'll be looking for a new ECM. I'll be very grateful for any informations.

So now in a moment I'm going to check last one wire and then I'll be checking ECM resistors. I'll keep you updated Guys.

- Peter

 

Hello Peter, you have a great deal of correct knowledge about the ECM and the changes that were made during the 1981 model year to try and make it better, I am quite impressed! Two of my cars have the later version ECM(1225120) and one has the original version (1224760) and so I now have spares for both. Also the PROM chips are different from the E/K body to the C/D body cars. They are identified by two letters with KJ being one of the later versions used on the E/K cars. The Cadillac Serviceman update book (gold cover) that was published for 1981-1983 bulletins has fairly detailed descriptions on what was update during the model year.
I took apart (partially) a spare ECM to try and get a picture of the "resistors" but the way they look on mine they do not appear to me to be like normal resistors with colour code stripping. I have attached some pictures. It seems like they have a wavy surface although they are not bloated looking like yours appear to be.
As for you not getting "88" there might be one other thing to try. I am wondering if the data request signal from the Climate Control head might not be getting to the ECM. If you look carefully at the wiring diagram you will see that the wire that is used also connects to the Assembly Line Diagnostic Link (ALDL) connector which is located up under the dash near the brake pedal (if I remember correctly). On later GM cars it would be the OBD1 port but on our cars it can be used to signal the ECM to go into diagnostic mode by grounding the correct pin momentarily. Be careful though to make sure you are on the correct pin as I think that the connector is shown upside down on the drawing versus how you will find it on the car. It is a long shot but might be worth a try.
I will try and send you a scan of the pages that discuss the basic test for the data signal a little later today when I have more time.
Let us know what your testing reveals.
Dave

 

One more picture that shows the "wavy" surface a bit better. On a second look at yours I am thinking that they don't seem to be all that different??

 

Hello Dave,
Thank You so much for the photos - You've got an excellent sense of timing, because I've just finished checking the wires that I mentioned a couple of hours ago and turned out that they're OK. I was going to disassembly ECM one more time. Since I've just read Your message and saw all the photos I think that these 'resistors' things looks exactly the same as the ones in mine ECM, so I think that maybe they're supposed to look like this. For now I won't be disassembling computer again and I'll just wait patiently for Your scans, because it is better to check everything related to ECM rather than just buying various parts and hoping that car will be running again. Everything is worth checking and any ideas are much appreciated.

One more thing about wires - As You've said about the data request wire going to the ALDL - If I'm thinking correctly You mean a diagnostic request wire, so it's Black/White and goes from ECM to ECC, and then as You've said to the ALDL. I only tested the one going to ECC, but You're right that the other 'half' also needs some inspection. Since today is the Saturday and I'm having some free time, I'm right now going to check this one wire to be sure it is OK.

- Peter​

 

The best would be to have a full electrical schematic of the ECM. It would take a lot of time but the good thing about those old circuit boards is you can generally see all of the paths. The thin metal on the board is like a wire and the pins serve to connect the components. Even though we don't know exactly what those "resistor looking" things are, if we knew what part of the circuit they were in, then you would likely know immediately what type of function would be suspect if indeed they are bad. Probably someone like Bruce Roe would know what they are by image. He doesn't work on these ECMs at all but someone like y=him would know. I know there are a lot of talented, and dedicated, electronics shops for cars in Poland and there are also very capable Universities. I guess one of the shops could identify the component and the University could possibly create a student project to map the ECM... or maybe a professor needs a hobby project.

Can you follow enough of the circuit that those over cooked parowka are included in to see what external wire they are connected to? After seeing the photos from Dave maybe that's normal but the ones Piotr posted to start with, to me, looked even a little more distorted. If they were diodes they should have a single stripe indicating direction. I was searching electronic "wire through" component images last night and I also came across one of a wire though capacitor and even a voltage regulator but nothing looked to be the same shape. I doubt anyone wants to do it but if one was de-soldered and removed it could be tested easily for resistance. Testing while still assembled has the risk of taking an alternative path, but that said, maybe the circuit is open on one side so you may actually be able to test it without removing it. If it's a diode, in one direction, the resistance will be close to infinite as those are like a check valve and the multi-meters are directional (there's also a diode check on most modern multi-meters).

Edit: I guess you probably know the old Polish saying "Ateisci nie wierza w Boga, ale kierowcy starych Cadillacow musza wierzyc" That applies around the world

 

Hello again,
It's been a while, but I tested part of the wire that goes to ALDL and turns out that it's OK too. I'm very happy since with every step we're getting closer to the solution of my problem.

Replying to 1979 Eldorado:
You're right that with a proper electrical scheme for ECM it would be possible to check everything and find a eventual problems, but I probably won't go that deep into ECM, at least for now. If every other chart and diagnosis would point to a bad ECM, at this point I think I'll just buy a remanufactured one. I know that maybe I could find a good electric shop, but from my experience I just don't trust everybody. I prefer to work on this car as long as it is possible for me. My friend bought '07 F-150 Harley-Davidson about eight months ago, there was trouble with too high fuel pressure or something like that - there was a lot of black smoke coming from the exhaust. It turned out that the engine computer was bad (but not only, the main problem was some power steering sensor) - he knew a guy that was very experienced and talented... but this time he failed... In the inside of the computer there was a small resistors (if I remember correctly?) laying around that later was all collected into a sealed box. He said that he have all the schemes etc. When he completed "regeneration" the car wasn't even starting. He used 103 resistor instead of 101 so instead 100Ω the resistance would be 10000Ω! Then he said that he doesn't have any schemes and he saw it somewhere on the internet and he thought that it is a good one... But that's just one example, and I'm not saying that everyone is like that. For now let's check all the wirings, and if it point out to a problem with ECM itself, we'll be talking about a possibilities. Also I must admit, that I've never heard this Polish saying, but I really like it and from experience I couldn't agree with it more .

So that's it for today Guys, unfortunately tomorrow I won't be at home, so probably there isn't gonna be any progress made, but when Dave will send some scans I'll get back to work. Thank You very much for today, I'm glad that I've found so friendly and helpful community of Cadillac Owners.

- Peter​

 

HI Peter, here are the scans that describe Troubleshooting the ".." display and a description of the checking the serial data output. Hope they are of some help. Sorry for some pages being upside down it is the only way I can put the manual on the scanner to hold the page open. Dave

 

Hi Dave,
I must admit that all of Your photos and scans are helping me a lot, it doesn't matter if some of them are upside down, no need to be sorry, I'm very grateful that You're helping me out . I think that in the next week I'll be able to check next things according to latest charts that You've send me. Because of my work in the next week the progress may be slower, but It'll be going on, slow but still going. Thank You one more time, and have a nice weekend.

- Peter​

 

"Also I must admit, that I've never heard this Polish saying..." No worries. The first part was from Duolingo and I made up the second part because, your topic, and this ECM caused a light bulb to come on... It was finally obvious why Duolingo wants me to learn this phrase. Whether it be for a Cadillac or another car, which isn't supported well by the aftermarket, we've all experienced similar situations where it seems only God can help.

I just hope you are able to figure it out. Your comments and Dave's comments about new and old versions of ECMs and possibly coming without a PROM make me think figuring out what's going on with your original would be a good thing. It would also be interesting to know what those strangley shaped components are and what circuit they're in. I was thinking, even if the entire ECM was not mapped, tracing that circuit to a wire might be interesting.

 

Those resistor looking things are likely just low resistance wirewound resistors. They look fine to me. Sometimes, in the olden days, resistors looked like this, they wound the chromium wire onto a spool and then just coated them in epoxy, they could end up looking "irregular".

Since we can still see that there is writing on them I think they are fine. You can check them with an ohm meter if you like. When they overheat the first thing that happens is the writing burns off or changes colour. These two in your pics do not look like they have been hot.

They are attached to the rightmost pins of two transistors, my guess is they are for current sense on the fuel injectors. Here's how the circuit works:

The injectors are supplied with 12V and then a wire runs back to the ECM and goes to the collector of a transistor. When the ECM wants the injector on it supplies a small base current which turns the transistor on and the current flows from the collector the the emitter then through the resistor to ground.

With the key on but the engine not started do you have 12V on both pins of the two fuel injectors while the injectors are connected to the wiring? Use a pin to pierce the insulation of the wire to test without removing the plug from the injector.

 

Hi Peter, had a quick look on E-bay for manuals that you might consider purchasing. Along with the one that you already found this would make a complete set of the best manuals to have. The black book is the one that I have been sending you the scans from and the silver book gives both mechanical and electrical testing and repair procedures for all the main components and systems. Price for this set is also quite good given it's apparent good condition. Dave

Pardon Our Interruption...

 

Hello Everyone,
I've got some updates for You. Yesterday evening I've managed to check a few circuits using charts sent by Dave. According to them, there is a problem with either ECM or PROMs. JayArr was saying about checking injectors - I didn't check the voltage on the injectors pins yet, but now I'm thinking to myself - should there be voltage with engine not running? I suppose that if voltage is present, the injector is open, so it would let the fuel in the engine. Injectors are closed until I crank the engine and it is running. The problem is when I start to crank the engine, because they're giving just too much fuel, so either it stalls or barely starts and runs really, really rough (now it won't start, because it is flooded, also the spark plugs are probably really bad after few tries and they need to be cleaned for now, and of course changed in future).

There is one other thing that I've accidently found out and I think that it is very important too! When I was checking wires, voltage etc. I was turning the key on and off several times. After each time there was a 'clicking' sound coming from the engine bay. I knew that A/C compressor is making that kind of sound, but these sounds were somehow different. I've discovered that the active cylinders solenoids are clicking with key on! As far as I know, when these solenoids are energized the particular cylinders are being deactivated. I've checked the voltage on all four of them and after turning the key to 'ON' position, only both right (passenger side) solenoids are getting power supply. This car isn't supposed to disable cylinders when in Park, so there is a problem - Maybe this problem is caused by the bad ECM? Do anyone know what else can cause this to happen?

Replying to: 1979 Eldorado
You've really got me with this one, but it is indeed perfect saying for this situation. We're always encountering problems in our lives, but We need to keep on going forward and not looking back. Faith really helps out. In my case other Cadillacs owners are helping me a lot too . If you already read what's above, you know that there is another strange problem that I've found out, so You're right that it would be interesting to know what's wrong with this ECM, because it is getting more, and more mysterious. Maybe after some time my curiosity will strike and I'll go deeper into ECM - Who knows?

Replying to: Dave
I've seen Your message on Monday, and without much thinking I've just bought this nice set. You're right that they're worth it, not only because the price is very attractive but they are in such excellent condition. Unfortunately estimated delivery date is the end of May or the beginning of June, so if any further diagnosis will need some charts or schemes, I'll be very grateful for Your scans. Thank You for finding this manuals set, it is good that there is somebody like You with such a great knowledge about V8-6-4 Cadillacs.

Now it's time for me to go to sleep, because it is already after 9:30 PM. I'll be patiently waiting for Your thoughts and ideas about the new problems that I've found. Have a nice day. See Y'all tomorrow.

- Peter​