2021 Article on Cadillac 70's EFI -Curb Side Classic VinceC

[79 Eldorado]

I came across this article while trying to verify whether or not Cadillac used the system specifically on any '78 Eldorados. As I recall another member mentioned it wasn't listed as an option not too long ago. I do have Bruce's ECU PN list and for 1978 the C and the K are listed but nothing specifically for 78 E.

When I saw it I immediately looked to see who wrote it thinking it might be someone from this forum. I thought some others may enjoy it:
Automotive History: 1975-1979 Cadillac Electronic Fuel Injection – GM's (Gladly) Forgotten Fuelie – A GM Deadly Sin?
BY VINCEC – POSTED ON JULY 30, 2021
https://www.curbsideclassic.com/automotive-histories/automotive-history-1975-1979-cadillac-electronic-fuel-injection-gms-forgotten-fuelie/

He has a nice photo of both a big Cadillac intake and the Olds intake with only the fuel rail set-up.

Someone outside the US bought a sensor today for a 1978 Eldorado. While not everyone identifies their vehicle type this may have been the first 78 Eldorado identified. That said some countries list the model year by the year the car was built so it's possible this car would not be considered a 1978 in the USA.

Scott

[bcroe]

That article is reasonably accurate.  What nobody mentions, is that
electronic technology was in big evolutionary changes at that time
(I was designing phone office equipment at the time).  Simple
transistor systems were being replaced by much more capable
systems using Integrated Circuits, powerful building blocks each using
many transistors in a carefully optimized design.  The 70s Cadillac EFI
was just in time to utilize the first generation of consumer grade ICs, to
considerable advantage. 

Yes it did use a completely electronic MAP sensor, which meant it
outclassed everything that did not.  Unfortunately the MAP was a very
poor mechanical design, prone to failure over time.  MAPs continued
to evolve into very reliable parts of newer systems, using the evolving
power standard of +5VDC.  The Cad EFI used +9.5VDC internally,
there were no standards in 1970. 


The 70s EFI system was assembled much like radios of the era.  But many
of the components were then state-of-the-art.  The art was changing very
fast, and for 1980 the entire analog system was dropped for programmable
digital systems, using parts that did not exist a decade earlier. 

I do not see the EFI providing nearly the advantages hyped on the old iron. 
Rather, it gave the General some experience in dealing with new emission
standards, and in anticipation of managing far advanced engines soon. 

Bruce Roe

[79 Eldorado]

I decided to comment on the article. Mine is so far down I'm not certain if anyone else will see it. I wanted to let the readers (and the writer) know there are a lot of the 70's EFI systems still in service, that some of us are trying to make them reasonable to maintain and finally that there are some helpful sites like the CLC forum and the cadillacseville org site:
http://www.cadillacseville.org/technical.html

Bruce mentioned the there were no standards for the reference voltage to use at the time. It's always interesting to see how standards evolve. In general it would be interesting to hear more in depth history of the development. Even though these were batch fired injectors and no feedback I always thought they were ahead of their time from the perspective of eventually the industry got back to individual injectors but it took a long time.

I posted the link once before but there's a description in the Cadillac technology marketing video of the 70's EFI system starting around 2min 42seconds here:
https://www.youtube.com/watch?v=qF2FljYIOFk

[bcroe]

One thing mentioned but little appreciated in the sales video, is the
use of laser trimmed resistors.  They are a custom, expensive
operation required to produce initial and lifetime precision in an
analog computer.  I have found the originals to keep their accuracy
to this day.  They are one reason those ECUs are interchangeable
parts, some other products required adjustment for each engine. 

The later digital systems eliminated the need for these expensive
resistors, and the feedback loops with extensive memory allowed
each digital ECM to fine tune itself to each engine.  Bruce Roe

[Eric DeVirgilis CLC# 8621]

I came across this article while trying to verify whether or not Cadillac used the system specifically on any '78 Eldorados. As I recall another member mentioned it wasn't listed as an option not too long ago. I do have Bruce's ECU PN list and for 1978 the C and the K are listed but nothing specifically for 78 E.

That is correct - FI was dropped as an option on the 1978 Eldorado for unknown reasons but remained optional on RWD models with 425 engine until 1979.

[79 Eldorado]

That is correct - FI was dropped as an option on the 1978 Eldorado for unknown reasons but remained optional on RWD models with 425 engine until 1979.

Eric,
And to add to what you wrote EFI was standard on 1979 Eldorado for the gasoline variant. So EFI was really only gone on the Eldorado for the final year of that generation. It really seems strange.

It would be really interesting to know what the person has who bought the sensor. Maybe it's a '79 MY built in 1978. In some countries they would consider that a 1978. I hope that the car they purchased it for is actually an EFI car.

The EFI option couldn't have been continued for 1978 cars built for sale outside of the USA could it?

Scott

[Eric DeVirgilis CLC# 8621]

Yes the Olds 350 FI became standard in the next gen ('79) Eldorado just as it had been in the Seville since 1976. 

I see no reason why FI would have otherwise been discontinued as an option in export (RWD) models but I claim no expertise in that department. Why the option was dropped in the '78 Eldorado remains a mystery for the time being.