It's THROTTLE bodied fuel injection
Rather quaint way, but nothing wrong with that.
I had an '78 (last big one), and it was great; only trouble I had was with the four corner bumper ends that seemed to be made out of adobe.
That car was like driving a cloud.

Alas, it burnt to a crisp in a fire last year. (along with 7 other cars))

 

These photos are very sad. My condolences.

 

I like TBI OBD1 easy to troubleshoot, both My jeeps were converted to carbs to TBI

 

There is pretty good support in the Cadillac community for the "70's EFI". You should certainly buy the white and Blue Cadillac EFI manual. There's also a member on the Cadillac and LasSalle forum who posted it. See post nr 6 of this thread:

EFI manual differences 1976

EFI manual differences 1976

forums.cadillaclasalleclub.org

Try to get the maintenance history. As mentioned it is a TB but it has 8 individual injectors which open in groups of 4 and NO it's not OBDI.

There is a member who is an expert on the ECU's and he also recommends adding an external fuel pump relay as a preventative measure. I added one to my 1979 and did a write-up on the C&L Forum.

There are certain issues which can occur which are very easily recognized. One is a cold start issue which is almost always due to the 2 wire coolant temp sensor. I researched those with forum help and I was able to recreate a replacement and one which we believe addressed the common failure modes.

My car made me nervous to start but I now like the system. It's also funny because there are some people who don't understand them but assume if it had a carb it would be better... only to find out the issue they have/had really wasn't specific to EFI. Anyway if you have any issues ask and also look at the diagnostic trees in that white and blue manual.

Scott

 

What a loss. Those photos must be hard to look at.
from grilling the owner he said the car does require a warm up period to accelerate properly. He also mentioned he thought it ran a little rich. He got the car from his cousin this spring so is not that intimate with it. Prior to that it was in the family in laws …..

 

The fuel injection is a good negotiating point on price. 79 Eldorado knows these things inside and out so you will be in good hands-BUT all aspects related to its care and feeding will be specialized operations that a run of the mill mechanic will not be able to do without your direct involvement in procuring parts and executing repairs-we can help you here, but you will be involved in making it run right. Be aware that a 1977 fuel injected Eldorado is the only year of that body and engine that is fuel injected and very few were made. 79 Eldorado could probably speak to this more in depth, but I am sure that if there are 1 year only parts that no longer exist, that is the car that has it.

When working properly it is a very nice system and helps the engine to idle and accelerate off idle a lot nicer than the carbed big block Cadillac was known for. However I would venture that none of them in the wild today outside of the hands of a few nuts like us on this message board run “right”

He mentions the car runs rich-so internal engine damage is very possible if this condition has been happening for a while (and it probably has not worked right since about 1986). For some reason when these things run rich, it is RICH, like exhaust fumes that make your eyes water. This will wipe cylinder walls and wreck cranks, especially on a Cad big block thats had the extra meat cut out of it (77+ 425 & 368)

It is also of vital importance that he isn’t smelling raw fuel leaking and confusing it for a rich condition. This system pushed and exceeded the limits of what was available in terms of materials and experience at that time, and high pressure fuel leaks are orders of magnitude more common in the 70s fuel injected cars than anything else I can think of. Usually results in a picture not unlike that sad scene Harry posted above. The demand for front end parts for 76-79 Sevilles (which had this system standard) has always been strong for this reason (engine fires).

In short, my opinion (who asked anyway?)-make sure the rest of the car is in excellent condition, and know that you are buying into an orphan engine and orphan system that will require you be very involved in its life if it is going to work.

 

Anthony/All,
Why is the 77 a one year only? The EFI system was officially on 1976 Eldorado, the only engine offered on Seville (different engine though) and an option on anything with the big Cadillac engine. We've found enough 1975 owners to know that it was also available on the big Cadillac engines in 1975.

Good point if someone is continuing to drive it rich. There are a couple of very easy things to check immediately:
-Is the vacuum line to the ECU cracked, not sealed or missing. That line goes to the MAP sensor inside the ECU so if the vacuum single isn't received then the ECU will interpret it as a condition where vacuum is lost WOT.
-Check the coolant and air temp sensors. It's not as common of a failure mode but if the sensors read too low, especially the coolant temps sensor, it would run rich. I recently discovered that the air temp sensor on my car which I removed now 4 years ago was not original. That sensor was a different design and it read about 60% low. I needed to replace both of mine.
-Check the vacuum line going to the fuel pressure regulator. Again if there's an issue the low vacuum would make the car think it needs more fuel.
-If all of that is fine then you may have an injector which isn't sealing or a plugged fuel return line. Bruce Roe normally recommends attaching a fuel pressure gauge and then turning the ignition to run to pressurize the system (do not start; do not crank). The pumps only run for 2 or 3 seconds so best if someone can turn the ignition and you can watch the gauge. If you see the gauge gets to around 39psig (37-42) but then drops fast when the pumps stop an injector(s) is probably leaking. The restricted return line is probably less likely but if the fuel pressure doesn't drop off it could still be the return line. I suspect the pressure reading could be high but hold in that case (I haven't tried it though).

I need to stop doing this off the top of my head and checking the troubleshooting manual after... The failure mode common causes also list electrical connections as nr 1 and mention look for shorts. I don't know what they have specifically in mind but a short of the coolant temp sensor wires to each other would act like too low resistance. Anyway I will attach that common cause matrix, the index and the rich condition tree plus the cover of the book I'm referring to. The OP should have a copy.

Scott
Edit: Most of us use the manual I posted the cover image of but there is also a brown cover manual.

 

Anthony/All,
Why is the 77 a one year only? The EFI system was officially on 1976 Eldorado, the only engine offered on Seville (different engine though) and an option on anything with the big Cadillac engine. We've found enough 1975 owners to know that it was also available on the big Cadillac engines in 1975.

Scott, you would know more than me what changed year to year, but 77 was the only year for a 425 fuel injected Eldo. Don't know what if anything changed between the 500 and 425 system, but would imagine something had to give.

Thank you 79 Eldorado for all the time and great advice. and everyone else who took the time to chime in. The response from this group has definitely influenced me to move forward and get into the Eldorado club. I’m heading from Maine today down to Hartford conn. I hopefully like what I see and will be driving the car back to Maine (176 miles)this afternoon. It’s not a show car but has been garaged and looked after …I’m told.

If you end up buying the car, I would really consider towing it back depending on how rich it runs. You can do a lot of damage going that distance under load if its dumping gas.

 

Thank you 79 Eldorado for all the time and great advice. and everyone else who took the time to chime in. The response from this group has definitely influenced me to move forward and get into the Eldorado club. I’m heading from Maine today down to Hartford conn. I hopefully like what I see and will be driving the car back to Maine (176 miles)this afternoon. It’s not a show car but has been garaged and looked after …I’m told.

 

I agree with Anthony regarding getting it back to Maine. I would either tow/transport it or diagnose it further. Besides the EFI you also need to consider basic things like brakes, tires and suspension. Cadillac also seemed to bless owners with no option for gauges. To me every car should have at minimum a temperature gauge and an oil pressure gauge. I'm not a 77 expert but you likely have nothing other than a fuel gauge.

I would see if the seller can recommend a local garage or perhaps one of the members can. I've had a couple of individuals buy sensors from CT but in many cases I don't have direct contact through the selling site. There is one member who I could phone in Norfolk which seems to be less than 36 miles away. Maybe that member could suggest a garage near his area. He owns a 1976 with EFI so he might be willing to pop-in and give you updates.

Scott

 

Anthony,
The 425 shouldn't have driven much which was unique other than the ECU "tune". Bruce would need to comment on that. I had to check online to see how long the 425 lasted. It looks like it continued to 1979 in some Cadillacs and other Cadillacs were offered with EFI. Bruce can as well take a "small car" ECU and rework it into a "big car" ECU. The only thing he was missing were the unique mounting brackets but I reproduced the unique brackets for him and as a bonus I made them from stainless steel. Anyway I think Bruce would say the ECU shouldn't be a show stopper. I would however never use my original ECU to avoid a core charge. Bruce can fix most common failures. He does recommend having a spare though as a just-in-case.

I hope Ward sees my message above. It seems like a really bad idea to drive it without having it checked out. I would flatbed it to a garage near that other member assuming he knows of one to recommend. He drives his car often during the non-winter months.

Scott

 

Thanks everyone. I ended up not buying the car. Lots of weeping fluids under the hood ,smelled like fuel , completely inop hvac system, interior pretty beat up. Drove ok tho and was a hoot. Something about these Eldorado. Currently looking at a cleaner 1976 , carborated, current owner has a list of recent service, of course the ac doesn’t work. We’ll see how this goes