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1976 eldorado convertible
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Discussion Starter #1
I have a 1976 Eldordo with factory EFI. Am curious to know what the expert opinions may be on if the EFI should be swapped for a carburator? How reliable are the old EFI's and how available are EFI parts etc?
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Hang tight - which engine are we talking about ??? (500, 472, 425 ???) If you get no answers here we can move this to the Engines forums.

Welcome Aboard !!! :highfive:
 

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1976 eldorado convertible
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50 Posts
Discussion Starter #3
Thanks for the welcome am looking forward to being part of the fun. The engine is the 500 cid................
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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I have a 1976 Eldordo with factory EFI. Am curious to know what the expert opinions may be on if the EFI should be swapped for a carburator? How reliable are the old EFI's and how available are EFI parts etc?
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if the EFI should be swapped for a carburator
the original EFI system was SO bad - they made a carb-swap kit -
and the vast majority did the swap -

if you LOVE to tinker - and REALLY ENJOY being frustrated -
stay with the EFI -

if - on the other hand - you would rather go for a nice - relaxing cruise -
put the carb on it -
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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OK - The general trend here in Seville/Eldorado is the Northstar engine. Let me move this to Engines, 500 etc., and see what happens.
 

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70 Deville 77 Fleet 78 Seville 92 Deville 03 Deville
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if the EFI should be swapped for a carburator
the original EFI system was SO bad - they made a carb-swap kit -
and the vast majority did the swap -

if you LOVE to tinker - and REALLY ENJOY being frustrated -
stay with the EFI -

if - on the other hand - you would rather go for a nice - relaxing cruise -
put the carb on it -
That's been my experience too. If the FI worked, I would run it as long as it worked good. Replacement parts are hard to come by though. I don't think I would trust it for a cross country trip either.
 

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1980 FBC
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3,215 Posts
My opinion is the carb cars never even came close to running as well as the injected Cadillac 500 or 425. They do take knowledge to keep running though.

I would sooner switch to a more modern injection like a Megasquirt than put a toilet bowl on top of the intake manifold.

If you are anywhere near Toms River NJ I'd be glad to take all those awful injection parts off your hands in exchange for installing the carby/intake/misc stuff.
 

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95 FWB 81SDV 96 FWB 94 Fleetwood
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The main problem with those old computers are they are old.. They say the parts are hard to come by, but I have a bunch of them.. There is a member of this board , Bruce Roe, that fixes the computers and some mods to keep them running with less problems... If I had your car I would just keep some spare parts on hand, like a spare computer and a few temp sensors.. I would take out the low pressure fuel pump in the tank and put in a high pressure pump.. That way you can take off the high pressure on the frame and just use one pump... And do Bruce's extra relay mod to run the pump to help save the computer...The only part that is hard to find is the fast idle heater valve... I had a lot of them , but there all gone now...
 

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1980 FBC
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The main problem with those old computers are they are old.. They say the parts are hard to come by, but I have a bunch of them.. There is a member of this board , Bruce Roe, that fixes the computers and some mods to keep them running with less problems... If I had your car I would just keep some spare parts on hand, like a spare computer and a few temp sensors.. I would take out the low pressure fuel pump in the tank and put in a high pressure pump.. That way you can take off the high pressure on the frame and just use one pump... And do Bruce's extra relay mod to run the pump to help save the computer...The only part that is hard to find is the fast idle heater valve... I had a lot of them , but there all gone now...
Good info. The 500 C.I. fuel computer is not as easy as the 350 or 425 to come by in my experience. Agree on the pump. The other liability is the fuel lines.

I'm fairly sure someone could adapt an external fast idle valve like some of the Euro Bosch EFI cars of the era used. Probably been done already.
 

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95 FWB 81SDV 96 FWB 94 Fleetwood
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Apeman... I have a used 500 computer that has been gone over by Bruce that looks the day it was made... Somebody will need it one of these days... I have a fuel injection set-up on a 472 run by a haltech... I made a fast idle replacement set-up... It is a solenoid valve that is closed by a timer circuit board and the haltech at a temp.. It closes when it reaches 150 F or if it is already warm it fast idles for 60 seconds...
 

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1980 FBC
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Apeman... I have a used 500 computer that has been gone over by Bruce that looks the day it was made... Somebody will need it one of these days... I have a fuel injection set-up on a 472 run by a haltech... I made a fast idle replacement set-up... It is a solenoid valve that is closed by a timer circuit board and the haltech at a temp.. It closes when it reaches 150 F or if it is already warm it fast idles for 60 seconds...
Farout. Any details of pix of the Haltech?
 

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I will be taken it out of storage sometime real soon for the summer.. The first week of april is pretty safe no more snow.. I'll take some pictures and post them then...
 

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1980 FBC
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I agree! I had a '76 EFI Fleetwood and it was the smoothest running Cadillac I've ever owned.
Especially at or just above idle. The uphill intake manifold on these engines may be the culprit.

When tuned for maximum economy 425s and 500s are not the best idling engines. Injection fixes this.

The major problem with that system was Cadillac didn't include a free shop manual with every one. The average mek-a-nik at the time could have very well have been seeing this as the first injection system ever in their shop.
 

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Eldorado
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448 Posts
The 76-79 EFI book you really want is on EB*Y a lot, like Item number:330668089237. I
have a couple spares too, cover smudged some. I also have seen the 500 ECU listed.
Though, the 350 ECU can be retuned as a backup (wrong brackets). I should put how to
do that on my PHOTOBUCKET. Bruce Roe
 

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1976 eldorado convertible
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50 Posts
Discussion Starter #17
yes i have ordered the efi diagnostic book. glad for the info tho you guys are great.
 

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76 Eldorado Convertible
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3 Posts
Hi, here in Brazil I have a 76 Eldorado EFI and tired of trying to fix the fuel injection source. I installed the FuelTech, which is a programmable fuel injection and had no more problems. All original parts have been exploited and appearance of the engine remained the same. For the 500 engine, the fuel injection models used are the FT 300, FT350 and FT400
Not cheap, but solved my problems.
Manufacturer's website http://www.fueltechems.com/home.html
 

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Eldorado
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Hi, here in Brazil I have a 76 Eldorado EFI and tired of trying to fix the fuel injection source. I installed the FuelTech, which is a programmable fuel injection and had no more problems. All original parts have been exploited and appearance of the engine remained the same. For the 500 engine, the fuel injection models used are the FT 300, FT350 and FT400. Not cheap, but solved my problems.
Manufacturer's website http://www.fueltechems.com/home.html
Did you use the same injectors at the same pressure? Still bank injection, or change to sequential? The same ignition, or an ECU programmed advance? Did you change the temperature sensors? How long did it take to get everything tuned up? Did you use an OX sensor? Did you change the idle air motor? Is your old ECU available for another Cad owner? Bruce Roe
 

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76 Eldorado Convertible
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Did you use the same injectors at the same pressure? Still bank injection, or change to sequential? The same ignition, or an ECU programmed advance? Did you change the temperature sensors? How long did it take to get everything tuned up? Did you use an OX sensor? Did you change the idle air motor? Is your old ECU available for another Cad owner? Bruce Roe
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Everything remains the original, except for the replacement of TPS, temperature sensor, idle air valve and coil. Hall sensor was adapted in the original distributor (before has a mallory distibuidor was installed but did not work out). The mechanic took about 3 weeks to deliver the car. Yes, I installed the O2 sensor. The original ECU I do not intend to sell. You should also install a Peak and Hold and Spark Pro 1
Sorry for the delay in answering and the errors in your language.

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