1979 Cadillac Eldorado Biarritz

[gordon24]

Well have a question.i have a 1979 Cadillac Eldorado Biarritz with 350ci with electronic fuel injected.i have a bad idle air control valve.having issues trying to locate new one.Im from Canada.Any sites I can check.also can they be cleaned.also does anyone have this model and can show pic of your idle air control valve.

[TJ Hopland]

We have a resident expert here on those systems that I'm sure will be along soon with more into than I have.    What I know about those is they are not like more modern ones that are a motor that the computer can fairly accurately control these are more like an electric choke.   Its a basic heater that just starts heating when the engine starts and then cools when it shuts off.  I do remember reading about shimming being a possible fix for some of their issues.  I have also read about someone that did fit a more modern one and then used an Arduino to control it.  An Arduino is a really basic and inexpensive mini computer that can be custom programmed to do simple tasks like this.  I don't recall what sort of mods it took to fit the newer valve, I think it involved cannibalizing the original to get the correct mount. 

[79 Eldorado]

Hi Roy,
I'm not the resident expert whom TJ mentioned but I also have a 79 Eldorado Biarritz. I'm traveling now but when I return I could try to take some pictures. I will be following your topic because it seems like even if you don't have an issue it is good to be aware of the symptoms in case of future issues. I think Bruce Roe is who TJ is referring to. He's already helped me on a couple of topics. He has a nice preventative measure fix for a common ECU issue as an example. I also recently fixed my trip odometer which had never functioned since I bought the car and as well I changed my heater core.

There is someone reprinting the 79 Eldorado service manual and selling them on eBay. I did notice the dash removal in the Cadillac Service manual lacks some information which I originally found in the '79 Oldsmobile manual but the Cadillac manual is extensive and almost double the thickness of the Olds manual. While it lacked the specific location of the key fasteners required for the complete dash removal it has still proven itself to be of value and I would recommend buying it. The Eldorado dash was different than the Toronado (Oldsmobile E-Body) dash in a couple respects but most of the fasteners were similar. Bruce also suggested getting the Electrical trouble shooting manual. I have it as well. It's something close to 11x17" format with a drawing of an Eldorado on the front cover. The originals still pop-up on eBay sometimes.

Scott

[bcroe]

That valve is a problem, no replacement parts to be found.  That little brass
pin in the center is supposed to push it closed as the heater warms up.  Try
to clean it up and see if it closes all the way, if not a shim something like
a dime might push it farther. 

A GMC motorhome guy machined a modern valve to fit in the same spot,
quite a bit of machine work.  Then it required a more modern ECU to drive
the motor, as well as the rest of the injection system.  good luck, Bruce Roe

[TJ Hopland]

I will see if I can find where I read about the mod.   For some reason I was thinking there was a Jeep connection.    The original thread was related to a Megasquirt ECU which replaced the original but then someone else had replied and linked to his project where he had the Arduino running the new valve with info from the old system.  It sounded like it worked well.  I think he was taking inputs from more places than the simple power on of the original so it was a little more accurate than the original.   I don't recall him talking about machining to the throttle body but it did take some fabricobbling of the 2 valves to make one that would bolt on.    It could have been a GMC thing, but I remember it being a 500 but maybe he had done a Cad swap also.   

[79 Eldorado]

It looks like there is one for sale on Cadillac King Parts
http://cadillacking.org/index.php?main_page=product_info&cPath=32_34_122&products_id=121

They are asking $297 but there is a refundable deposit of $95 so I suspect they might be rebuilding them. Why else would there be a deposit?? If this is the correct part they have a good photo and they list the part from 75-79 for Coupe/Sedan DeVille, and Fleetwood as well as 75-80 Eldorado and Seville.

Scott

[79 Eldorado]

I also found this Feb 2012 thread from this forum with some more discussion and very good photos:
http://forums.cadillaclasalleclub.org/index.php?topic=118518.0

The description in that thread makes it sound like these are filled with a wax similar to thermostats (could very well be a different melting temperature wax though).