1979 Cadallac Eldorado parts

[Spazz99]

Not sure if im posting in the right location. But i require some assistance finding a part.

I believe its called an exsaust back pressure transducer, or a choke pot.
There are some black painted on numbers on the top  1617117 055 last digit is unknown.

[Spazz99]

picture

[TJ Hopland]

Must be part of the EFI system,  I assume yours still has EFI?     

I'm sure Bruce Roe will be along soon and know what that is and does and if you can still get them or replace it with something.   

[bcroe]

That is part of the EGR control system of that EFI system.  Rather troublesome, some parts
seem to always to have failed (corrosion) and I doubt they are still available.  Rather than
fool with them when I got the car (1995), I observed it had an Olds 5.7L engine.  All my other
5.7/6.6 Olds of the era have a very simple EGR control system with a plastic valve above the
water pump; I installed one of these trouble free controls instead.  Maybe it had an effect, I
haven't noticed. 

Bruce Roe

[Spazz99]

Would u mind taking a picture of that. My eldo chokes out when u first hit the throttle but ince you gain a few rpm it runs like a top. Im thinking its cause this piece has broken off from the small brass tube it connects to. Im going to try soldering it on and see if i can repair it. But if not id like an option to delete it. I am tempted to convert it to a 4barrelcarb nd intake.

[bcroe]

Would u mind taking a picture of that. My eldo chokes out when u first hit the throttle but ince you gain a few rpm it runs like a top. Im thinking its cause this piece has broken off from the small brass tube it connects to. Im going to try soldering it on and see if i can repair it. But if not id like an option to delete it. I am tempted to convert it to a 4barrelcarb nd intake. 

My camera may have broken, had trouble last time.  The Old is just a vac hose from ported
vacuum, to the little valve clipped over the water pump, to the EGR, that other stuff removed. 
Generally EGR won't have that much impact.  I wonder if your ECU passes the 21 click test,
and if the timing chain is close to failing?  Some these cars get converted to a carb, but its a
lot less work to just fix them.  Your ECU could have issues. 

If you go to the first album on my PHOTOBUCKET, 70S FUEL INJECTION, there is a sub album
EGR REPAIR on fixing your parts, by Waldo du Toit.  There is other stuff on the 79 Eldo in
other albums.  Bruce Roe

[TJ Hopland]

If that device is some sort of a delay or lock out valve for the EGR I could see it causing the problem you describe.  IF the egr valve is opening at idle or initial acceleration it will cause issues.    I assume on these the vacuum source is a port on the throttle body rather than a solenoid via the ECU?  If so another thing that can cause egr issues is if the idle air system is not working and someone compensated by setting the throttle stop higher.   It could be high enough that the vacuum port for the egr is active when it should not be.    The faster the engine is running the less effect the egr will have on it. 

[bcroe]

If that device is some sort of a delay or lock out valve for the EGR I could see it causing the problem you describe.  IF the egr valve is opening at idle or initial acceleration it will cause issues.    I assume on these the vacuum source is a port on the throttle body rather than a solenoid via the ECU?  If so another thing that can cause egr issues is if the idle air system is not working and someone compensated by setting the throttle stop higher.   It could be high enough that the vacuum port for the egr is active when it should not be.    The faster the engine is running the less effect the egr will have on it.

I never really understood exactly how the EGR might work or go wrong.  Active part throttle,
NOT idle or WOT I understood.  Some of the 70s EFI cars have a solenoid output from the ECU,
some do not.  But all gave that mechanical control that bolts between the EGR valve and the
manifold, and it loves to break.  Bruce Roe

[Spazz99]

Ok i will look into the pictures. And how would i test the ecu? I believe its this part causing the issue. Someone has shimmed the idle adjustment at the rear of the throttle body (large black sylinode with the wires on it, spring and white valve plunger.) I was thinking of replacing that as its not suppost to be like thatm there shouldnt be shims and if you remove them the idle goes wayyy up. And the cars idling very high as it is. Probably around 800 or more.