1976 Eldorado with a ruff idle.....

[flw004]

Fellows, I need some help.....My 1976 Eldo was running great until I had a A/C controller replaced.  It doesn't seem that the two are connected but it's all I have to work with.  The car now has a ruff idle.  Otherwise it runs just fine.

What I've done so far is replace the plugs and wires, check the timing and idle speed.  All the vacuum hoses appear to be fine.  I appreciate any advice you may have........

Thanks,

[n2caddies]

I suspect a vacuum leak somewhere. Check with your device manual schematic and make sure everything us where it should be. You may be able to hear a leak in the dash as you turn on the AC controls. Check all the fittings on the carb and distributor advance.
Randy

[flw004]

Will do.  Thanks Randy......

["Cadillac Kid" Greg Surfas 15364]

Aside from those suggestions be aware that the rear compressor bracket bolts to the intake manifold, and if the bolts are not in, tight, un-stripped and sealed, you can get a vacuum leak at those points.
Greg

[TJ Hopland]

Does a 76 have a fast idle circuit that engages with the AC?   Perhaps changing the controller changed how that solenoid operates?   Maybe before it was stuck on but the repair got it off or stuck off?

["Cadillac Kid" Greg Surfas 15364]

TJ,
They quit putting an "AC Idle speed step up" on the cars stareting, I believe, in 1969 with the 472/500/Quadrajet.
Greg

[Scot Minesinger]

100% correct, 1968 was last year of the vacuum fast idle speed up when a/c is energized.  Vacuum leak is most likely source of fast idle.