Lit-Bern

Late 77 L 48
Where does the electric connection for the Idle stop solenoid come from? I have just rebuilt my Q-jet and the ISS was not connected ever since i have owned the car. The only diagram showing ISS is the A/C wiring diagram, and I do have a double green wire to a single connect lose at the A/C harness.
Any help

R. Bruno

I think that is an AC solenoid - same thing as the idle stop, but comes on with A/C. I don't think it had an idle solenoid :cheers:

Lit-Bern

I thought the ac at first it just dosnt seem right that the wire would come across the front of the motor to the opposite side of the carb.

If someone with a Rochester could look at the solenoid on the front drivers side of the carb. and tell me what color the wire is and where or what harness it runs to that would help alot.
Thanks

Shark79

When I had the Q-jet on my 79 rebuilt I thought they forgot to replace the A/C solenoid. After further review I found that GM didn't use an A/C selenoid on Vetes with manual trannys in 79.

kenko74

On my 74 L48 w A/C, the ISS is connected to a single post tan colored wire, and it's part of the engine wiring harness. Wire feeds forward from the driver's side firewall, over the valve cover, to the carb.


[Modified by kenko74, 12:33 PM 3/12/2004]

Freepop

:iagree:

vettfixr

On my 74 the idle solenoid is part of the harness. This solenoid was used to set the idle speed and assist is preventing run on caused by the lean mixtures of the time. The idea was to close the carb completely thereby preventing run on. I changed my setup to kick on only when the AC was active. i spliced into the green compressor clutch wire and connected that to the solenoid. I then set the idle speed by the screw on the carb. Now when the AC kicks on the idle solenoid raises the engine speed to the same speed that is set by the carb screw so there's no drop in idle.

Bill Oxley

vettfixr, I was looking at the 74 shop manual, and it says what you are saying. The purpose of the ISS was for "run on" and didn't mention a/c at all.

However, I think your approach to this minor mod is great! Terrific idea! I don't have any "run on" problems, so why not use the ISS for something needed. Good job!

:smash:

marshrat99

My 79 with automatic has a soleniod for increasing the idle when the AC is on. A green wire runs to the soleniod from the AC compressor. :cheers:

vettfixr

Thanks Bill. It made sense to me too. I never felt like the cure to run on should be a solenoid. Seems like it would be better to cure the lean problem and prevent it. :thumbs:

Lit-Bern

thanks guys thats got to be it-the green wire coming from the AC compressor is the only wire unaccounted for. I guess I read the diagram right after all. My boys Jeeps lift kit is finally done now some time with the wife and then back to what makes me happy.