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Discussion Starter #1 (Edited)
I bought my '72 SS as a numbers matching car several year ago. Shortly after I found the carb was a '78, but it ran great, so I left it alone. Since then I've looked for an original 7042202 and finally just found one. I haven't rebuilt it yet, but I noticed the "72 Q-Jet has an idle speed solenoid with a male electric plug-in. The '78 doesn't. I don't see a wire to connect the '72 Q-Jet and I'm asking if I can run without the ISS. I don't have A/C, only drive on nice summer days and I've seen '72 cars without them at car shows, but never thought to ask. At first glance, it seems unnecessary, plus it looks better without it hanging out there. Thanks.
 

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^^ditto^^
just keep it on a shelf for future mind change,if your like me youll forget where you put it:rolleyes:
 

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Wasn't that for the AC cars? If your's isn't a factory AC maybe that's why it's not showing on your wiring? Anyways like stated just shelve it or leave it on the carb, it won't show up with the breather on.
 

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Discussion Starter #6
Idle speed solenoid

I bought my '72 SS as a numbers matching car several year ago. Shortly after I found the carb was a '78, but it ran great, so I left it alone. Since then I've looked for an original 7042202 and finally just found one. I haven't rebuilt it yet, but I noticed the "72 Q-Jet has an idle speed solenoid with a male electric plug-in. The '78 doesn't. I don't see a wire to connect the '72 Q-Jet and I'm asking if I can run without the ISS. I don't have A/C, only drive on nice summer days and I've seen '72 cars without them at car shows, but never thought to ask. At first glance, it seems unnecessary, plus it looks better without it hanging out there. Thanks.
OK, I'm going to leave the ISS off. Thank you for the input and support. Sure is nice to be able to run these questions by some other Nova guys.
 

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Wasn't that for the AC cars?
Some non-AC cars had them too.

On non-AC cars they were used as an anti-dieseling solenoid. It's shown on the factory wiring diagrams as an "idle stop solenoid" (circuit #141) 20ga tan wire.

They're powered from the same fuse as the radio so the solenoid plunger is extended (and sets the base idle speed) whenever the ignition is on. When the ignition is switched off, the solenoid plunger retracts and lets the throttle close against the idle speed adjustment screw on the carb. And that is supposed to be set to a really low idle speed (like 450 RPM) to make sure the engine shuts off without dieseling.

My 74 (non-AC car) had one of those idle stop solenoids with the original 2bbl carb. I swapped to an older Q-Jet that didn't have a solenoid and don't have any problems without it so I just taped the unused wire back to the harness.
 

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I put one of the Summit one's on an old 69 Chevy truck I built and just powered over from the AC compressor so it would kick the idle up to whatever you adjusted it to.
 

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Some non-AC cars had them too.

On non-AC cars they were used as an anti-dieseling solenoid. It's shown on the factory wiring diagrams as an "idle stop solenoid" (circuit #141) 20ga tan wire.
the heavy work trucks had them for that very reason.
 
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