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Discussion Starter · #1 ·
Guys,

I'm having trouble getting my 69 mustang to idle when I put the A/C on. I have a 302 with a moderate sized solid roller cam and 4 spd. i live in Texas so a few yrs ago I put a vintage air system in. It idles fine at around 1,000-1,100 until I put the A/C on and then the idle drops way down to 400-500 and I need to tap the gas to keep it running. In order to get it to idle ok with the A/C on I have to turn the idle up to 1,500 with the A/C off. It is especially a pain when I stop for red lights/stop signs as the car wants to stall. Other than that the car runs fine. Any thoughts?

Mike
 

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You could simply put in a solonoid that kicks up the idle (pushes on the carb linkage) when you turn on the A/C. This was a typical arrangement for many stock engines and carb brackets and solonoids are common. The A/C unit may even have a "switch" that comes on with the compressor just for this purpose.

Actually, isn't this the beastie from a Ford Mustang of your year with your engine?


http://www.ebay.com/itm/New-67-68-6...t=Vintage_Car_Truck_Parts_Accessories&vxp=mtr
 

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Discussion Starter · #3 ·
Thanks for the feedback. Actually, I have a Mallory Unilite distributor with mechanical advance, and the distributor is already set up exactly as you suggest: 26 initial with 36 total, all in at around 3000ish. I rebuilt the 750 carb and was able to eliminate all the problems I posted about previously. Now the car runs well, except when the air is on. I think I will look into putting in the A/C solenoid you suggest. I was not aware that even factory cars came with those. It makes sense and I think it will take care of the problem.

Mike
 

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Discussion Starter · #4 ·
I'm not sure, but I understood that with the way my dist is set up the timing can never be less than 26 total timing. this dist has an adjustable advance timing limit. Currently it is set to give only 10 degrees advance. then I set the wieghts and springs so that the timing mark moves through that ten degrees when I rev the enginge, with full advance at around 3000. Then I power timed the car to 36 degrees. so AFAIK the most the timing can retard to from the peak is to 26 degrees, even if the idle drops down to zero the timing can never be less than 26 degrees, correct?

Thanks for the info on the solenoids. I will be sure to pick up the right one. I think that will fix the whole problem.

Mike
 
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