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Discussion Starter #1
I'm trying to correct the idle on my '87 Shelby Charger T-1. I've replaced all the vacuum lines, some more recently than others. I replaced those associated with the PCV this week and idle dropped from 2300 to 1800. It needs to be 900.

I set the AIS manually to about 1/4". That's how it used to run correctly. On start up, the engine idles about 1000 rpm. As the engine warms, the idle rises. One can even watch the temp gauge and tach needles go up at the same time until idle peaks at 1800 rpm.

Does the AIC motor assembly need a gasket? there was none on my car when I bought it. It did run fine for a few years before this condition started.

When this started to happen, I checked for codes and there were none.

Is anyone familiar with this condition and have an idea of something I've overlooked?

Thank you
 

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Discussion Starter #2
I'm trying to correct the idle on my '87 Shelby Charger T-1. I've replaced all the vacuum lines, some more recently than others. I replaced those associated with the PCV this week and idle dropped from 2300 to 1800. It needs to be 900.

I set the AIS manually to about 1/4". That's how it used to run correctly. On start up, the engine idles about 1000 rpm. As the engine warms, the idle rises. One can even watch the temp gauge and tach needles go up at the same time until idle peaks at 1800 rpm.

Does the AIC motor assembly need a gasket? there was none on my car when I bought it. It did run fine for a few years before this condition started.

When this started to happen, I checked for codes and there were none.

Is anyone familiar with this condition and have an idea of something I've overlooked?

Thank you
Also, if I pull the PCV and plug it, rpm drops to 900.
 

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Since the idle speed is normal on cold startup we have to "assume" the AIS itself is OK.
First you need to verify that base idle is correct and TPS voltage is not over 1.00 volts at closed throttle.
If both are correct then you still have a vacuum leak in the system.
There are O' Rings on the AIS.
 

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Discussion Starter #4
Thank you for the response.
he AIS has always been sketchy. Some years ago, I set it by hand at about 1/4 inch and it worked fine. About every two years, I had to pull it, clean it, and reset it to the approximate same. It worked fine and passed Ca smog every time. I'm not sure it works, but setting it by hand always got it. Is it 12v? If so, I'll jump it to see if the motor turns.

Which wire for hot to test the TPS?

Thanks for the info on the O-ring sets. I'm pretty sure there are only two on this AIS. The ad indicates there are three in the set.
 

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You need to backprobe the "Signal" (OR/DB wire) and "Signal Return" (BK/LB wire) lines at the TPS connector to read TPS voltage.
Closed throttle voltage should be between .30 - .90 volts.
Voltage will increase as the throttle is opened.
WOT = voltage above 3.50 volts.

ELECTRIC-TPS Connector 85-86.jpg
 

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Since the idle speed is normal on cold startup we have to "assume" the AIS itself is OK.
First you need to verify that base idle is correct and TPS voltage is not over 1.00 volts at closed throttle.
If both are correct then you still have a vacuum leak in the system.
There are O' Rings on the AIS.
My 86 T1 AIS hissed like a vac leak and didn't have a o-ring so I glued around it. oops...
 
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