gpbeau Posted July 10, 2014 Share Posted July 10, 2014 I posted recently about an A/C clutch problem which the geniuses here helped to solve. Now there is another gremlin. When I bought the car ('72), the fast idle solenoid was inop--dead. Just got a replacement, installed it and plugged in the connector and 'click'--the plunger pushed out. This was with the A/C control in the off position. No matter what function is selected, that solenoid is receiving power. Is this supposed to be on only when the A/C clutch is on or is this an anti-dieseling solenoid? If it's only supposed to be on with the clutch, any recommendations where to look to see why it's getting constant power? Thanks in advance. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted July 10, 2014 Share Posted July 10, 2014 anti dieseling Quote Link to comment Share on other sites More sharing options...
stangeba Posted July 11, 2014 Share Posted July 11, 2014 FYI: On my 71 NO A/C 350 4BBL the solenoid is hooked up to the TCS and was energized only when the transmission shifted into 3rd (high) gear, to lower emissions when you let up on the gas. To adjust the solenoid you shifted the trans into Reverse with the engine running, where it also energized the solenoid. The other function was, vacuum was only able to pass through the solenoid to the vacuum advance when it was energized (3rd or high gear) 72 changed, I know they had a TCS vacuum advance shut off on the right side of the intake. Mine was all removed sometime in May of 1971 and I run ported vacuum to the advance canister. Bruce Quote Link to comment Share on other sites More sharing options...
Toppless72 Posted July 11, 2014 Share Posted July 11, 2014 On a 1972 the idle control solenoid does not have a vacuum connection. On the '72s the solenoid is energized at all times the key is on. It holds the throttle plates open the desired amount to insure proper idle and the "off idle" throttle response. Once the key is switched off it is de-energized allowing the throttle plates to close completely choking off all air to the engine thus, preventing the dieseling effect. It is powered from Circuit 141. It shares its power with the transmission control solenoid and the transmission switch. However, it does not send or receive a check signal to or from either of them in order to function. It is pin DZ on the engine harness bulkhead connector (dark blue wire). Quote Link to comment Share on other sites More sharing options...
gpbeau Posted July 11, 2014 Author Share Posted July 11, 2014 Thanks to all who replied. Sounds like this is operating properly on my car. Now it's time to set up the proper idle speed with this thing energized. Quote Link to comment Share on other sites More sharing options...
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