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Drops out of fast idle too soon.

 
Old 06-12-2019, 09:22 PM
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Redvette2
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Default Drops out of fast idle too soon.

Car starts wonderfully...a few seconds of crank and off she goes. Doesn't matter if sitting for two weeks cold or a hot restart. At first start the fast idle works correctly but the second I give it a little gas to back out of the garage it drops down right away before the car is warmed up and then car acts balky for a few miles. Once warm the regular idle is fine. The carb is a Eldelbrock 600 and it does have a cam but type is unknown. Has a HEI distributor also. I have adjusted the idle screws and the choke opening but no effect.

Is there an adjustment to keep the fast idle engaged longer?

Thanks,
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Old 06-12-2019, 10:15 PM
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drwet
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The only way to adjust that is to adjust the choke. The problem with that is the car might not start quite as well if you dial in more choke. I have the same problem with my Holley. My plan is to install a switch on the wire to the choke coil. This will allow me to turn the choke's heating coil off for a minute or two after I start the car cold.
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Old 06-12-2019, 10:55 PM
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Originally Posted by drwet View Post
The only way to adjust that is to adjust the choke. The problem with that is the car might not start quite as well if you dial in more choke. I have the same problem with my Holley. My plan is to install a switch on the wire to the choke coil. This will allow me to turn the choke's heating coil off for a minute or two after I start the car cold.
Choke heating coil....perhaps there is a way to fool it longer. Less voltage or lighten/lengthen a spring or?

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Old 06-12-2019, 11:51 PM
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Are you sure the choke is opening in a few seconds? I'd have assumed that takes minutes to happen. I'd look there, first. Perhaps run the engine, watch the choke, and see if you can pick up what is moving that enables the fast idle cam to drop away. If you goose the throttle all they way, can you get the fast idle setting back (as you would with the two pumps before you start the car)?

If you do decide that a delay trigger for the electric choke is needed, perhaps you can wire it to a coolant temp switch that closes WELL before your thermostat opens. 120 degrees, or even cooler. That way you won't have to remember to set a switch position twice each time you drive the car.

Last edited by Bikespace; 06-13-2019 at 12:02 AM.
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Old 06-13-2019, 12:04 AM
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It really is quite quick as I like to pull the car out right away to keep the wife happy (runs a little rich). When I look at the carb I see that the throttle position is off the fast idle cam. I will try the pumping it again to see if it resets. Just seems like something is not set right. I will look on the passenger side of the carb and see what changes.

Edit: Another possible clue...my alternator/regulator is typically running high 14.9 to 15.2 volts at start. I wonder if this causes the choke heater to warm up faster.

Thanks for the suggestions,
Redvette2

Last edited by Redvette2; 06-13-2019 at 12:09 AM. Reason: Another possible clue...
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