Author Topic: Ignition switched feed for choke?  (Read 108 times)

Online Chevygold

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Ignition switched feed for choke?
« on: October 09, 2019, 07:28:37 AM »
Im fitting an auto choke to my Edelbrock carb in my 76 Cheyenne with 350 any suggestions where I can get an ignition switched supply under the hood?
Graham


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Offline Irish_Alley

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Re: Ignition switched feed for choke?
« Reply #1 on: October 09, 2019, 11:52:33 AM »
Oem setup would be from the oil pressure switch.
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Online Chevygold

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Re: Ignition switched feed for choke?
« Reply #2 on: October 09, 2019, 03:01:11 PM »
Thanks Irish sounds logical although I haven't found one yet, still looking for the oil gauge pipe as well, there's a pressure sender for an electrical gauge but dash gauge is still original.
Still quite a long list of things to do yet, at least all the lights seem to work.
Graham

Online bd

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Re: Ignition switched feed for choke?
« Reply #3 on: October 09, 2019, 03:32:26 PM »
The typical oil pressure switch for electric choke power is SPST-NO, non-grounding and has two prongs.



It is available in 1/8" NPT and 1/4" NPT thread.  Which switch configuration you choose depends on whether you want to mount it in the rear China wall of the engine adjacent to the distributor (1/8" pipe) or down by the oil filter (1/4" pipe).  You can piggyback power from the pink B+ wire that feeds the HEI distributor.

For information on the function of the factory electric choke, see GM electric choke operation for Q-jet carbs.
Rich
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Offline blazer74

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Ignition switched feed for choke?
« Reply #4 on: October 10, 2019, 02:14:41 AM »
I put the switch up behind the Alternator in the 1/8 port there on the block in my 74 K5
Ran a wire from an aux fuse panel I installed in the cab next to the factory fuse panel and is dedicated for the choke..
Wiper motor has an ignition hot wire that is accessible also.
« Last Edit: October 10, 2019, 11:21:20 AM by blazer74 »

Offline 75gmck25

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Re: Ignition switched feed for choke?
« Reply #5 on: October 10, 2019, 05:08:12 AM »
The wiring harness on my '75 had an ignition-switched brown wire exiting the loom near the brake booster, and it was used for a factory installed dual battery relay mounted on the driver's side fenderwell.  The relay and battery are long gone, so I extended the wire and used it for an electric choke.  I don't know if that extra wire is always installed, or if it was only there if you had dual batteries.

Bruce

Offline VileZambonie

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Re: Ignition switched feed for choke?
« Reply #6 on: October 10, 2019, 06:04:08 AM »
You do not want the choke to come on in the accessory position, only when the engine is running, which is why we use the oil pressure switch as an easy way to get that engine running signal. The port is on the driver's side of the distributor. Look over in that area for an existing switch and brass fitting. 1/8 NPT tee can be purchased at any hardware store or you can find tons of them on eBay if you don't want the hardware store look. I keep a bin or assorted 1/8"-NPT fittings, adapters and tee blocks for when I do swaps.
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