electric choke connection without oil pressure switch

[MikeB]

On an 82 C10 with electric choke, GM designed the circuitry so the choke does not get 12 volts (to heat it) until the engine is running and there is enough oil pressure to close the oil pressure switch and complete the circuit to the choke heater.

My 1982 schematics show a light blue wire running from the oil pressure switch to the choke heater. The 12 volt feed wire to the switch appears to be pink/white. I'm trying to determine if I can simply connect the light blue wire to the pink/white wire and bypass my non-existent oil pressure switch. I don't really car if that disables the oil lamp, because I have an aftermarket oil pressure gauge below the dash that will use separate wiring (outside of the harness).

If anyone has the answer to my question, I will be pleasantly shocked.

 

[foamypirate]

On an 82 C10 with electric choke, GM designed the circuitry so the choke does not get 12 volts (to heat it) until the engine is running and there is enough oil pressure to close the oil pressure switch and complete the circuit to the choke heater.

My 1982 schematics show a light blue wire running from the oil pressure switch to the choke heater. The 12 volt feed wire to the switch appears to be pink/white. I'm trying to determine if I can simply connect the light blue wire to the pink/white wire and bypass my non-existent oil pressure switch. I don't really car if that disables the oil lamp, because I have an aftermarket oil pressure gauge below the dash that will use separate wiring (outside of the harness).

If anyone has the answer to my question, I will be pleasantly shocked.

I don't see why you couldn't do that, if the pink/white wire is ignition switched. Though, GM designed it that way so the choke heater doesn't come on unless the engine is running. You might get weird choke behavior if you turn the key to ignition on/engine off before starting the truck when it's cold.

 

[GTME94]

I currently have the choke oil pressure switch bypassed like you mentioned. (I have the oil pressure gauge sender and a mechanical gauge connected to the engine and haven't had a chance to get another T to hook up the choke switch).

The choke still works ok, I'm just careful to not turn the key on in cold weather until I'm ready to crank and if it doesn't crank I turn it off until ready to crank again. The choke doesn't turn off that quickly with the power applied. It worked fine in Michigan with extremely cold weather but I don't daily drive it in cold weather.

 

[bucket]

I run my choke heaters straight to an IGN source too, daily driving in the winter works just fine. Not sure why there would be any reason for leaving the ignition on for an extended amount of time before cranking?

 

[77 K20]

I have my choke wired up to a switched ignition source. I found I liked it better. For example this last weekend I drove up a very steep road to a mountain lookout. The electric choke has a tenancy to cool off quickly even when the engine is at operating temp but turned off. If I just turn it on quickly it is set to a high idle for 30 seconds or so.
The last thing I need was a high idle when going down a very steep hill, so I turn the key on first, then fiddle around with seatbelt/map things like that, then start the truck.

 

[MikeB]

Thanks for the comments, guys. I ended up connecting the Holley choke to the pink/white wire (.8 PNK/WHT - 350) that goes the the fuse labeled "choke". This is the wire that is normally connected to the pressure switch.

Turns out there's some resistance in the circuit that feeds the fuse, because with a 13.8V supply, the choke gets only ~8 volts initially, and then the number gradually rises as the bi-metal strip heats up. Anyway, it works just fine.

On another note, I ended up running the alternator wires out of the harness by the starter, and then along the oil pan rail and up the front of the engine. Used cushioned wire clamps at two pan bolts and at the top front motor mount bolt hole. Looks really clean. Will post pictures when I terminate the wires.

 

[MadOgre]

Thanks for the comments, guys. I ended up connecting the Holley choke to the pink/white wire (.8 PNK/WHT - 350) that goes the the fuse labeled "choke". This is the wire that is normally connected to the pressure switch.

Turns out there's some resistance in the circuit that feeds the fuse, because with a 13.8V supply, the choke gets only ~8 volts initially, and then the number gradually rises as the bi-metal strip heats up. Anyway, it works just fine.

On another note, I ended up running the alternator wires out of the harness by the starter, and then along the oil pan rail and up the front of the engine. Used cushioned wire clamps at two pan bolts and at the top front motor mount bolt hole. Looks really clean. Will post pictures when I terminate the wires.

My Eddy carb is wired that way too. It was originally a diesel so I didn't have the factory choke wiring.


My 83 K20 has the factory wiring exactly the same as you just did yours and it looks good IMO. I think I will be keeping mine that way too.

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