86 C10 and Edelbrock 1406 Electric Choke Help

[lucid]

Hi all,

Background:
My father has a 1986 C10 Pickup that originally came with a 305, and the OP ripped out the ECM and electronic stuff. When my dad bought it, it came with a 350 out of a Caprice (hydraulic flat tappet), an older Qjet and vacuum advance. When he got deployed, the Qjet went bad. I didn't know anything about Qjets, so I bought an Edelbrock 1406 and put that on. He rebuilt the engine in 2006ish, and we put in a Summit cam with .427" lift. The truck recently sat for almost 2 years and I just replaced the Edelbrock 1406 with a rebuilt unit, a new fuel pump, a clear wix fuel filter and blew air through the fuel lines.

Choke:
The factory blue wire going to the choke is there, and I have found the Oil Pressure Sender can with a single tan colored wire going to it. The choke light comes on but does not go off, and there is 0 voltage going to the blue wire at the choke heater. The 20 amp fuse at the fuse block marked CHOKE is good. I found a diagram in a Haynes manual stating there is an Oil Pressure Switch as well and it is connected to another fuse. I guess that the oil pressure sender turns on and grounds both the switch and the choke circuit? The diagram is kind of confusing.

Does anyone have a picture of where the Oil Pressure Switch is located? Any tips on wiring the choke any other way? I have the choke plate almost all the way closed but since the choke isn't getting powered it stays on the fast idle screw and idles pretty high to keep it running. I would like to run it with the factory wires if possible, but I could always add a relay of some sort because it seems the choke pulls a lot of amps when it's running.

 

[gmachinz]

It is above the oil filter pad, threaded into a pressurized oil galley. There should be a dark blue and a pink w/blk stripe from your bulkhead connector to this switch-pink is +12V IGN and the dark blue is for your choke light. At the connector, dark blue is joined with the light blue going to your choke-the path is now complete with key on and your light should go out. The single wire (tan) is for your gauge only.

 

[MikeB]

It is above the oil filter pad, threaded into a pressurized oil galley. There should be a dark blue and a pink w/blk stripe from your bulkhead connector to this switch-pink is +12V IGN and the dark blue is for your choke light. At the connector, dark blue is joined with the light blue going to your choke-the path is now complete with key on and your light should go out. The single wire (tan) is for your gauge only.

Exactly. It takes oil pressure for the choke to get 12 volts. Kind of clever, because if for some reason the ignition is left on for a while, the choke will get 12 volts and open with the engine still cold.

My truck's choke gets 12 volts anytime the ignition is on. Just last month I was having some problems getting it to start and idle in 20 degree weather. To complicate matters, I left the ignition key in the ON position between attempts at starting. So, the cold start/idle problem was further complicated by an open choke! Gotta get myself an oil pressure switch someday. Or maybe EFI.

 

[lucid]

I don't see anything plugged into the boss above the oil filter. It looks empty. The sender is plugged into an adapter. I was going to buy a T-adapter and screw both the sender and the oil pressure switch into it but I can't find it anywhere. Also, I cannot seem to find the connector for the oil pressure switch.

I also was looking for a GM fuse tap/ignition cavity connector for the fuse block and no one seems to sell them anymore.

On the passenger side, I found what looks like to be the HEI distributor connector, the knock sensor plug and maybe EGR solenoid? Not sure about the connectors on the drivers side. Anyone have pictures of their setup?

I think I am going to buy a oil pressure switch and try to find the wires that go to it.

 

[lucid]

Well, my dad and I traced the wire and I found it twisted behind the distributor and lo and behold, a connector! It looks like it originally had a T-junction and the mechanic just put in a single sender so the gauge would work, and hid the connector way in the back.

I read 12v across the connector with the key on, so it looks like it's still in circuit and working. I jumped the two leads with a jumper wire and turned the key on and the choke plate is opening now. The choke light isn't on anymore. Eventually, I am going to go to the junkyard and try to find that t-junction and add an oil pressure switch to make it work like factory. Even though I think they should have just left the electronic stuff connected, at least they didn't cut any wires off.

 

[gmachinz]

There ya go! With the average age of these trucks, you just never know what kind of shenanigans previous owners have done lol