Voltage drop on electric choke.

[swilliams]

Sorry more of my electrical ignorance. The hot wire going to my choke with the key on is 12.3 volts.



When I hook it up to the choke and check again (key on) the volts drop to 3.6. Should this happen.



Voltage is usually better I just had the key on for a while.

[bd]

That depends on how the choke stat is wired.  Does the choke hot wire run through an oil pressure switch and do you have a functional "Choke" warning light in the cluster?

[swilliams]

The light is functional it stays on all the time unless I unplug the hot wire to the choke.  I have not traced the wire directly to the oil pressure switch. I know that I have started having problems with the choke cold start and I was trying to trace the problem.

[bd]

With the ignition switched on, check the voltage on both sides of the Choke fuse.  If the fuse is blown, replace it.  If the fuse is good, with the ignition on and engine not running, probe the pink/white wire at the 2-prong oil pressure switch. 

If the pink/white wire at the switch measures 12 volts, replace the OP switch (or the switch connector, as needed). 

If measured voltage on the pnk/wht wire at the OP switch is low, repair the pnk/wht wire and/or its connection through the firewall bulkhead plug.

[swilliams]

On my oil pressure switch it only has this one wire. Orange, Brown, Pink I am not sure. With the key on not running 8.76 volts.

[swilliams]

The wiring diagram shows a tan 5 wire(solid line) coming foo of the Oil Pressure Sender, and pink/white, dark blue, light blue (dotted lines) going to the Oil Pressure Switch. I don't really know what this means.

[bd]

Dashed lines in a wiring diagram mean that the circuit wasn't used in all applications.  But, since your truck has a choke light in the dash, it came wired with the OPS circuit.

The single-wire OPS you imaged is for the dash oil pressure gauge.

The switch you're looking for (see below) has one light blue, one dark blue and one pink/white wires connected to the two prongs of the switch and is located adjacent to the distributor behind the intake manifold (or sometimes in the left side of the block just above the engine oil filter).  Powering the choke stat through the dashboard choke light (if that's what is occurring) w/o the benefit of the 2-prong OPS will not properly power and heat the choke.

In the case of factory wiring, the OPS powers the choke stat with 12 volts from the choke fuse when the engine is running, while simultaneously turning off the choke light in the dashboard.  If you are missing the OPS, you'll either need to add it and properly connect the factory wiring, or eliminate the choke warning light.  I prefer to power an electric choke through an OPS, so the choke doesn't heat and open just because I have the ignition switched on whether or not the engine is actually running.

[swilliams]

I finally got the time to work on it. Had to pull the dist. (to make it easier) Voltage to connection at pink and white wire is good. Replaced the OPS and the fuse now it works again. Thanks for the help.

[bd]

Anytime.