Choke question

[wm69]

New Jeeper

Just got my 2150 mounted and now need to see if I can get the choke working. I know most people here like the manual choke but I'd like to try the electric choke first and if I can't get it to work I'll try the manual out. The BBD that was on the jeep had a manual choke rigged up on it. The wire on a BBD or even weber electric choke is the same I'll hook onto the 2150, so where do I hook the wire coming off the electric choke that came on the motorcraft carb? Maybe if someone could tell me what color the wire is going to their choke or trace it back to wherever it terminates. I've got a birdnest of wires so the possiblities are endless if I try the guessing game.
Thanks!

 

[lah2420]

If I remember right, my choke wire is brown. As far as tracing it, I wouldn't even begin to want to trace it through all the wiring. I'd probably knock something else loose with my luck.

 

[Inspector-Gadget]

Hi-Ya wm69,

I am working from a fogged memory on this one, but…

Look at the wires on the engine oil pressure-sending unit on the rearmost passenger side of the 258 engine. The wire that supplies electrical power to the carb auto choke runs first from a key-on-hot source of 12 Volts through an oil pressure activated (oil pressure closed) electrical switch and then to the carburetor electric choke.

Power to the carb auto choke coil is routed through the oil pressure sending unit switch to prevent premature choke pull-off. That is, 12 Volts is applied to the auto choke mechanism only when the engine is running and producing enough oil pressure to close the oil pressure sending unit electrical switch.

A wire from the oil pressure-sending unit should be visible coming out of a wire loom behind and near to the carb.

If there is more than one unconnected wire behind the carb, use a test light or a voltmeter to determine which of those wires is “hot” only when the engine is running.

I will determine the wire color-coding later today.

Hope that helps for now,

Regards,

Gadget

 

[lah2420]

For all you "photo-choppers"

I know this wasn't my post, but I wondered what that oil pressure switch was for. My Haynes book doesn't even show it. I'll have to look myself and trace those out to put in the book for future reference.

 

[Inspector-Gadget]

RE: Re: RE: Someone upstairs has a strange sense of humor

Hi again, wm69,

Re: The Automatic Choke Wiring.

First, my apology: It took longer to get back to this than I anticipated – Christmas craziness going on here.

The wires going to the automatic choke on my 1985, CJ-7, 258, are red with white tracers. Actually, it is two wires of that color scheme. The electrical spade lug that slips onto the auto choke tab serves also to connect the two red w/white tracer wires. One of those two red/white wires goes to the oil pressure sending unit.

While I had time today, I also confirmed the voltage application scheme. With the ignition key “on,” but engine not running, zero-Volts were measured at the automatic choke. When the engine was started, 14.4-Volts (cold engine, high idle, at the time) was applied to the automatic choke electrical connection.

I hope that helps.

lah2420 -- When I initially replied to wm69’s question, I first read his sig line. His Jeep and mine are the same model year and identically equipped, so I replied to wm69 in that context.

I did not mean to imply that ALL model years of 258 engined Jeeps are so wired. I do not know that to be the case.

Regards,

Gadget