Click on image for the lowdown. 
====
| | |
2 members (gswbbc, Gray_Ghost),
50
guests, and
2
robots. | | Key: Admin,
Global Mod,
Mod | | | Forums66 Topics128,035 Posts1,055,446 Members48,422 | | Most Online14,466
Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down
with Ads!  Again, thanks!
| | | | Joined: Feb 2004 Posts: 29,750 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,750 | The choke applies itself with a bimetal spring anytime the temperature cools down. No electric input is necessary for that to happen. The electric part comes in for releasing the choke, usually within one minute of run time in warm weather or a max of 3 minutes in sub-freezing temps. If the engine stalls with ignition or accessory voltage applied to the choke, it continues to heat and release, and makes a restart difficult. I like to run the choke release voltage through an oil pressure sensing switch, so the choke heating only happens while the engine is actually running and the switch has oil pressure applied to it.
Try using a 3-terminal oil pressure switch from a mid-1970's Chevy Vega tapped into the same oil gallery that supplies the oil pressure gauge. Connect the voltage from the fuse block you pictured to one of the normally-open terminals, with the other N.O. terminal connected to the choke. A 10 amp fuse should be plenty to operate the choke heater. Oil pressure will close those contacts and heat the choke coil while the engine is running. Either leave the normally-closed contact with nothing connected to it, or use it to ground an idiot light to supplement your oil pressure gauge.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | Jimmi, The oil pressure switch is threaded and screws into the T-fitting that screws into the block. The T-fitting has one male end (into the block) and two female ends (one for the pressure switch and one for oil line to oil filter). Here is an oil pressure switch that works on my electric chokes: https://www.napaonline.com/Catalog/CatalogItemDetail.aspx?A=MPEOP6626SB_0213427398&An=0 | | | | | Joined: Aug 2010 Posts: 368 Shop Shark | | Shop Shark Joined: Aug 2010 Posts: 368 | Tim: Why did you use this setup vs. a wire dirict to Ign. pole on Ign. switch? Langdons says to wire dirict...Just looking at all options.
Thanks | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 |
Jimmi,
Are you asking "why" use the oil pressure switch (HrL explains that, above).
Or, are you asking about where to obtain a hot lead to run to the oil pressure switch (I did not want to run a wire from under the dash, through the firewall)?
| | | | | Joined: Feb 2004 Posts: 29,750 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,750 | Langdon's is wrong- - - - -it's that simple.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Aug 2010 Posts: 368 Shop Shark | | Shop Shark Joined: Aug 2010 Posts: 368 | Thanks Guys: I will catch power from my fuse box,run it to my
" tee'd " Oil Pressure switch. then run a wire from switch to Electric choke... Done....
Any special guage wire ? | | | | | Joined: Feb 2004 Posts: 29,750 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,750 | 16 gauge ought to be plenty. It's a fairly low-current circuit. There's a nickel/chrome heater coil wound into the choke housing that provides enough heat to help the choke release itself quickly.
The first electric-heated chokes were used by Ford in the 1980's, and they ran a 16 gauge wire from the alternator stator winding to heat the choke housing. That one only produced power with the engine running, which accomplished the same result as using an oil pressure switch. It would be difficult to tap off a GM alternator that way, and just about impossible to do that with a DC generator.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Aug 2010 Posts: 368 Shop Shark | | Shop Shark Joined: Aug 2010 Posts: 368 | | | |
|
|
