Electric choke

[sjarrett71]

I saw a rerun of Trucks! and Stacy David said the best thing to do is run the electric choke through an oil pressure or temp switch. Has anyone done this or know how? I have an Edelbrock with an electric choke that wasn't hooked up when I got the truck but I want it to be. Right now I just hooked it to a switched ignition source. Is this safe or should I use the oil temp switch?

[69rut]

Mine is wired up from ignition source.

Don't see much difference from that and the oil pressure switch except that the pressure switch would be easier to jump off of.

[cdowns]

the oil pressure switch is a good idea // what it does is it gives a slight delay to the choke opening since the choke doesn't get power till the engine has oil pressure

[68speedalert]

I believe the reason for going thru the oil switch is to reduce a fire hazard.

IF you have a wreck, and fuel is laying/sprayinig everywhere, and the key is left on, voltage is going to the choke coil......it heats up more.... right next to a fuel source,..... and


POOFFFF!

With the oil switch, when the motor quits after an accident, even with the key on, there isn't any voltage going to the coil.

All OEM wired their electric chokes in a way that would have voltage only with the engine running.

I'm sure they recommended it on the program for "liability reasons".

[piecesparts]

Look for a plug in your block, just above your oil filter, if there is one, that is the spot GM chose for the oil pressure switch to be installed to control the choke in the mid eighties trucks. You will need to get a switch that is on at pressure and off when there is no pressure to make this work. Then run a 12 volt keyed ignition source to the pressure switched and then up to the choke.

If there is no plug, then you could tap off of the sending unit's connection on top of the motor, where the connection tree is already installed, but it gets crowded there.

My 84 GMC has the pressure switch, but my son's 86 is wired direct from the ignition source for his choke. It workes either way.

[68speedalert]

Originally Posted by piecesparts

Look for a plug in your block, just above your oil filter, if there is one, that is the spot GM chose for the oil pressure switch to be installed to control the choke in the mid eighties trucks. You will need to get a switch that is on at pressure and off when there is no pressure to make this work. Then run a 12 volt keyed ignition source to the pressure switched and then up to the choke.

If there is no plug, then you could tap off of the sending unit's connection on top of the motor, where the connection tree is already installed, but it gets crowded there.

My 84 GMC has the pressure switch, but my son's 86 is wired direct from the ignition source for his choke. It workes either way.

I don't think the original motor has that plug.

There isn't a tee by the dizzy either. If he has a gauge, it is mechanical and will need to find a tee that will work with that fitting. Probably just an 1/8 inch pipe thread.

If it's got an oil light, then it just takes getting a switch for the early 80's unit, like you described.

[sjarrett71]

My truck has a reman engine in it, not the original. I do have the original guage in the dash though. So basically I get an oil pressure switch, hook a switched ignition source up to one side and run a wire from the other side to the choke? I'm sorry I'm sounding stupid, but electrical stuff is not my bag, I just want to be safe.

[VetteVet]

http://www.google.com/search?hl=en&q...c+choke+wiring

I love google.

[68speedalert]

Yes that is correct. You could even just use the wire that is running to the choke now, just attach it to the switch.But.....you need to find that plug around the filter. It will be to the bell housing side, straight up from the filter mount, if it has the plug.

The other trick is to find the right switch. If you have a good NAPA store with an experienced counterman/manager, he should be able to look thru the books to find one.

OP6616 might work. It's listed for an 85 Chevy van g2500 w/5.0 ltr. I think that switch just worked the choke.

BTW, was just in Rolla last night visiting numberoneson at school. Was his b-day and wanted to take him out....

Steve

You'll have to tee it in the original line, like I said, if you can't find that plug. If the reman engine was your vintage block, it may not have it.

[sjarrett71]

Thanks VetteVet, I think I'll try that.

[sjarrett71]

68speedalert, I was on duty last night but wasn't out of the office much. Was typing all the accident reports I've been taking lately because of the weather. Hoe you had a good time. BTW, where'd you go?

[68speedalert]

Went to the Feed Lot. Last year it was the Ground Round and was happy with it. They had changed and we figured, WTH, let's give it a try.

It was good. Had a sweet gal for a waitress, but this must be her first gig as one.....she was clueless.

[sjarrett71]

Yeah, most everyone out of there has been arrested for one thing or another (most multiple times), even the manager. Next time you come to Rolla let me know, I'll try to recommend a place.

[68speedalert]

Alright.....starting to feel a little queasy............URP!!!!

[piecesparts]

Originally Posted by 68speedalert

I don't think the original motor has that plug.

There isn't a tee by the dizzy either. If he has a gauge, it is mechanical and will need to find a tee that will work with that fitting. Probably just an 1/8 inch pipe thread.

If it's got an oil light, then it just takes getting a switch for the early 80's unit, like you described.

Those oil pressure tree connections are a dime-a-dozen in the salvage yards, GM dealerships, and even Street and Performance sells them to let you upgrade to TPI unuits on older motors. They are the same pipe thread connection that the sending units are and the oil galley has a plug right beside the dizzy on even the older motors. At least every one that I have had. If nothing else use brass adapters and connect them in a "Y" effect off of the fitting.

Actually the choke will open without the pressure switch or electric power, it he switch only allows the electrical current to go to the choke unit to heat it to allow it to close (NOT OPEN). There is a bi-metallic spring in the choke housing that turns towards the choked position, when it is cold. There will be no delay to set the choke and once the motor is running, then it allows the heater to warm up the choke.

[68speedalert]

Originally Posted by piecesparts

Actually the choke will open without the pressure switch or electric power, it he switch only allows the electrical current to go to the choke unit to heat it to allow it to close (NOT OPEN). There is a bi-metallic spring in the choke housing that turns towards the choked position, when it is cold. There will be no delay to set the choke and once the motor is running, then it allows the heater to warm up the choke.

I either don't understand are you are a little off.

Correction....the choke will only open on it's own if.....it is heated with a choke tube. That is a tube running from the intake (or exhaust manifold on some other models) that runs to the choke housing. Vacuum from the carb pulls the heated air thru the housing, making the spring EXPAND, allowing the choke to open.

There is no way the current makes the choke close. Unless someone put the wrong choke coil on the engine you were checking. The Roch 2 bbls have their springs wound in the opposite direction as Qjets and they otherwise will interchange. If someone swapped them, your choke would close at it got voltage.

They don't make an electric conversion for the 2bbl carbs, so I took one from a Qjet, flipped the spring over and now my 2bbl has an electric heated choke.

[piecesparts]

Let's see what is up here, I did get the sentence above a little misconstrued in the comment about closing. That is what I get for reading all of these threads--messed up.

TRY THIS: We ARE talking about an electrically operated choke, correct. Then if you take a look at the choke housing (bakelite thing) it is the spring/heated bimetallic control. If the temp outside gets cold, the choke spring winds itself (tighter) in the forward direction (Especially on an Edelbrock/Carter designed AFB carb) to set the choke when you, the driver, pushes on the gas pedal. By doing that you released the choke assembly that is being held open by the screw on the throttle linkage. The choke is now closed and the high idle cam is set against the adjustment screw. The driver now starts the vehicle and due to the source for electricity being available, the heater unit in the housing starts to heat the coiled spring and it starts to expand and unwind in the reverse direction, in comparison to the front of the motor. After the preset amount of heating time the coil spring turns the choke back to an open position and the high idle cam drops away from the throttle linkage and the carb is back on it's normal idle screws for fuel/air mixture.

The use of a choke tube (older style engines) accomplished the same thing, but the direction the choke travels is relative to the carb that it is on. It is all the same, but the heat source is different.

[68speedalert]

Nicely done.

You DO know how it works!!!!

Hope I didn't offend ya!

Maybe one beer too many after supper last night?????

[piecesparts]

No I just type to fast and do a lot of other stuff at the same time. It is sickening; there are girls driving around --cell phone in hand, eating whatever, looking at the mirror putting on make up, and smnoking(I call this multitasking) and I get my sentences backwards.