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#1
11-15-2012, 10:02 PM
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'77 carb on a '72 car--mods required?
I just bought a 1977 rochester quadrajet off of a trans am with an electric style choke, and it's going on my '72 lemans. For the electric style choke, does anybody have any idea how to wire that up to a car that originally didn't have one even as an option?
I've only ever played with the divorced style choke before, so when it comes to the electric one, I'm kinda clueless. Also, will the carb or intake need any kind of modifications for vacuum, fuel or linkages to work with the older car? The car has a brand new reproduction harness for the engine and dash for a '72 GTO with gauges, A/C, v8 and an automatic, so I've got a lot to work with if I need to modify wiring.
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proud owner of a 71 Grand Prix and a 72 8-seater LeMans, currently in the body shop while I start the 467/4 speed build |
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#2
11-16-2012, 01:07 AM
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i think you can grab a 12v source for the choke at the wiper motor.
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#3
11-16-2012, 01:16 AM
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Bolting up to the intake should be the same, there might be some minor linkage differences, but they should be minor.
The choke wire simply wiring to a 12V hot source, as F Rock stated. The wiper motor would be a good place to start. Use a test light and find a 12V hot lead that is hot without the key on.
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LEAD, FOLLOW, OR GET THE HE!! OUT OF THE WAY!!! HONEST JERRY'S SPEED AND EQUIPMENT
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#4
11-16-2012, 08:20 AM
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The 1977 Pontiac carburetor was a "hot air" choke model, not electric. The electric choke was added at some point.
Make sure the vacuum supply to the housing was blocked. Do NOT use a gasket under the electric choke, they are designed to ground on the housing. The need a single 12v keyed "on" supply source, as mentioned, the wiper motor is a good location. The electric choke should "clock" with the terminal down towards the intake, and have a mark on it that lines up with the marks on the choke housing. Set it in the middle of the range to start with, and adjust if/as needed. It should be fully unloaded in apprx 3 minutes after start-up.....Cliff
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If you can read this, thank a teacher. If you can read this in English, thank a Veteran! https://cliffshighperformance.com/ 73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile), |
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#5
11-16-2012, 07:42 PM
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the choke on the carb is electric according to the pics, so I know I'm set there, unless the pics don't represent the actual item. I'll know monday when it gets here.
I shouldn't have a problem with finding a 12V source, I'll take a look at the wiper motor wiring seeing as how that seems to be the general consensus for the best choice. Does the choke only need power when the key is in the "on" position, or should it have power at all times?
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proud owner of a 71 Grand Prix and a 72 8-seater LeMans, currently in the body shop while I start the 467/4 speed build |
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#6
11-16-2012, 07:49 PM
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It has to be connected to a source that is hot only when the key is on, since obviously, you can't have it on a constant power source or it would be operating all the time.
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Steve F. |
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#7
11-16-2012, 08:12 PM
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ok, cool. Now, will the choke being wired into the wiper's power supply affect wiper operation or choke operation with the wipers running?
__________________
proud owner of a 71 Grand Prix and a 72 8-seater LeMans, currently in the body shop while I start the 467/4 speed build |
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#8
11-16-2012, 08:45 PM
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Given any choice, I'd route the power through an oil-pressure switch.
Key in "Cranking" position--NO choke power. Ignition "on", Running--Choke is powered. Ignition "on", Stalled--NO choke power. |
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