Quadrajet Dual accelerator pump

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Chris350

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Question on my 86 c10 with a 305. So i've purchased this truck about a month ago and i'm picking up where someone has left off. I've researched enough to figure out that the dual accelerator pump isn't totally necessary, but..... i'm left with a couple of questions. 1) is that related to or tied into the electronic spark controller in any way? 2) Do you leave it plugged in, or unplugged? i've read reasons for both. 3) Its to be hooked to the coolant temp sensor on the T-Stat housing to turn off after 160, that sensor isn't there and is plugged. What the problem with putting in a sensor and just let the system run? If i were to do that, is it the same sensor as the gauge? no one distinguishes the sensor by their locations when buying them. Yes i understand it would be simple to replace the carb entirely but my next year winter project is an engine swap to a 355 that i'm planning on building. So for this summer i just want to drive and enjoy it as is. Its running super rich right now and i'm doing a quick carb rebuild in the quadrajet. Thanks in advance
 

AuroraGirl

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Question on my 86 c10 with a 305. So i've purchased this truck about a month ago and i'm picking up where someone has left off. I've researched enough to figure out that the dual accelerator pump isn't totally necessary, but..... i'm left with a couple of questions. 1) is that related to or tied into the electronic spark controller in any way? 2) Do you leave it plugged in, or unplugged? i've read reasons for both. 3) Its to be hooked to the coolant temp sensor on the T-Stat housing to turn off after 160, that sensor isn't there and is plugged. What the problem with putting in a sensor and just let the system run? If i were to do that, is it the same sensor as the gauge? no one distinguishes the sensor by their locations when buying them. Yes i understand it would be simple to replace the carb entirely but my next year winter project is an engine swap to a 355 that i'm planning on building. So for this summer i just want to drive and enjoy it as is. Its running super rich right now and i'm doing a quick carb rebuild in the quadrajet. Thanks in advance
uh...

you have a 305 from 86 with a computer qjet ? thats not fully operational?

I would make the distributor normal non ESC and I would trade somoene for a regular qjet and then do that
 

fast 99

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Not too sure that you have. Never seen a 2-accelerator pump q-jet?
Feedback q-jets were common on cars but can't remember one on a truck. Trucks had a different emission requirement, more relaxed.

Provide a picture so we know what it is.
 

Octane

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Unless you're a "specialist"just get a Holley.
 

Ellie Niner

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No. The dual displacement accelerator pump is a standalone thing, and not tied into the ESC at all. You've already got half the circuit figured out; the temperature sensor actually supplies power to the circuit once you've reached 160 degrees, energizing the solenoid on the carburetor. This opens a valve inside the carb that diverts about half of the fuel in the accelerator pump well back into the float bowl when you step on the gas. Leaving the plug on the carb or temp sensor disconnected gives you the full squirt all the time.

FWIW- The temp sensor on mine has failed so that it's powering the circuit all the time. The engine doesn't seem to miss the extra fuel even when it's cold, so I've left it plugged in.

I'm pretty okay with Q-jets, which have worked well for me. The only issue I've had is with the airhorn warping around the carb-to-intake bolts. Whatever zinc/cream cheese metal they used tends to creep over time.
 

AuroraGirl

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No. The dual displacement accelerator pump is a standalone thing, and not tied into the ESC at all. You've already got half the circuit figured out; the temperature sensor actually supplies power to the circuit once you've reached 160 degrees, energizing the solenoid on the carburetor. This opens a valve inside the carb that diverts about half of the fuel in the accelerator pump well back into the float bowl when you step on the gas. Leaving the plug on the carb or temp sensor disconnected gives you the full squirt all the time.

FWIW- The temp sensor on mine has failed so that it's powering the circuit all the time. The engine doesn't seem to miss the extra fuel even when it's cold, so I've left it plugged in.

I'm pretty okay with Q-jets, which have worked well for me. The only issue I've had is with the airhorn warping around the carb-to-intake bolts. Whatever zinc/cream cheese metal they used tends to creep over time.
full squirt you say :bleh:
 

Ellie Niner

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full squirt you say :bleh:
Ayup. Full squirt always gets the job done!

I thought about gasket sealant, but came up short on stuff that I thought would pass muster. I carefully stuck the airhorn in a press and straightened it a little, then used a file to straighten it a little more. Still not 100% satisfied with it... do you have any sealants you'd recommend? Oh, and they're bolts.
 
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AuroraGirl

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Ayup. Full squirt always gets the job done!

I thought about gasket sealant, but came up short on stuff that I thought would pass muster. I carefully stuck the airhorn in a press and straightened it a little, then used a file to straighten it a little more. Still not 100% satisfied with it... do you have any sealants you'd recommend? Oh, and they're bolts.
I suppose the permatex removeable aviation stuff
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According to some google searches other people have sealed airhorns of carbs by using that per the instructions it works well but do you use gas with alcohol? it seems like its alcohol based but it can be diluted with it... but Im not sure what that means after cure and on a airhorn, gasket wise.
 

potent rodent

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iv got an 86 gmc with the 305 and had the same set up u have, as soon as i put in a diff dist and carb my fuel milage went down bad . if i were u i would leave it as is and drive it
 

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