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Old 04-16-2017, 08:07 PM   #1
56weav
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Another carb question

Hello Everyone,
Today while working on my 1986 gmc short bed with a 305 v8 at which I am trying to straighten out the previous owners modifications. I discovered the exhaust system has no o2 sensor. The Quadrajet carb does have the electric solenoid on the top no
throttle connection on the front. 1 wire on the solenoid is hooked up the other is not and it is just sitting on the intake. I am speculating ? this wire would go to the o2 sensor if it had one. Here is my question. I have a 800 cfm quadrajet with an electric choke that does not have any electrical hookups ,can I by pass the ecm computer and successful use that carb and not effect the distributor?
The truck actually runs pretty good after I removed the non operative smog and
Straighten up all the vacuum leaks of which there were many
Thank You
David
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Old 04-16-2017, 08:54 PM   #2
Alex V.
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Re: Another carb question

Are you sure the electrical device and wires are part of a feedback carb. or the high idle solenoid? I don't recall seeing any feedback Qjets used on Chevy trucks, if there even is such a thing.
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Old 04-16-2017, 09:26 PM   #3
Dead Parrot
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Re: Another carb question

Pics of distributor and carb will help. Sounds like is it likely that a PO has changed one or more parts.

Also, check your state's/city's rules on emissions inspections. Would suck to remove everything and get it working just to find out your next project is to put it all back.
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Old 04-16-2017, 09:55 PM   #4
56weav
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Re: Another carb question

It's always an adventure buying old vehicles that have been " worked on" it appears to be the original carb but I wouldn't bet my life on it. One thing about living in the middle of the corn and soybean country. What smog rules?
I'll shoot some pics tomorrow after work. Thank you stay tuned I'll be back in touch
My longer term objective will be to increase the hp on this 305 without spending a fortune
It appears it will be fairly reasonable to bring it up to the L69 specs on a mid 80s z28 / Monte Carlo SS
David
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Old 04-17-2017, 06:47 PM   #5
56weav
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Re: Another carb question

Good Evening
I went ahead and unhooked the connection to the carb while it was running.
It didn't change how the truck idled weather hooked up or unhooked. I did not drive the truck though.
The picture attached will show the carb the wire in question and the distributor.
The question is. Can I move to a quadrajet without the electrical hook up and achieve good engine performance and not effecting the distributor?
Thank you
David

I can't figure how to make the pictures display on the forums so I hope you won't mind checking out these image links:

http://imgur.com/6GohEF8
http://imgur.com/NLDce70

Last edited by 56weav; 04-17-2017 at 07:01 PM.
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Old 04-18-2017, 11:01 PM   #6
Damien
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Re: Another carb question

From what I can see the distributor has been changed to an older non-computer controlled unit. The computer controlled distributors will have another connector that runs to the firewall by the back of the passenger side valve cover. You should be able to swap carbs without issue.
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Old 04-19-2017, 07:51 AM   #7
56weav
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Re: Another carb question

Yes ,I agree I drove it all yesterday unhooked and it ran ok.
I think from what I could research the solenoid attaches to the senor in the thermostat housing and activates upon cold weather starts with more fuel .
The local GM dealer is a friend of mine he chuckles every time he seethe truck he claims his old carb man was an artist long ago retired
Too bad it thinks it's just a 2 barrel at the moment
Thank You for you response
David
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