question about quadrajet vacuum ports / evac
#1
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Joined: Feb 2004
Posts: 100
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From: NJ
Car: 84 Z28
Engine: 305 HO
Transmission: 700r4
question about quadrajet vacuum ports / evac
My evap system was all hacked up by the last owner of my car, so im trying to get it back together. It no longer has a quadrajet, but now a road demon. my question is, when looking at the diagram that i'll post, the lines get routed into the ports that are labeled L, T, and H. I need to know if those are ported vacuum or just regular vacuum ports so I can hook this stuff back up. The tvs is still in the manifold, and I have the control valve. It looks like the line comes from the tank, to the pressure control valve (that possibly gets full vacuum because its in line with the pcv which gets full vacuum) then from the can to the tvs (does it matter if its the top or bottom port? my guess is no) then from that to the bottom of the control valve which is labeled can/tvs. The next port up on the can c valve says carb/bowl which goes to the T port on the quardrajet, so where would that go on a demon? The next port up says pcv, so i guess full vac on that, connected to the pcv, and tank control valve, and then the top of the canister control valve is says VAC, so i guess full time vacuum on that going to the H port on the carb. Basically I just need to know what the ports are on the quad. full time or ported vacuum... Thanks and hopefully this will help some others
#2
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Joined: Mar 2000
Posts: 43,169
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
H is a bowl vent, which doesn't exist on the Demon. All of that line can be plugged.
I think you can eliminate the big control valve and go directly to the TVS from a timed port.
Basically what you'll be providing is a fuel tank vent & canister purge.
I think you can eliminate the big control valve and go directly to the TVS from a timed port.
Basically what you'll be providing is a fuel tank vent & canister purge.
#3
Thread Starter
Member
Joined: Feb 2004
Posts: 100
Likes: 0
From: NJ
Car: 84 Z28
Engine: 305 HO
Transmission: 700r4
So, I can eliminate the canister control valve.... I put full manifold vacuum on the tank pressure control valve, then run the output of the canister into the tvs, and out of that into a ported vacuum source. Sounds clean enough hopefully will work... Does this all sound correct? Thanks for the help.
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