Vaccum hose removed- shouldn't I hear a hiss?
#1
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Car: 1986 Firebird
Engine: 2.8 V6
Transmission: 700R4
Vaccum hose removed- shouldn't I hear a hiss?
Okay, I snapped a hard plastic vacuum line a while ago, and replaced it with a rubber piece for the time being. It connected the TB vacuum lines to the lines by the EGR solenoid. It was a good connection to the TB, and a "poorly shoved on" connection by the EGR.
I noticed it fell off by the EGR system. I couldn't hear any vacuum hiss under the hood with the motor running. I also didn't feel any vacuum when I placed my finger over the hole.
Vacuum comes from the intake manifold, right? It doesn't come at all from the TB lines? How is this possible that I would have an open vacuum hose, but no "sucking" noise/feel? Think I have a leak elsewhere, or a clogged line?
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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
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I noticed it fell off by the EGR system. I couldn't hear any vacuum hiss under the hood with the motor running. I also didn't feel any vacuum when I placed my finger over the hole.
Vacuum comes from the intake manifold, right? It doesn't come at all from the TB lines? How is this possible that I would have an open vacuum hose, but no "sucking" noise/feel? Think I have a leak elsewhere, or a clogged line?
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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!
#2
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Car: 4
Engine: 6
Transmission: 5
Ported vacuum probably...
Not all vacuum connections are equal. For specialized connections, they will often drill a port into the throttle bore above where the throttle blades rest at idle; that way there's only vacuum available at conditions above idle. Vacuum advance for ditributors is like that. EGR usually is hooked up that way too, when it's not controlled by a solenoid.
Try opening the throttle a little and see if you get vacuum.
Vacuum sucks, doesn't it?
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"So many Mustangs, so little time..."
Not all vacuum connections are equal. For specialized connections, they will often drill a port into the throttle bore above where the throttle blades rest at idle; that way there's only vacuum available at conditions above idle. Vacuum advance for ditributors is like that. EGR usually is hooked up that way too, when it's not controlled by a solenoid.
Try opening the throttle a little and see if you get vacuum.
Vacuum sucks, doesn't it?
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"So many Mustangs, so little time..."
#3
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if its the vac. port im thinking of, your car shouldnt idle (as well) at least with it open. or, mine doesnt. is it clogged maby inside? i havent the foggiest of how it would be, but engines do very strange things sometimes... so does the idle change when its open/shut? or maby i dont undersand quite right...
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Car: yep
Engine: uhuh
Transmission: sure does
I'm with RB83L69 on this one.
Should be ported vac. to the EGR solenoid.
Should have vac. off idle.
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ASE Mechanic/Machinist/Smog Tech
1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R
GO #3
Should be ported vac. to the EGR solenoid.
Should have vac. off idle.
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ASE Mechanic/Machinist/Smog Tech
1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R
GO #3
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Car: 1986 Firebird
Engine: 2.8 V6
Transmission: 700R4
Thanks guys! (Well, except for that pun, RB! ) I'll give that a try (raise idle, look for vacuum). I picked up a set of vacuum lines out of a junkyard, and even managed to copy the emissions label so now I have a vacuum line diagram.
I still don't believe my Helms book has no vacuum diagrams in it! Can't I buy that underhood emissions label from the dealer?
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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!
I still don't believe my Helms book has no vacuum diagrams in it! Can't I buy that underhood emissions label from the dealer?
------------------
-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!
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