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Vac hoses on q-jet correct?choke pullof hookuP? pg2

Discussion in 'The Garage' started by broncoman6524, Mar 5, 2007.

  1. broncoman6524

    broncoman6524 1/2 ton status

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    basically is this correct? the pcv sucks ALOT of vacuum...like you unplug it and teh motor starts to stall...
    [​IMG]

    the bottom vac hose is to pcv...

    thanks guys. i feel 110% for posting this LOL
     
    Last edited: Mar 18, 2007
  2. FightinTXag

    FightinTXag 1/2 ton status

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    Looks right with no EGR and such. The PCV causes a monstrous vacuum leak. My truck won't run below 2500rpm or so if it's unplugged.

    I assume the vacuum hose running from the throttle side and looping out of the picture is running to your vacuum advance. If so, I believe that's correct (ported).

    Choke pulloff / secondary lockout is hooked up somewhere in the back right?

    I'd pull off that chintzy piece of hose with the screw in it and get a real vacuum cap for the port under the choke.

    Are you having problems?
     
  3. broncoman6524

    broncoman6524 1/2 ton status

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    no i just swapped form the edelbrock to the q-jet. just makin sure its ok.

    choke pulloff...the only vacuum hoooked to it is what is shown besides the braake booster thingy which screws into the back.
     
  4. FightinTXag

    FightinTXag 1/2 ton status

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    The thing circled in red is your choke pulloff.
    [​IMG]
    It is intended to crack the choke butterfly open about 1/8" once the truck fires up and is idling with good vacuum. Of course as the truck warms the electric coil expands inside the choke opening it the rest of the way.

    The other function it serves is to prevent the butterflies on the secondaries from opening until there is no vacuum (ie wide open throttle) for a couple seconds (enough time for the diaphragm to relax after vacuum is removed). Lack of this thing can cause the WOT bog similar to too loose of a secondary butterfly spring.

    Of course it only works when it's hooked up to a manifold vacuum source, and the linkages are adjusted correctly, and the diaphragm is not torn.

    Mine had a torn diaphragm, which caused a vacuum leak. So I got a replacement at Autozone when I rebuilt my Qjet. My truck actually has two of those pots. I've got one in the rear like yours that controls the secondaries opening, and one in the front that cracks the choke plate open. But different GM applications used just the front one or just the rear one or both to control those two functions.
     
  5. TexasBlazerBoy

    TexasBlazerBoy 1/2 ton status

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    Hijack on:

    Does doing that with your fuel filter help?:confused:

    Hijack done
     
  6. TexasBlazerBoy

    TexasBlazerBoy 1/2 ton status

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    ttt
     
  7. FightinTXag

    FightinTXag 1/2 ton status

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    You mean the extra inline fuel filter he added? Couldn't hurt.
     
  8. TexasBlazerBoy

    TexasBlazerBoy 1/2 ton status

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    So what is the point of the mod? Does it increase fuel flow? I already have the rubber line mod:doah:. I wrenched to hard when trying to replace the fuel filter.:o
     
  9. FightinTXag

    FightinTXag 1/2 ton status

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    It's just another fuel filter, helping insure that the fuel is clean. Plus you can see through it and tell if it's getting gunked up. That's not true of the OEM filter.
     
  10. GotLabs

    GotLabs 1/2 ton status GMOTM Winner

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    The Qjet filter is about half length of a AA battery. The inlines are easier to swap also.
     
  11. broncoman6524

    broncoman6524 1/2 ton status

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    huh such as around 4grand? it feels like a misfire until you let off just a TINY bit and it fixes itself?
     
  12. TexasBlazerBoy

    TexasBlazerBoy 1/2 ton status

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    So, do I still need to keep the fuel filter inside the carb, the stock one?
     
  13. FightinTXag

    FightinTXag 1/2 ton status

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    Yeah, that could be a symptom. I guess the choke pulloff isn't hooked up on your truck?
    I would.
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    No, you don't have to.

    Not interjecting personal opinion here, run one or the other. The stock one leaves something to be desired, as it IS fairly small, and will bypass completely once it plugs up.

    Maybe that's good, maybe that's bad, but splicing the lines in that area is increasing the chance of a catastrophic fire. Don't say it can't happen, it has, and it will continue. There's a reason GM did not use rubber line there, and it wasn't cost effectiveness.
     
  15. TexasBlazerBoy

    TexasBlazerBoy 1/2 ton status

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    That has been my concern(fire). I bought a pre-bent line from LMC and it did not work. So I am stuck with the rubber line. Me and benders don't work well together:doah:
     
  16. GotLabs

    GotLabs 1/2 ton status GMOTM Winner

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    Very good point. My line was kinked so it made since to add the filter there. I am going to change it out and put it at the frame point where there is a rubber line.
     
  17. vortec

    vortec 1/2 ton status

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    i run 2 filters just like that one. one is before the pump, one after. i do not have the stock filter, anymore. in your location, while fire is possible, my first concern would be vapor lock, from engine heat. but, if yours works right, then :thumb:cool.

    do you have pics from other angles? i want a clean appearance like that, on my 82 350 with q-jet.
     
  18. broncoman6524

    broncoman6524 1/2 ton status

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    yeah ill get more pics tonight.
     
  19. broncoman6524

    broncoman6524 1/2 ton status

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    its hooked up but only from a nipple on the assy right back into the carb...is that right?
     
  20. FightinTXag

    FightinTXag 1/2 ton status

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    I assume you're asking about the choke pulloff thing I circled in red on the first page of this thread. If so, then yes, that's right.
     

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