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Qjet question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Doug, Oct 10, 2001.

  1. Doug

    Doug Registered Member

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    I've got an '85 w/350. Gradual acceleration is fine, but if I floor it, it doesn't do much. The idle is okay, but not great. I haven't made my way yet to pick up a Qjet book. Not sure exactly what it is, but there is a white/clear piece (looking from front and down) on the front left corner on top w/ two wires on top, and two wires in front. The two wires in front are not connected. One wire could be reconnected, the other is broke close to the white/clear piece.

    '85 k5, 350, 700r4, np208, 10 bolts, as of 10/2001; wish list is extensive.
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Mix control solenoid. Likely runs full rich (on the primaries) with the wires disconnected. I'd hook it back up. Emissions and mileage can't be good with primaries at WOT.

    Check choke to make sure that when the vehicle is hot, it is fully open, and that the secondaries are able to operate.

    Accelerator pump as well could be the problem, you can either let it get cold, then press the plunger (which is the tip of the accelerator pump) on the top, front drivers side of the carb, down, and check for a strong squirt of gas, or you can try depressing the plunger with the vehicle running..should notice the idle change.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</a>
    No anti-theft measures on your truck? No pity when its stolen
     
  3. Doug

    Doug Registered Member

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    Why does mine have 4 wires? I've seen several at the local Pull-n-save last weekend, and they all had just 2 wires.

    '85 k5, 350, 700r4, np208, 10 bolts, as of 10/2001; wish list is extensive.
     
  4. Burbinator

    Burbinator 1/2 ton status

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    "Rochester Carburetors" by Doug Roe is by far, hands down the best Q-Jet reference to date that I've seen. My Naval Fleet
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, on par with that whole day yesterday, apparently your carb is full CCC. My guess is its not off of a truck. Check out the site in my signature (below) and check the quadrajet tech info. Decode what the carb year is. I'd bet thats off a car. We went through this earlier, I believe the '85 should at most, have just one plug. Yours has TPS and MC solenoid, so I'd guess its a car carb. 4 wires is odd though, I thought 5 should have been the total.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</a>
    No anti-theft measures on your truck? No pity when its stolen
     
  6. Doug

    Doug Registered Member

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    I don't know if it makes a difference, but the truck has California emissions on it. I'll check it out better this weekend and fill you in more.

    '85 k5, 350, 700r4, np208, 10 bolts, as of 10/2001; wish list is extensive.
     
  7. steve85fla

    steve85fla Registered Member

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    I have an '85 too, carb is electronically controlled. I would say hook it up right, or what I did was go to an older non-electronic q-jet, runs better now
     
  8. Doug

    Doug Registered Member

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    I'm not wanting to butcher the thing, I just want it to run well. I need to get a mixture control selenoid, because mine has one wire broken right at the selenoid, and the mate is just disconnected. the two wires on top are fine. There also two vacuum lines that I can not figure where they go. There are no open ports that I can see. I've capped them for now. Dorian, I'll look the thing over better this weekend when I have more time. I will get the number off of it before I head to work though. Would it be easier and/or cheaper to just get an older non computer controlled Qjet? It looks like a jungle under my hood with vacuum lines, wires, and all of the smog pump stuff. In the end, like I said before, I just want the thing to run well and get acceptable gas mileage.

    '85 k5, 350, 700r4, np208, 10 bolts, as of 10/2001; wish list is extensive.
     
  9. Doug

    Doug Registered Member

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    If it helps, the numbers off the carb are 17086057 and under that is 1086 JPR.

    '85 k5, 350, 700r4, np208, 10 bolts, as of 10/2001; wish list is extensive.
     
  10. Doug

    Doug Registered Member

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    The mixture control selenoid for my current carb sells for $120 from NAPA. When I was at the pull-n-save, all I saw was the two wire selenoids, and of course, the non computer controlled carbs. My question is, what vehicles and years should I look for, for a non computer controlled Qjet? Does it matter, were some better than others, any experienced info would be appreciated.

    '85 K5, 350, 700r4, np208, 10 bolts, as of 10/2001; wish list is extensive.
     
  11. Ddragggon

    Ddragggon 1/2 ton status

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    each Q-jet was tuned to a specific application to get the most perfrmance, emissions, and gas mileage out of them possible, for the engine, and vehicle combination. for this reason, a Qjet off of a 73 caprice with a 454 may not work well at all on a 85 chevy pickup with a 305 and 700R4. your best bet is to try and find a carbureator off of a truck that has the same GVWR, tonnage, engine, and if possible, transmission, and rear end gear setup. computer controls didn;t start until the 80's, and I'm not entirely sure exactlywhen, but all 4 of my trucks had non-computer controlled Q-jets on them, all of them 73's, and 77's. if you really want to get technical, you can change your metering rods, and control jets in the carbureator, and balance it out until you reach perfect acceleration, with optimal gas mileage. on the 73-87 Chevy trucks bulliten board, a guy with a 454 in a crewcab tuned his to get around 17-19 MPG, ( he's in canada, and his gallons are a quart bigger I think) and posted a very technical article on how he did it. I'll look through the archives, and see if I can find that post.

    my 77C20 running a 454/400 gets 13MPG regardless of how fast, how loaded, how much I tow, and what kind of hills I hit. my 77C20 pickup running350/sm465 got 16 MPG when I was a good boy, and 12 when I drove like hell on wheels. my 73 K20 hasn't had a through MPG test since I got it yet, so I don't have numbers on it.

    -Rich

    My truck isn't ugly, you have a skewed sense of beauty

    <font color=blue>2007 Ford XLS++ intrepid Ram Superduty 7000 R-type's suck</font color=blue>
     
  12. Doug

    Doug Registered Member

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    Another question...is there a way to tell if a peticular vehicle was setup to run at altitude? I live at about 5000 ft. (Colorado), but this doesn't necessarily mean all vehicles in the junkyards are all setup for high elevation.

    '85 K5, 350, 700r4, np208, 10 bolts, as of 10/2001; wish list is extensive.
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    Did some more research in my book. Apparently, in '85/'86, all you could get was A)normal, no electric Q-jet B) a "dual capacity pump" equipped q-jet, (one plug on passenger side of the carb) or C) a FULL CCC Q-jet, with two plugs, one on each side.

    First off, no clue what the "dual capacity pump" is. It is NOT an electric mix control ala the CCC system, as the primaries are still rods/jets that are spring/vacuum governed.

    All of the previous "altitude" Q-jets I have seen (exactly 1) have a large spring/plunger assembly in the aneroid cavity (passenger side, under the big "bubble" looking thing) Thats an altitude compensation device. No external clues to that one, had to get it apart to tell.

    80 was the first year of CCC in CA, '81 the rest of the US. Every car was CCC then (at least GM V6/V8 gas) but trucks, depending on application apparently, could have anything, up to '86 is my guess. 454's probably had plain Q-jets up until '86, while the 305/35o's could be either. My '83 305, Federal emissions, was not CCC.



    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</a>
    No anti-theft measures on your truck? No pity when its stolen
     
  14. Ressurection

    Ressurection 1/2 ton status

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    Check your throttle rods (the heavy guage "wire" that the butterfly valves mount on). If they wiggle around in their holes they need to be re-bushed. I used to get alot of spitting and sputtering when I'd punch it, and a friend pointed out that too much air flows in thru those ports. They go thru the base plate of the carb. Once I had that done, the problem went away completely.

    "High compression engines take longer to start!"
     
  15. Doug

    Doug Registered Member

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    Thanks, I will probably go the non computer route. I just don't want to dump $120+ for the selenoid, plus who knows what else when I can go to a non computer version cheaper. I would like to go to fuel injection, but that can wait for a while longer. I just need to get my hands on the book by Doug Roe and begin tinkering. If you have anymore suggestions, or ideas for me, feel free. Especially leaning toward high altitude mods and tuning. I just want this thing to run well and get respectable mileage.

    '85 K5, 350, 700r4, np208, 10 bolts, as of 10/2001; wish list is extensive.
     
  16. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    If yours is CCC controled and you go to a none CCC controlled carb. You will need to change the dist. also. It is also controlled by the computer.. I just went that route. It is temp. for me. I am going TBI in dec...Dan

    If it ain't broke.......Don't fix it....
    <a target="_blank" href=http://coloradok5.com/gallery/Gokartergo>KLICK</a>
     

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