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Quadrajet help..please!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by jekbrown, Jul 9, 2001.

  1. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    I have a factory Quadrajet that came on my '85 Jimmy when it had a 305. When I had a new 350 installed...the mechanic guy told me I oughta get a new carb, since the Q-Jet was running "a little lean". questions:

    1) Isn't there any way I can rebuild the Q-Jet that would help? The thing is 16 years old, and as far as I know has never been rebuilt. =\ From what I understand, Q-Jets rock for off-road carbs...and if at all possible, I'd rather stick with my stock one (with rebuilding) rather than buy a new one, or convert to another type of carb.

    2) If there is no way it will work even with a rebuild....

    according to Chilton,

    "These 4-bbl carbs feature an electrically operated mixture control solenoid and are designed as part of the GM Computer Command Control (C3) system."

    ...thing is, when I look up replacements on, say, Edelbrock's www site, they all say "not for computer controled systems". Grrrr! Does anyone make a good replacement?

    3) If not, is it possible/legal/cheap to convert to a non-computer controlled system?

    Lastly: I know edelbrock etc make rebuild kits...with one of them and a chilton can any joe-schmoe rebuild his own carb? I wouldn't mind taking it to a pro to tune/calibrate everything once I install it, but I'd rather not pay mad ca$h per hour for the guy to rebuild it if I can do it myself.

    Anyway, there is a big 4x4 event I wanna go to soon...any info at all would be GREATLY appreciated. Thanks much!!!

    J
     
  2. POWERMAD

    POWERMAD 1/2 ton status

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    First it helps if ya fill out your profile.
    Depending on where ya are at you can swap the carb for an earlier model.
    and you will have to swap out the distributor to by-pass the ESC.
    I believe there is a way to by-pass it on that distributor but I will have to go searching for that info.
    For me swaping the carb and distrubutor was the easy way out and it ran great.

    my truck's not dirty, it's earth tone paint
     
  3. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    I believe all you have to do to richen up even the mix control models is change the main jets and metering rods.
    $20-30 in parts. I would still dump that carb and get the 1904. THe 1904 will bolt up and run all your current emmisions BS but does not have the mix. will plug and play with your electric choke wiring.
    You probably do not have a CCC Model carb. Those would have a TPS sensor (don't confuse this with the AC throttle kicker) on the throttle arm and a O2 sensor. We have not confirmed those were ever put on trucks. Nobody has ever shown up with one as far as I know. If they were it was only the Cali models. The cars like caprices got them and V8 and V6 gutlesses. You do have a mixcontroler. It is regulated by a temperature deal in the water neck. It has no ECM or use a O2 sensor to control mixture.

    It's not my damn planet monkey boy!
    <A target="_blank" HREF=http://communities.msn.com/OffroadK5s>http://communities.msn.com/OffroadK5s</A>

    Grim-Reaper
     
  4. slider79blazer

    slider79blazer 1/2 ton status

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    you should be able to rebuild it. the mixture screws probably have factory plugs still in just drill the plugs out . I have a Q-jet on mine 79K5 with a 400c.i. in it.

    <font color=purple>whats a 4 letter word for farm wagon?</font color=purple> (ford) [​IMG]
     
  5. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    I am not a carb guru by any means, but just looking at the exploded drawings of the thing in the Chilton...it sure looks like I have the TPS...

    I have some digital cam pics...since you are kinda a guru, could I email you one of them so you could take a quick look and settle things once and for all? ;)

    If so, do you have broadband, or should I minimize the res/size of the pic(s)?

    J
     
  6. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Well what makes it the CCC is the TPS. That's the potentiometer on the throttle linkage. If you got that it's a CCC If you don't have it then it is just the mix control model.
    I'm not saying it's impossible that you have one I'm just say I personaly have not seen one on a GM truck or ran across anybody that has one here. If it is a CCC carb and it's running lean then the ECU should bring up the mixture.
    Haynes shows it in their book also. They say the 85 I nailed my crate motor from should have it but it didn't The carb was not a CCC. It was just the mix control model. No computer on the thing.
    Your more then welcome to mail me the pic. OffroadK5@MSN.com I'll see if I can identify it. A straght on shot from the top and would be the best with air cleaner off the TPS should be clearly visible if it's a CCC.


    It's not my damn planet monkey boy!
    <A target="_blank" HREF=http://communities.msn.com/OffroadK5s>http://communities.msn.com/OffroadK5s</A>

    Grim-Reaper
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    Drivers side electrical plug=TPS. Passenger side plug=Mix control solenoid. I have confirmed ONLY the Mix control variants on the trucks. No TPS. All cars (GM) starting in 1981 up got CCC carbs and distributor.

    Just as easy to rebuild as the earlier variants. Pretty stupid idea if you ask me, to have a mix control solenoid not operated by the computer, but Gm must have done it for a reason. Probably upped mileage by a bit. (IE lower emissions) you wouldn't be doing the world a disservice by putting on an earlier carb, just save yourself some hassle, and get a Q-jet with electronic choke. Rebuild kits at chain auto stores are about $20. FWIW, they are glorified gasket kits, not rebuild kits ; )

    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
     

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