Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

'85 Q-Jet power piston ???

Discussion in 'The Garage' started by jms, Sep 26, 2002.

  1. jms

    jms 1/2 ton status Author

    Joined:
    Jan 24, 2001
    Posts:
    1,683
    Likes Received:
    0
    Location:
    --
    \'85 Q-Jet power piston ???

    My carb is a M4ME with the dual accelerator pump setup. I may have finally diagnosed the cause of an overly rich condition that caused me all sorts of grief on the way to B'Bash and back (again, thanks to fisher1648, Storm Trooper, and BigBlue76 for your help to get it to run right): the plastic retainer on the power piston doesn't seat right, allowing the spring to push the piston too far up. Result is the piston is stuck in the up position, essentially pulling the primary metering rods out of the main jets all the time - so it's running rich all the time, and mileage is down the dumps, you guys don't want to see my fuel bill for B'Bash! /forums/images/icons/laugh.gif

    My question is: can the power piston be taken apart? Edelbrock sells the retainer, so I ordered it, together with power piston springs and a few different jets (cause I'd like to try and get a bit better mileage after I fix the power system). Of course, now, after looking at the piston, I'm not sure how to install the new retainer. The piston has a cross pin, but I'm not sure whether that's the secret to taking it apart so I can get the plastic retainer on the 'collar'. Roe's Q-Jet book is mute on this one, so if anyone has any info, it's greatly appreciated, thanks, michael.
     
  2. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    7,385
    Likes Received:
    0
    Location:
    Atlanta
    Re: \'85 Q-Jet power piston ???

    Uhhhhhhggggg Hate that version of the quad. I'd dump it and get one for about an 80. It will have all the correct connections for the Emissions. The only thing it wont have is that stupid solinoide that is forever screwing up. The other alterantive is to replace the solonoid and rebuild the carb.
     
  3. jms

    jms 1/2 ton status Author

    Joined:
    Jan 24, 2001
    Posts:
    1,683
    Likes Received:
    0
    Location:
    --
    Re: \'85 Q-Jet power piston ???

    Grim, it's not the carb where there is a solenoid to run the power piston system (I think that would be the E4ME). Its the version where there's only one solenoid on the pass. front side, with input from the temp sensor; the solenoid supplies fuel to help the accelerator pump while the engine is cold. The power piston itself is not controlled by a solenoid, but by vacuum.

    My Edelbrock goodies won't arrive until Tuesday anyway, maybe I'll try a junkyard around here to source another Q-jet.
     
  4. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    7,385
    Likes Received:
    0
    Location:
    Atlanta
    Re: \'85 Q-Jet power piston ???

    Yep that's the one I hate.
     

Share This Page