Rebuilt CCC Qjet Tuning

Discussion in 'Engine Topic' started by MP81, Oct 8, 2019.

  1. MP81

    MP81 Veteran Member

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    If I ditch the CCC carb, I'll also need to change the distributor, since this one has electronic advance. I'd just like to make it all work, as it should, for the time being, especially since I took the time to rebuild the thing. I'm an engineer, so making things work as they should has always been of great interest to me.

    The carb actually was plenty clean when I took it apart - nothing gummed up at all.

    It seems to run fine, it's just that it won't give me a dwell reading. I haven't taken it out for a drive since the rebuild, which was last fall, though.

    There's a specific troubleshooting section in the Service Manual for "Dwell fixed below 10*" which I am likely to follow and see. Where is the computer actually located?
     
  2. Rustbucket350

    Rustbucket350 Veteran Member

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    You need to pull that distributor out, swap that carb and tune that motor like it should be running. I am also an engineer. The more simple any mechanical thing is the more reliable it is. Therefore, it is less likely to break and it should perform to its function. It will take an afternoon to swap in an HEI non computer controlled distributor and a non computer controlled Q Jet. Take the o2 out and weld the hole up or cut the harness off the o2 and leave the o2 as a plug in the exhaust.
     
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  3. MP81

    MP81 Veteran Member

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    Oh, if I end up going that far, it's going EFI.
     
  4. Rustbucket350

    Rustbucket350 Veteran Member

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    If you follow the harness off the motor you'll find the computer. If you have an 81 or possibly an 80 California emissions model the computer should be in the console from what I've read.
     
  5. Rustbucket350

    Rustbucket350 Veteran Member

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    Thats your choice and I won't disagree but thats a way more difficult change than a non computer carb
     
  6. Rustbucket350

    Rustbucket350 Veteran Member

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    You could spend 100 bucks on a used intake, 100 on a used holley, and 60 for a distributor and be done. It'll crank all day long with one turn of the key and a pump of the gas.
     
  7. bourbon_scotch

    bourbon_scotch Veteran Member Lifetime Gold Member

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    dwell..... dwell..... dwell..... doesn't ring a bell anymore
     
  8. MP81

    MP81 Veteran Member

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    While I appreciate all the suggestions to change the setup, that's not my intention at the moment, so if we could try and steer the topic back to troubleshooting this specific issue, I think that would be best.

    It seems like the car is going into closed loop - there's a distinct point where RPMs change in an instant (the sticking high-idle cam is a separate issue, which I think mostly comes from the car sitting since October - normally I start the cars on a monthly basis, but never did that this winter), and then if I try and choke the engine by covering the choke horn, the engine takes a second or two, but clearly changes to attempt to stay running. Removing my hand causes the opposite effect - a second or two after and it reverts to normal running. If the car was in open loop, it should just stall out, no?

    But that said, if it's in closed loop, I should be getting a varying dwell reading, since obviously it needs to tell the MCS to add/remove fuel. But if it's not - what is the jump in RPM?

    This is quite the conundrum. Another thing I saw online is that perhaps, due to having long tubes, the O2 sensor isn't warming up enough just sitting at idle?
     
    Last edited: Apr 5, 2020
  9. MP81

    MP81 Veteran Member

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    It looks entirely factory, and based on the wiring schematic, it probably is, but what is the purpose of the secondary connector on only one of the O2's wires (I cannot say if it is tan or purple...because both wires appear to be tan), prior to the actual 2-pin O2 connector? It covered with what I expect is original factory tape (because it was rock solid and chipped/flaked/broke off, rather than actually unraveling).
     
  10. bourbon_scotch

    bourbon_scotch Veteran Member Lifetime Gold Member

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    it goes to ground

    you've been on this since october?

    .
     
    Last edited: Apr 5, 2020

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