80 Camaro bogs down with any throttle

Discussion in 'Troubleshooting & Diagnosis' started by 80'Maro305, Jul 14, 2017.

  1. 80'Maro305

    80'Maro305 New Member

    Nov 22, 2014
    Concord, NH
    1980 Camaro, with the 305, will run at idle but will bog down when press on gas. When full throttle is applied slowly, it will stay running initially, but will bog way down to very rough idle. It makes this sucking sound like it is starving for air. Also, when the car is in gear and driving it will stall unexpectedly.

    I've rebuilt the 4bbl, tested for compression, retimed it correctly, taken the intake manifold off and resealed it, plugged all vacuum lines not in use, checked fuel pump pressure. The fuel tank, lines and fuel pump are 1-2 years old. Electric choke is ok and initial timing is set to 6 degrees BTDC. Still have PCV valve and snorkel. Smog pump, EGR valve, and most of other emissions stuff was removed. Carb is
    1980 Rochester Quadrajet 4MV Number: 17080202. Seems to be the original when the car was produced.

    When I put away last fall it was running perfectly. It was parked under a barn but with no heat. I'm at a loss.

    [​IMG] [​IMG]
  2. 80sz

    80sz Veteran Member

    Feb 2, 2014
    Are the weights moving in dist? Check to see if they froze up
  3. Bandit723

    Bandit723 Veteran Member

    Oct 1, 2016
    Waupaca WI
    Have you checked the fuel filters?
  4. budro6968

    budro6968 Veteran Member

    Apr 2, 2016
    Jax Florida
    When you rebuilt the carb did you take out the power valve assembly? I had a situation that showed up a couple years after a rebuild of a 40 + yr old Q-Jet. The ring that retains the power valve popped out and the valve was not seated properly. The engine would idle perfect but would die on light to moderate acceleration. I could also rev it and open the secondaries. Of course this happened on the road some 20 miles from my house. I didn't know it at the time what the problem was. I dicked around and could drive a few hundred feet and die. Made it home and took the carb apart. and found the problem. The retainer is not part of the rebuild kit so this thing was probably rebuilt 5 times since I had it. You have to stake the ring in place. The the ring was no good it was crumbly. I could not find one either. I ended up getting a Carb from summit and just bolted it on and no problems since. I called summit and asked if they could get the part I needed. They said no. I asked how do you rebuild your carbs then? They said they get their carbs from Carb Specialists. I called and spoke with a guy named Greg. He said they sell that part. I never did get it though since my new carb is doing fine. There is also another Carb place called Cliff's performance. Might try to give either one a call. There are other things like trash blocking jets that could be the trouble. Hard to say without taking it apart. Good luck...
  5. rchydzik

    rchydzik Veteran Member Lifetime Gold Member

    Nov 13, 1999
    Colbert, WA USA
    Probably not related, but what is your distributor vacuum advance connected to? Check that your timing is advancing with RPM as mentioned above and rule out any ignition problems.

    Really dumb question, but is the fuel filter installed in the correct direction? I only ask because I did it myself once.
  6. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

    Feb 26, 2004
    Bloomington, MN
    This might not be related to this issue but I would put your accelerator pump rod in the front hole. (See arrow in pic)
    This will give a bigger shot of fuel when you step on the peddle and open the carb to sucking air.
    (There's a little lag in fuel delivery as the moving air pulls fuel from the bowl, the accelerator pump is there to fill the fuel delivery gap with a squirt of gas.)


    Free moving distributor weights are definitely worth checking.
    Timing... I would shoot for 12-14* BTDC. (Vacuum advance disconnected and vacuum line plugged.)
    The 4-6* recommended by factory is primarily to meet emissions standards.
    (I can tell by looking at the top of the distributor and its alignment with the firewall that it's a bit retarded.)

    Budro has a good point about a possible internal carb issue too.
    We didn't see what you did there so that's kind of hard to diagnose.

    Good Luck!
  7. dave@ztech

    dave@ztech Veteran Member Lifetime Gold Member

    Mar 27, 2016
    if it was running perfect when you put it away and now its running like this, I agree with Bandit723, check the bronze filter at the carb, and any inline ones, seams like it is not getting the fuel,
  8. Layne02

    Layne02 Member

    Jun 25, 2013
    Have you put a vacuum gauge on it? They can help at least pinpoint where the problem is. Just make sure to plug into full manifold vacuum.
  9. 80'Maro305

    80'Maro305 New Member

    Nov 22, 2014
    Concord, NH
    80sz was right! Distributor weights froze up/springs went bad. I replaced the distributor with exception for cap and rotor. Of course that was after I had torn the carb apart again, replaced the fuel filter, adjusted the APT and idle mixture, punched out the cap on the APT and tapped it so I can get to it later. I also adjusted timing to 12 degrees and that helped. So thanks Twisted_Metal. Now I've just got to fine tune and replace cap and rotor. Thanks everybody.
  10. 80sz

    80sz Veteran Member

    Feb 2, 2014
    Nice! Back to cruising

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