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  •  » FYI Ford, Classic Mustang Tech Discussion
  •  » Stalling problem, no idle, performance cam and holley carb?

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    7/15/2013 9:00 PM  #1

    LondonSteve
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    From: London, Ontario, Canada
    Registered: 4/01/2013
    Posts: 136

    Stalling problem, no idle, performance cam and holley carb?

    I have a new to me 67 fastback that just developed a severe stalling problem, so bad I can't drive it.

    I drove it since early May for about 500 miles with no problems other than a bit balky when cold, but once warmed up for a couple minutes ran great, no problems. Now it will not idle at all, even in park and fully warmed up. As soon as you take your foot off the throttle it drops to almost zero rpms and stalls.

    Engine is a 302 V-8 from 1968. Rebuilt with "Hypereutechtic" 10-1 pistons, a 430 lift cam, balanced. Heads had a valve job with new seats, guides and valves. Intake is Offenhauser dual port aluminum. Carb is Holley 450 cfm Steet Avenger, with manual choke. Crane Flamethrower coil, Pertronix ignition conversion. Has factory 1.6 rockers in it with 4 barrel heads. There was a 2200 or 2400 rpm? stall converter and shift kit installed by previous owner.

    The only thing that has changed that I can think of is I cheaped out a bit on the last fill up and put half and half blend in instead of premium, but I am down to about a quarter tank and it ran fine up to this point. It still seems to be getting plenty of fuel. Looked closely and could not see any sign of a vacuum leak either.

    I am at a loss as to why it has gone to hell, from running well, with no changes made to the set up.  HELP!

    Thanks - Steve

     

    7/15/2013 9:12 PM  #2

    6sally6
    Hyper FYIFORD ADDICT

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    From: Surfside Beach,SC
    Registered: 4/02/2013
    Posts: 7,044

    Re: Stalling problem, no idle, performance cam and holley carb?

    Check the obvious stuff first.......plugs.....timing....air filter...
    Try getting some carb cleaner(or my favorite....Brakleen) and spray into carb while reving engine.
     Also try getting it running enough to control engine  by working carb by hand.  Rev it up pretty good and hold your hand over the top of carb and choke it down that way....almost! Keep it running and clamp hand over the carb several times. Hold the throttle wide open and clamp hand over the carb and just before it dies.....remove hand and then repeat a few times. This will suck "most" any trash that may have got through the filters.
    How old is the tank?!????
    6sally6

    Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
     

    7/16/2013 6:44 AM  #3

    LondonSteve
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    From: London, Ontario, Canada
    Registered: 4/01/2013
    Posts: 136

    Re: Stalling problem, no idle, performance cam and holley carb?

    Tank is new and pickup and filters are new. The car did sit in storage for close to two years and was only started once before I got it. However, it has performed perfectly for the last two months since being pulled from storage. Had lube oil and filter with cam conditioner done to it shortly after getting it on on the road.

       •Thread Starter
     

    7/16/2013 7:24 AM  #4

    MS
    Forum Originator

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    From: Canyon Lake, Texas
    Registered: 1/24/2013
    Posts: 12,782

    Re: Stalling problem, no idle, performance cam and holley carb?

    Your engine sounds like it has a sensible combination of parts that should produce crisp performance and good gas mileage.

    This definitely sounds like a fuel/carb or fuel pump issue to me.  Sitting for two years with the ethanol gasoline mixtures now in use may have precipitated some early problems with carb seals.  Even if it drove for a while, it may have done some damage to fuel lines, etc.

    Around the perimeter of the air horn, there are some air bleed holes.  Be sure those are clean. Some spray carb cleaner and tiny wires are best for doing so.

    Next, I would remove the needles and seats and clean them.  This is easy to do by simply unscrewing them from the top, at the same place the float level is set.  You might want to just buy new ones so you get new o-rings with them.  While the needle/seat assembly is out, spray the carb cleaner in there through the plastic tube that comes with the can of cleaner.  You will have to reset the float levels when you do this.  That carb has pressed-in fuel level sight plugs, so do not try to remove them.  They are not threaded like the old Holley plugs and if messed with, they can start to leak.  Use a flashlight and shine it on them and adjust the level until the gas is at midpoint or slightly below.  Level is adjusted by turning the needle/seat assembly.

    I bet getting those two items done will cure the problem.  If it doesn't, a replacement fuel pump is under $20.  If you have a diagnostic pressure gauge for the pump, you can check its output to determine if it is putting out enough pressure.

    Change one thing at a time.  I would not mess with timing or anything else until the carb or pump is eliminated as an issue.

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

    7/16/2013 2:00 PM  #5

    LondonSteve
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    From: London, Ontario, Canada
    Registered: 4/01/2013
    Posts: 136

    Re: Stalling problem, no idle, performance cam and holley carb?

    On closer examination and some research on the Holley tech site, ( I am new to Holleys ) , I discovered that both the idle mixture screws were missing. ( Just open threaded holes. ) I obtained replacements along with the cork plugs and intalled them to the one and a half turn starting point. Got the car running, and much improved with a further half turn out from this baseline, plus a slight increase to curb idle speed. Successfully drove it around the block and no stalling.

    I am going to follow the proceedures Mustang Steve described to clean it up and ensure there is no sticking in the needle and seat. ( The intake area of the carb is kind of black. )

    The guys at the speed shop where I got the idle screws from could not believe it would have run at all without them installed up to this point. Much less run well.  I can't understand it. The previous owner must have removed them, for maximum setting, and it ran fine. Maybe the drop in octane brought the problem to light.

    FYI - This one has brass screw in plugs, and not the clear sight plugs.

       •Thread Starter
     

    7/17/2013 3:32 PM  #6

    MS
    Forum Originator

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    From: Canyon Lake, Texas
    Registered: 1/24/2013
    Posts: 12,782

    Re: Stalling problem, no idle, performance cam and holley carb?

    Well, that is one I never would have thought to ask about.  Will keep it in mind for the next guy...

    Glad you got it running right.

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

     

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