Easier Starting 101 - Impala Tech
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post #1 of 5 (permalink) Old 07-20-2018, 03:07 PM Thread Starter
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Join Date: Jan 2018
Location: Greenville, SC
Posts: 286
 
Hello all,
1968
396/TH400

My car does not start very easily. At the first bump of the key, it fires right up but immediately dies. This is followed by holding the key and turning the engine over and over and usually pumping the gas pedal 1-2 times. This results in a very weak, sputtering start-up that will again die as often as not. Eventually I'm able to get her running and off I go.

I'd like to improve this.

Here is what I've done to the car since bringing it home:

-HEI conversion
-PowerMaster 100 amp alternator w/ one-wire set up
-New battery (Advanced Auto gold brand)
-New spark plugs and wires

Here is what was already on the car:

-Remanufactured Q-jet of indeterminate age

The car does not give me any trouble once it's running, so I think the fuel system is in good working order. I've also tested the battery and alternator even though they are new and they are performing as expected. With the air cleaner off, the choke appears to be working also. What can I do to improve start-ups? MSD Ignition box? Thanks for any replies.

1968 Impala SS
496 Stroker
T56 Conversion
3.73 Posi-Trac
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post #2 of 5 (permalink) Old 07-20-2018, 03:51 PM
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Next time before you crank it up or turn on the key. Pop the hood, and remove the air cleaner look down the primary and pump the gas pedal three times. Are you getting a good strong stream all three times?

If not the Welch plug in the bottom of your Rochester QuadraJet is leaking the gas out of the fuel bowl. If you have ever returned to the garage after you parked from a cruise and smelt gas that is the gas that is evaporating on the hot intake manifold as it leaks out of the carb.

Just putting in a new Welch plug on a rebuild won't fix this well documented issue. You have to drill and tap the hole; and then install a pipe plug with epoxy sealer to fix this problem.

If your fuel bowls are full of gas, then you have too much initial timing.

Big Dave
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post #3 of 5 (permalink) Old 07-20-2018, 07:19 PM Thread Starter
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Location: Greenville, SC
Posts: 286
 
Thanks Dave. Will take a look.

1968 Impala SS
496 Stroker
T56 Conversion
3.73 Posi-Trac
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post #4 of 5 (permalink) Old 07-20-2018, 11:09 PM
BA.
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Location: Miamisburg, Oh.
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I wasn't sure that 3 pumps would be enough but basically, I was thinking along the same lines as Dave...... Fuel-related, empty fuel bowl, maybe a bad/weak diaphragm or spring in the fuel pump.

HOW A NOVICE REBUILDS A 66 IMPALA CONVERTIBLE:
http://www.impalas.net/forums/blog.php?u=1432
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post #5 of 5 (permalink) Old 07-24-2018, 08:38 AM
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Join Date: Jan 2018
Location: Coopersville, MI
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Also could be the choke if it runs rough until it gets warm.
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