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Old 05-04-2010, 10:06 AM   #1
Jobe72
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Need help diagnosing bad start up issues...

I've had my 72 GMC for about 2 months now. 350/350 combo all original engine and rebuilt trans. Here is the issue I'm having...

Generally when I go to first start it up it cranks right over with a flip of the key regardless if it's cold or warm. But over the last two weeks it's been sputtering and stalling on me on the first start up of the day once I try to get going. Idles just fine, but when you get on the gas it acts up. At first it would go away after a few little spurts, but now it will stall at least once and be really hard to start back up...then once the truck warms up a little it's just fine.

Now I know the valve guides/seals are worn pretty good, it smokes at start up every morning but I haven't noticed smoke after that at all. I'm going to replace the carb with a Road Demon soon while I rebuild or have the Q-jet rebuilt. I've checked the choke and it seems to operating just fine.
Would the oil drain back from the bad valves cause this? Seems like a fuel issue to me, but why would it get better once it's warmed up?

Any help would be great...I've already sold my late model and my caddy is up with bad brakes! This is my daily driver!

Thanks.
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Old 05-04-2010, 10:48 AM   #2
cdowns
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Re: Need help diagnosing bad start up issues...

sound like youneed a tuneup
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Old 05-04-2010, 11:03 AM   #3
Jobe72
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Re: Need help diagnosing bad start up issues...

HEI, plugs and wires are all less than a year old, new air, oil and fuel filters.

I think it's a fuel starving issue...

Once it's going it runs like a champ.
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Last edited by Jobe72; 05-04-2010 at 11:04 AM.
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Old 05-04-2010, 02:16 PM   #4
cdowns
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Re: Need help diagnosing bad start up issues...

have you ever check the tank for crap in the tank clogging the in tank strainer
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Old 05-04-2010, 02:45 PM   #5
Jobe72
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Re: Need help diagnosing bad start up issues...

Brand new tank as well. I would think if it was junk in the lines then I would have that problem all the time...been there done that with my 62 caddy!

Can the q-jets fuel bowls leak into the intake manifold? I'm thinking now that maybe my fuel is draining out and the fuel pump is trying to refill it so I'm starving for fuel at start up or when ever it sits for awhile.
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