Help! starting problem

[A1Avette79]

I have a 79, L48, automatic with a/c. Very basic car. I just had the carb (Quadrajet - stock) rebuilt. Also replaced the spark plugs, spark plug wires and ingintion coil (replaced with a Accel HEI). The starter is new (high output) and the alternator is fairly new (6 months). The car has great power now and runs nice and smooth.
The problem I am having is the car is really hard to start if it has sat for more than a couple hours. Not just the first start of the day (I live in S. Fla so cold weather is not an issue) even in the middle of the day if the car has been sitting for a while it will be hard to start. This didn't begin until the carb was rebuilt. Before I had the carb done the car didn't have much upper end power and it ran rough so the carb was definitely in need of a rebuild. But it did always start pretty easily.
I press the gas pedal twice before starting to set the choke. When I turn the key to start the car it will almost catch once and then die. Then I will have to crank the starter for between 5 - 20 seconds before it starts. Sometimes even then it won't start and I'll have to turn the key off for a couple seconds and then crank it again for 5 - 10 seconds before it catches. When it is hard to start like that it will run rough for the first 5 minutes or so and then it "warms up" and runs great. Other times it will stumble on the first try but by pumping the gas it will catch and if I keep playing with the gas pedal it will stay on.
The mechanic who rebuilt the carb has a lot of experience with vettes and quadrajets so I trust that he did a good job on the carb. He has adjusted the choke twice since he rebuilt the carb to try to correct the starting issue. I am going to take it back for a third adjustment but I wanted to run this through the Action Center first and see if anybody had any ideas. Like I said above before the carb was rebuilt the car started pretty easily.
It sounds like a choke issue to me. I guess it could be a fuel pump problem but what are the chances of the fuel pump going bad at exactly the same time the carb was rebuilt!
Any comments would be appreciated.
:confused

 

[Vettehead Mikey]

Sure sounds like the choke to me.

 

[damoroso]

Sounds like the choke or choke pull off might not be adjusted right. You wouldn't have to be out of adjustment much in FL to make it hard to start..

 

[A1Avette79]

Thanks, I hope you're both right. I would rather it be a choke adjustment than some kind of fuel issue!

 

[gmjunkie]

Thanks, I hope you're both right. I would rather it be a choke adjustment than some kind of fuel issue!

I hope it is too!!
But if it isn't,you'll need to remove the carburetor and check the lead plugs in the bottom of the float bowel!!Q-Jets are bad to leak over time,even more prone after a good soak in carburetor cleaner!!

 

[A1Avette79]

Would that be something that the mechanic who did my carb rebuild would have checked when he reassembled the carb? If the plugs leak where does the fuel leak to? This sounds like a fire hazard!

 

[LVMYVT76]

It leaks down into the intake manifold, and if that valve is open, down into the cylinder wall, going past the rings and into the oil in the pan. Not a good thing to have happen. You can pull your dip stick out and smell it, if it smells like fuel, it is leaking down.

 

[A1Avette79]

OK, none of that sounds good. Luckily, I just picked up the car from the shop and it seems to be starting better. It still wants to die a little after the first start but I know vettes are cold natured. I'll drive it for a while and see how it goes.
I should have had the shop install a new choke thermostat spring while they were at it. Its the original spring as far as I can tell from the maintenance records so it will go at some point. If I put in a new spring myself will that throw the choke adjustment off?

 

[fm1]

I press the gas pedal twice before starting to set the choke.

Press the pedal once to set the choke. Depressing it the second time is squirting an excess amount of raw gas into a choked carb and is just shy of flooding. This should help.

 

[jeffn]

Press the pedal once to set the choke. Depressing it the second time is squirting an excess amount of raw gas into a choked carb and is just shy of flooding. This should help.
Press the pedal once with the key on, or before turning the key ? I'm having somewhat of the same problem and am going to get my quad rebuilt this winter.When she's warm, she goes.Starting can sometimes be a pita.If it dosen't start with the first attempt , I floor it and she fires up .After a little pedal play it's ok...Other times, no problem at all.

 

[fm1]

Once before you turn the key on.
Mine fires right up in about 2 seconds of cranking with a little tap of the gas. However the Vette does only have 16k original miles on it. I also have an '84 Monte SS that starts the exact same way, and that has 110K miles on it.

 

[jeffn]

Once before you turn the key on.
Mine fires right up in about 2 seconds of cranking with a little tap of the gas. However the Vette does only have 16k original miles on it. I also have an '84 Monte SS that starts the exact same way, and that has 110K miles on it.

I'll try that tomorrow after I fix the choke tube hose. On close inspection, there is a slit down 1/2 of the length of the hose..The vacuum must be being compromised to the choke because of the bad hose..The hose is only about an inch and 1/2 long but the loss of vacuum to the choke must have some affect on starting , don't you think? 42K miles on mine.

 

[Vette79]

Time to switch to an electric choke...

 

[jeffn]

Time to switch to an electric choke...

But it is sooo much fun sorting this stuff out......When I get the carb rebuilt over the winter, I'll ask the master...He will set it up perfectly and I will ask about the electric choke. Until then, I'll fiddle with it and see if I can tweak it a bit.....Heck....There is enough summer left around here. Maybe I'll just get it done now.

 

[Vettehead Mikey]

An electric choke is not the answer, they don't work better or worse than mechanical, just differently. I haven't touched my mechanical choke in almost 20 years since it was last set up properly.

Setting it up properly is the key.

 

[jeffn]

An electric choke is not the answer, they don't work better or worse than mechanical, just differently. I haven't touched my mechanical choke in almost 20 years since it was last set up properly.

Setting it up properly is the key.

The answer is.....I changed out the choke tube hose on BOTH ends of the choke tube(which was fine) and adjusted the lean/rich on the choke to 1 mark lean (from almost all lean,God knows how it got all the way there).
With 1 mash of the pedal and 3 cranks of the starter , she fired right up.The fast idle works fine, so once the oil pressure built up and the fast idle was off, response in the pedal was instantaneous and strong.....When starting it hot, it fires up with like 3/4 of a starter crank......I'll take it out today and see how it goes but right now I think the problem is solved!..:cool

 

[fm1]

Problem solved. Enjoy your summer crusing !

 

[jeffn]

Problem solved. Enjoy your summer crusing !

After further beating, this bad boy runs like new...When warm it starts instantly with no pedal.When cold, 1 pedal mash and then 2 or 3 cranks and she fires right up...A complete pleasure to drive again.....Thanks all !