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Yub350 10-18-2004 09:09 AM

engine trouble
when i hit the gas pedal when stopped, i hear a pop in the engine and the engine wants to die. About 2 seconds later it kicks on again and i can start driving. Its a 77 chevy 350. Any idea to the problem?

killerformula 10-18-2004 09:39 AM

couple of things, could be too much or too little fuel, probably from something out of tune or worn. Try throwing it in neutral when it does that and rapping it up. Black smoke come out the exhaust? If so, too much fuel.

Your accelerator pump could be worn, supplying too little fuel. Do you have to pump the car a bunch of times to get it started? Generally too much gas will flood your motor causing bog, this is also an option. What kind of carb do you have, a Qjunk? jk, I actually like qjets.

Those year motors were notorius for having cam problems. Popping back through the carb is a possible sign of a bad cam. Is this the original equipment in this motor?

Vacuum leaks can cause the problems you're talking about. Get out your carb cleaner and check for that first.

Lastly, be sure your timing is good to go. Too much initial or worn springs that are advancing too quickly can also cause what you described. It really should have nothing to do with vacuum advance (I've found most people have no idea what vacuum advance does or how/when it works) given that if you're doing a WOT run, even off a stop, your vacuum should be 0. If its not, something is wrong.

Best of luck, hope that's helpful-


poncho62 10-18-2004 09:43 AM

I agree..............especially the vacuum part...cracked hoses etc.

I thought that Chevies cam problems didn't start until 78, although I could be mistaken.....

Yub350 10-18-2004 09:45 AM

Its a rebuilt motor. New cam, intake, carb. All vacuum lines are hooked up. I think the motor only does it when I just started it. It goes away when warmed up. Timing could be the problem, what should the timing be for a 77 350?

poncho62 10-18-2004 09:47 AM

When cold, there may be a vacuum leak under the carb, which seals up with the heat of the engine........

Ghetto Jet 10-18-2004 09:52 AM


Originally posted by Yub350
Its a rebuilt motor. New cam, intake, carb. All vacuum lines are hooked up. I think the motor only does it when I just started it. It goes away when warmed up.
My car does that too.

It's cold. Let it warm up.

Yub350 10-18-2004 09:57 AM

I noticed it was doing it at every stop light i was at today. I already warm it up for 5 mins in the morning and the problem still insists. Every time it happens theres a loud click from the engine. Could it be a misfire?

killerformula 10-18-2004 11:34 AM

its probably a pre-ignition.


USA1 10-18-2004 05:48 PM

Would pre-ignition make it want to die? Almost sounds like a lean sneeze to me. Vacuum leak or timing or possibly even valves too tight. Check accelerator pumps for adequate spray.

Yub350 10-19-2004 08:32 AM

Do you think re-jetting my carb would help? I moved the choke housing to alittle more lean also, could that be the problem?

USA1 10-19-2004 08:45 AM

Set your choke when it is absolutely cold, before starting. THat could be your whole problem.

Yub350 10-19-2004 08:55 AM

I thought the choke flap has to be all the way open though, thats why i turned the choke housing.

USA1 10-19-2004 09:05 AM

When your motor is cold, first thing in morning, set the choke plate where it is just closed. Too much pressure and it will run rich, not enough and it will run lean. Set the flap where it just touches cold.

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