View Full Version : Backfiring carb


71Nova400
Sep 4th, 06, 02:41 AM
The initial start of my Nova is great. It's when I drive and stop somewhere for a short period of time, and try to start up the car. Sometimes it is fine and starts up like a champ, and other times it keeps cranking, stuggles, and doesn't turn over. Finally when I get it to start, it's idles rough, almost stalling, and I can hear the carb backfire, making that spitting noise from under the hood.

I was told that it could be my carb, or that the timing is off. The car runs great, idles smooth, pulls hard, and has no problems. I have a feeling that the timing is off, but can't check until I get a timing light. I'm hoping to get some input before I purchase a light (if I need it) , so that I can properly diagnose the problem and fix it.

Thanks

So-cal Jack

strtlegal
Sep 4th, 06, 04:14 AM
what type of coil are you using?? hei?? i ve been down this road before..about 5 years ago i had my motor running good then i would shut it off and restart it, it was looking like my timing was off, so i almost pulled the timing cover off to look at my timing marks but i thought i might try a friends hei and bigger than crap my damn mallory hei coil was the culprute..what a p.o.s.

just some help, but it does sound like a timing issue if it back fires..but some of the other things youve posted sounds like you might have a small carb issue

71Nova400
Sep 4th, 06, 03:23 PM
what type of coil are you using?? hei?? i ve been down this road before..about 5 years ago i had my running good then i shut it off and restart it, it was looking like my timing was off, so i almost pulled the timing cover off to look at my timing marks but i thought i might try a friends hei and bigger than crap my damn mallory hei coil was the culprute..what a p.o.s.

just some help, but it does sound like a timing issue if it back fires..but some of the other things youve posted sounds like you might have a small carb issue

Thank you for the advice. I am running a Pertronix distributor, with an Accel Super Stock ignition coil. How can I diagnose the coil to see if it's the problem?? I'm hoping it's something simple, so I won't have to tear into the carb.

thanks for the help

So-cal Jack

strtlegal
Sep 4th, 06, 08:16 PM
only real way i know is using a test unit or another off a buddies car..you could probably pick up a stock coil for next to nothing just to test yours..just an idea

71Nova400
Sep 7th, 06, 07:52 PM
Should the timing be at zero??...advanced, retarded??? Any input would be helpful.

Thanks

so-cal Jack

strtlegal
Sep 8th, 06, 01:21 AM
your initial timing i, i think , should be around 10-12 btdc..its a good area for typical street car..check this with your vaccuum advance disconnected

what kind of carb do you have?

71Nova400
Sep 8th, 06, 02:56 AM
Thank you for the advice. I have a Holley 750.

strtlegal
Sep 8th, 06, 02:58 PM
you maybe over carb'd. every motor varies so its hard to tell...my car somtimes is hard to start in hot weather..i thought it was vapor locking or dead heading but if i pump fuel in it it acts like its flooded but then starts..i think when its hot here the fuel in the bowls bubbles and either vaporizes or leaks out somewhere..carbs are a touchy thing

71Nova400
Sep 8th, 06, 09:31 PM
I just timed the engine, and so far it seems to be running great. Thank you for the advice. I hope that the timing was the issue, and not some other major problem.

So far, it runs great, and fires right up.

thanks


So-cal Jack

strtlegal
Sep 9th, 06, 02:07 AM
GOOD!!! glad to hear