CRG Discussion Forum

Camaro Research Group Discussion => Maintenance => Topic started by: camaro jock on June 26, 2014, 05:10:11 PM

Title: Help in diagnosis
Post by: camaro jock on June 26, 2014, 05:10:11 PM

I need a little assistance just got my Camaro out for the year and it starts and runs great til it warms up and it coughs and sputters bad. Could this be a faulty fuel pump? Car has 396 with quadrajet  I always like to look at carb last but acts like a carb problem, any ideas would be greatly appreciated. Thanks Darrell

Title: Re: Help in diagnosis
Post by: cook_dw on June 26, 2014, 06:52:43 PM

Make sure the choke is coming off and not sticking closed.

Title: Re: Help in diagnosis
Post by: camaro jock on June 26, 2014, 07:46:41 PM

Thanks, could that be in choke box? It looks like it does not open all the way, should it be straight up or closed partially?  Darrell

Title: Re: Help in diagnosis
Post by: cook_dw on June 26, 2014, 08:04:40 PM

I cant remember 100% on a q-jet but I want to say it opens to about 2/3s the way.  It should only be open about a 1/4 inch when choke is on.  If memory serves me.

Title: Re: Help in diagnosis
Post by: BULLITT65 on June 26, 2014, 09:09:42 PM

It would be easy to check if that is the issue, once it is warm, manually open the choke and see if it makes a difference. I agree with Darrell it does sound like a choke problem.

Title: Re: Help in diagnosis
Post by: camaro jock on June 27, 2014, 01:38:46 AM

Thanks I will try this weekend, Darrell

Title: Re: Help in diagnosis
Post by: hotrod68 on June 27, 2014, 06:56:11 AM

  Easy enough. Once it warms up take the air cleaner lid off and see if the choke is open. Or start it up cold and see if the choke opens as it warms up. It could be the accelerator pump. This damned ethanol gas eats up rubber like Ms PacMan. Once things get warm and expand, the pump diaphragm could be letting gas slide by it, causing the stumble. On the electrical side, I've seen coils break down when warmed up and the symptoms are similiar. Hard to pin down, but when in doubt revert to the basics. It's likely something very simple. Good luck and hope this helps.

Title: Re: Help in diagnosis
Post by: camaro jock on June 27, 2014, 11:25:53 AM

Was not thinking of the accelerator pump, that is a good idea, do you think  I could rule out the fuel pump? Thanks Darrell

Title: Re: Help in diagnosis
Post by: BULLITT65 on June 27, 2014, 01:20:26 PM

I helped my friend with his 76 Corvette a couple years back, he had the same problem. After going through 6 different things, it ended up being the spark plugs. They were fine until they heated up, then they started missing.... go figure.

Title: Re: Help in diagnosis
Post by: hotrod68 on June 28, 2014, 04:59:39 AM

  Probably not the fuel pump. Being mechanical it either works or it doesn't. But it wouldn't hurt to pull the dipstick and smell for gas. If the diaphragm is leaking it's going straight into the engine oil.
   Excellent suggestion, Bullitt. And if the choke was sticking, it'd load them up even more and make them foul.