• Got the Contributing Memberships stuff finally worked out and made up a thread as a sort of "How-To" to help people figure out how to participate. So if you need help figuring it out, here's the thread you need to take a look at -> http://www.corvetteflorida.com/forums/showthread.php?t=3581 Thank you, everyone! Rich Z.

Fuel vapor cansiter

Kap142

Kap142

New member
:banghead:I seem to be having a continuing problem with getting "Goldie" to run smoothly (she feels like she's running on about 7 1/2 cylinders).:banghead:
I have worked on the following:
Replaced all plugs with Platinums (none were fouled):thumbsup:
Checked dist cap for cracks (none):thumbsup:
Made sure all plug wires (their only a couple of months old) were securely on:thumbsup:
Have checked for some kind of grounding at the dist/dist cap (found none):thumbsup:
I have not checked each wire to make sure fire is coming through due to the clearance problems with a big block and little work space.:thumbsdown:

What I have found that makes me curious (not any wiser):shrug01: is that I have about half the pressure coming out of the right bank exhaust as I do out the left exhaust (could a closed heat valve on the right exhaust reduce pressure out the tail pipe?).:shrug01: I have also noticed very little air intake by the carb line returning to the fuel canister (isn't supposed to be kinda free flowing to return un used fuel/fuel vapor to the canister?).

I'm just all kinds of open for suggestions.

Oops forgot to add recently had the 36 year old Carter Q-jet rebuilt too and have added a pressure regulator into the fuel line to better control that too.
 
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Hi Ken, Since you've gone through the basic stuff and still with problem, why not have Greg who owns AntiVenom take a look at Goldie? He's not too far from you and is a vendor on this site. Besides, he really likes the classic vettes too and I'm sure he can get Goldie up to stratopheric form.
 
Thanks Mark, I'll give him a call early next week. Guess I'll just limp her on over there and sit with Greg till he say "uh huh" and resolves any issues she may have.

Ken
 
Ken, with what you've already done, it sure sounds like it might be a vacuum (or lack of)problem. Have you checked the PCV and EGR valves? I've heard that sharks like yours are suseptible to vacuum leaks at the headlights. Maybe pull of the vacuum line that runs to each headlight, plug them, and take Goldie for another spin. If I recall right, you just had some work done on the front end. It's possible that someone left a line off, or that one (or both) of the headlight actuators have developed a leak since the mishap. Hope that you have the GM manuals for Goldie! Sure wouldn't wanna go taking vacuum lines off without a picture of how to get them back on correctly. There might also be "one way" valves in the vacuum lines that got installed in the wrong direction. Greg sounds like the quickest and most accurate way to get this one fixed, but come on......, you KNOW that you love to rip apart that Vette! LOL No matter which way you go, keep us posted on the outcome. Hell, for THAT matter, the carb could still need tweaked.....
Andy
 
Ya know Andy their is far more I don't know about my C3 then I do know, even at this point but this is so far beyond my understanding that it's making me craz(ier).

I think I'll send Rochelle a PM and see if she can get me on the book for early Monday.

Goldie is such a bear when she runs like she can that this drives me farkin nuts and you watch and see it'll be something dumb a** simple I just didn't know to look at.

Thanks brother and BTW when is Corvettes in Venice this year?

Ken
 
Just D/L the flyer. It'll go out tomorrow now if you can just get Joe and Deb to bring the chips and salsa............................:thumbsup:
 
Kap142 said:
:

What I have found that makes me curious (not any wiser):shrug01: is that I have about half the pressure coming out of the right bank exhaust as I do out the left exhaust (could a closed heat valve on the right exhaust reduce pressure out the tail pipe?).:shrug01: I have also noticed very little air intake by the carb line returning to the fuel canister (isn't supposed to be kinda free flowing to return un used fuel/fuel vapor to the canister?).
Click to expand...

Hey Ken,

Sorry to hear you having some issues. Welcome to the world of vintage big block "stuff"!

You mentioned a lack of pressure on the right exhaust. The right side has your heat riser and it is designed to restrict the exhaust flow when the engine is cold. So, if you have not warmed her up, and your heat riser is working correctly, it will feel restricted. BUT, if the engine is warm, then you should not feel the restriction.

If someone has taken the right side exhaust down, they may have the flap on the inside of the heat riser stuck against the donut gasket. Done this myself before on my '69. Just reach down at the bottom of the right side exhaust manifold and grab the heat riser weight. If it makes an easy 1/4 turn, then it is free and you have at least eliminated that as a possibility.

You also mentioned the fuel return line. The big blocks with a single four barrel have a vented gas tank, which also have a special fuel filter (AC - GF-432, I hope I remember the number correctly for you) that both the supply and return lines go through. This item is not made in the US anymore (I think?). If this fuel filter clogs or the element inside breaks loose (this has happened to me), then you will get the feeling that the car is going through a vapor lock situation. It will run just ok, but if you try to get on it, it will not run very well.

I am not saying that these items are your problem, but they could be and each of these are pretty easy to diagnose.

I hope this helps.

Good luck
Rich
 
Thanks Rich, The heat riser valve does not seem to be the problem based on what you say. The valve has not been taken apart and does rotate a quarter turn so off we go from there. When I eventually resolve the issue I'll post all the ugly details
 
Ken, i agree with rich427 on the heat riser value. did u check to see if its moving by itself. not just by moving by hand. there is a coil spring that actuates it when warm.
See where its facing while cold, then look again at it when cars been running a few to see if it moves. check the pressure while cold and warm
This usually causes the back pressure on pass side exhaust til it opens. (warms)
Thats why cars with them had the pass side exhaust pipe and muffler usually wear out quicker then the drivers side, due to condensation building up
I took mine off and removed the butterfly inside it, as to retain stock appearance. Plus it was sticking shut from time to time which is why i dremmeled the inner flaps off the pivot shaft.. everything looks stock from exterior.
Regarding the fuel filter. Since u had the carb rebuilt you should be fine, as the filter is in the carb inlet on the quadrajet
The number filter GF-432 would be for a 68-69 car. If memory serves me right. Still in cali and dont have my books with me.
Again, the 72 quadrajets have the filter inside the carb inlet itself.
 
JeeeZ. I hate to say this but, ... Sometimes it is a simple problem in the worst place to get to. (hint,hint). Good Luck.
 
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