Today after showing my 1960 at a local show and shine I took her for a cruise. 15 minutes into the cruise she is working fine but starts to stall as I have to stop at a red light. I wasn't adroit enough to work the clutch, brake and gas so the car stalls. A couple of lads pull up along side me and offer to push me into a vacant parking lot.

I take off the breather and pull back on the accelerator linkage and notice no gass coming out of the jets. I call my Dad on my cell phone and he comes. We remove the fuel line from the carb and place it over the carb bowl. I turn over the engine and no fuel is being delivered.

Call a flat bed to bring her home.

Ironically nearby is a 1933 Chevy that's having clutch problems. He was driving home from the same show & shine. He is now awaiting a flat bed as well....

Attempt to start her once home trying the same tricks above but no go. Dad puts some gass into the bowl, the car now gets gass from the carb's jets.

Now the same thing has been happening to me over the past three years and since that time I've....

- Replaced the electric fuel pump with a GM mechanical...(originally thought this was the problem)...

- Replaced the original coil with an Accell
- Replaced points and condensor and ballist resistor
-Replaced original intake and Carter AFB with Edelbrock units...
- Replaced spark plug wires...

Is this a vapour lock problem and if so how do I trouble shoot it....????

TIA

 

Kenmo,

You have several possibilities:

1. Vapor lock, whereas the fuel to the pump has turned into vapor due to excess heat on the inlet side of the pump. This would "solve" itself once everything cooled back down. Long term fix is to insulate or move fuel line away from heat sources.

2. Blocked pump inlet due to crap in the fuel. Disconnect fuel line at the pump and see if fuel runs out? Long term, clean out tank and lines.

3. Or vent in the tank blocked causing a vacuum. Opening the gas cap would temporarily solve that. Long term, uncork vent.

4. Faulty pump. Always possible (check valve stuck open), and "could" fix itself temporarily. Long term fix is to replace pump.

If this occurred with the electric pump also, then doubt it is items 1 (electric pumps - if mounted properly near the tank, arn't prone to vapor lock) & 4 (doubt that 2 different style pumps would act the same way).

Also went to a show and shine today, and came away with a trophy and met a bunch of very nice people (even talked to some Mustang folks!).

Plasticman

 

Sure sounds like it!! I've had one in the past act in a very similar manner, and it was vapor lock. Usually vapor lock will occur when the fuel line passes too near something hot, such as an exhaust or intake manifold, and when idling around so as to help "heat soak" the line. Often can be cured by relocating the line slightly away from or insulating from the heat source.

The best way I know to troubleshoot is to insulate the suspect line & see if operation improves. You can also cool a hot line with ice temporarily to see if you can get it back to pumping fuel.

I'm sure some other folks wiill chime in with some suggestions, also.

 

#3 sounds the most likely to me. It's been many years since cars were made with vented caps and it's no suprise when a "standard" non-vented cap finds it's way onto a vented system.

 

I would think your problem would occur more frequently if it were a fuel cap venting problem, but it's possible and easy enough to check.

 

I have an aftermakret fuel tank made out of the type of plastic service station gas cans are made of. It's made for C1s and appears identical to the original except there is no baffle. Instead there is an large hole in the middle of the tank (ie: I can see the Vette's body underneath. This is inlieu of the baffle. I purchased it from Blue Ribbon Corvettes in Atlanta.

http://www.blueribbonproducts.com/

The old tank got rusty inside so I replaced it with this unit about 10 years ago.... BUT ever since I swapped tanks, it's a bit of a chore to fill up at a gas station. If I apply full presure to the gas pump gun, the gas will gush out onto my toes... Also when I take the cover off of the tank I can hear a slight sucking noise as air gushes in...

There is an air vent tube. I've taken off of the gas door of the Vette and blow into it. It appears fine...

 

Kenmo,

If you hear a sucking noise when you remove the gas cap, then the tank vent is not working (or so it would seem), since a vacuum in the tank should not occur if the tank is vented properly.

Check to make sure that when you blow into the vent hose, that it is connected to the inside of the tank (hose could be broken and your just blowing air through to where it is severed). Try applying air pressure to the vent hose, and see if pressure comes out of the gas fill connection (remove the gas cap first).

The vent hose could also be pinched sightly (and somes is clear, and sometimes it is not).

Plasticman

 

Another thing to consider is the flexibles fuel line from the frame line to the pump inlet. Old ones can start to deteriorate on the inside and it can suck shut from pump vacuum. After setting awhile it will relax and allow fuel to pass through again.

Tom

 

I agree, if it's vented there's nothing to suck as the tank would be at equaliztion. think I would start right there and figure out what's causing the sucking noise that you hear. Have had non vented caps do as you're describing but vent line could also cause. Let us know what it washes out to be as this subject comes up here on the forum quite often. Good luck

 

My gas cap is an oem cap. I believe it's non vented. Would a quick fix be to drill a few small holes in the gas cap and try that ?

Thanks

 

Ok, I'll offer my $0.02 worth. I would look first at the fuel pump. The diaphragm inside the pump could develop a tear or pinhole that would prevent any kind of any suction from occurring. There are also springs inside that could weaken or break with age effectively shutting down the pump. The next thing I would look at would be the strainer sock on the fuel pick-up. I had a 67 GTO back in the late 60's that would lean out and backfire at wide open throttle. After much frustration, I looked at the sock and found it full of crud and rust. Once gone, the car ran great. I just replaced my gas tank in my 62 and found the sock on the sending unit dark brown with crap and rust. A new sock looks remarkably different. Good Luck.

 

Leave the cap loose or off for a quick fix.

 

I know what about the gas vent line, but I've not heard of a vented gas cap. I'm 50 so I'm not young and I'm not really ancient (yet) BUT how is a vented gas cap different then a none vented one (obviously it's vented, but how is it vented).

I asked my 73 yr old Dad who does 90% of the work on his vehicles himself and he couldn't recall of a vented gas cap either....so please jog our memories....

Cheers

Kenmo

 

Vented gas caps do not totally seal the tank off when installed, they allow air to pass thru so as not to create a partial vacuum in the tank as fuel is being used. All of the earlier cars (read early 60's and before) were vented systems.

When EPA pollution regulations came along, the fuel system was sealed and it became a closed system, the gas cap totally sealed the tank to the outside air. Fuel vapors were no longer allowed to escape into the air. This system is still in use today.

But the difference in the two systems with regard to the gas filler cap is that one cap (the vented one) has a small hole somewhere in the cap above its gasket which allows the passage of air into and out of the tank. The unvented cap totally seals the tank filler opening from the outside. Corvette fuel tanks were vented (either by a vented filler cap or by a vent tube to the atmosphere) until at least 1966, not sure how much later!

 

The C-1s used a non-vented cap as they all had a separate vent hose to maintain atmospheric pressure in the tank. You can run a vented or a non-vented cap if you like. The only thing with a vented cap on these cars is that with a full tank you can get some gas seepage out of the vented cap especially in right turns. Fix your vent and use a non-vented cap and your problem should go away.

 

This is a vented gas cap for my 1967.



The toothpick demonstrates clear passage inside/outside.

 

here is Paragon's replacement cap (p/n 7033) for the C1s, note the word "VENTED" stamped on it:

 

'53-'56 and halfway through '57 used non-vented tanks and a vented cap; the vented tank appeared in mid-'57 (with a non-vented cap) and continued through '62. Midyear tanks were non-vented and used a vented cap, and this continued into the early C3's until evaporative emissions regulations vented the tank into a charcoal canister and the sealed cap became part of the package.

I'd verify that the tank vent line is open and functioning, and check the "sock" on the sender pickup - they're a very fine mesh, and over the years they can get plugged with varnish and sediment, severely restricting fuel flow.

 

It's a new tank (replaced about 10 yrs ago) but it's made of the type of plastic gas cans are made of. I've been told that unlike a metal tank these tanks require better ventilation. It has been explained to me that as the gas is removed, the plastic can start to move in on itself.

Also one side of the tank has the ventilation. The other doesn't. Perhaps I need to add another ventilation line.

I'm on vacation after thursday, so I'm going to play with the Vette then...

 

Never heard of a tank like that, what brand is it and do they have a website?