Car dies after driving about 1/2 hour

[computercarguy]

Don't forget the small hose that connects the main fuel line to the piece that runs parallel to the inner fender, located near the brake combination valve. Maybe it is collapsing in on itself or the inner lining is breaking down, blocking fuel.

 

[Hemikiller]

Don't forget the small hose that connects the main fuel line to the piece that runs parallel to the inner fender, located near the brake combination valve. Maybe it is collapsing in on itself or the inner lining is breaking down, blocking fuel.

Agreed, verify this piece of hose is good. 

FWIW, considering that a fuel pump is $13, put a new one in. It should run from an external can until it is empty.

 

[Danno]

Don't forget the small hose that connects the main fuel line to the piece that runs parallel to the inner fender, located near the brake combination valve. Maybe it is collapsing in on itself or the inner lining is breaking down, blocking fuel.

Agreed, verify this piece of hose is good. 

FWIW, considering that a fuel pump is $13, put a new one in. It should run from an external can until it is empty.

Yes, the piece that connects directly to the fuel pump, from the front left wheel well. I have replaced that, also the one in back that connects from the line to the sending unit.

Concentrating on the main fuel line now being that it runs ok when hooked directly to the pump with a rubber hose to the external can, but not when a hose connected to the rear end of the line into a can it dies after about 15-20 minutes.

 

[Danno]

Don't forget the small hose that connects the main fuel line to the piece that runs parallel to the inner fender, located near the brake combination valve. Maybe it is collapsing in on itself or the inner lining is breaking down, blocking fuel.

Agreed, verify this piece of hose is good. 

FWIW, considering that a fuel pump is $13, put a new one in. It should run from an external can until it is empty.

Yes, the piece that connects directly to the fuel pump, from the front left wheel well. I have replaced that, also the one in back that connects from the line to the sending unit.

Concentrating on the main fuel line now being that it runs ok when hooked directly to the pump with a rubber hose to the external can, but not when a hose connected to the rear end of the line into a can it dies after about 15-20 minutes.

Just reread your reply about that short piece of hose. I'll look for it, didn't realize there was another rubber hose connection besides the 2 I mention I had changed.

 

[Danno]

Agreed, verify this piece of hose is good. 

FWIW, considering that a fuel pump is $13, put a new one in. It should run from an external can until it is empty.

Yes, the piece that connects directly to the fuel pump, from the front left wheel well. I have replaced that, also the one in back that connects from the line to the sending unit.

Concentrating on the main fuel line now being that it runs ok when hooked directly to the pump with a rubber hose to the external can, but not when a hose connected to the rear end of the line into a can it dies after about 15-20 minutes.

Just reread your reply about that short piece of hose. I'll look for it, didn't realize there was another rubber hose connection besides the 2 I mention I had changed.

Update: did a vacuum check on the main fuel line, it is a tight as a frog's ass (watertight), reconnected everything back to where it should go and started the engine and it ran for an hour until I shut it off.

All I have done is replace 2 short pieces of fuel line, one at the pump, and one at the sending unit, and  blew a good volume of air through the main fuel line before I vacuum checked it.

I'll check it idling again today, then start on short trips. The weather has cooled, so maybe the overheating coil theory, or vapor lock is valid.

Forgot to mention, I did check the coil with a meter, and the findings were marginal. Maybe I'll throw a coil at it for grins...…...Thanks for all the tips...……………….. :thankyouyellow:

 

[Danno]

Yes, the piece that connects directly to the fuel pump, from the front left wheel well. I have replaced that, also the one in back that connects from the line to the sending unit.

Concentrating on the main fuel line now being that it runs ok when hooked directly to the pump with a rubber hose to the external can, but not when a hose connected to the rear end of the line into a can it dies after about 15-20 minutes.

Just reread your reply about that short piece of hose. I'll look for it, didn't realize there was another rubber hose connection besides the 2 I mention I had changed.

Spoke too soon!

I did a restart yesterday with it all hooked up like it was when it ran for an hour

Update: did a vacuum check on the main fuel line, it is a tight as a frog's ass (watertight), reconnected everything back to where it should go and started the engine and it ran for an hour until I shut it off.

All I have done is replace 2 short pieces of fuel line, one at the pump, and one at the sending unit, and  blew a good volume of air through the main fuel line before I vacuum checked it.

I'll check it idling again today, then start on short trips. The weather has cooled, so maybe the overheating coil theory, or vapor lock is valid.

Forgot to mention, I did check the coil with a meter, and the findings were marginal. Maybe I'll throw a coil at it for grins...…...Thanks for all the tips...……………….. :thankyouyellow:

I spoke too soon. I ran it again yesterday under the same conditions as the successful 1 hour run previous and it died after about 25 minutes. Where exactly, is that piece of hose you're talking about?

Now thinking about the coil, then something inside the tank...….

 

[73pony]

Have you tried the suggestion to run the long piece of fuel line from the tank pick up to the fuel pump thus keeping all systems in play except the main fuel line? I really think this is the issue. If it was the coil breaking down it would do it every time and you alreadys posted that a gas can at the front by fuel pump it didn’t die but when you ran from a gas can at the rear only eliminating the fuel tank it still died. This tells me it it the main fuel line and the above test will confirm this if it runs fine.

 

[Carolina_Mountain_Mustangs]

I believe the section of hose he is referring to is on the other side of the inner fender directly under the proportioning valve for brakes. Hooks to the larger diameter metal line circled. It is easy to kink sometimes also. Might need a spring on the outside of it to prevent kink.

 

[Danno]

Have you tried the suggestion to run the long piece of fuel line from the tank pick up to the fuel pump thus keeping all systems in play except the main fuel line? I really think this is the issue. If it was the coil breaking down it would do it every time and you alreadys posted that a gas can at the front by fuel pump it didn’t die but when you ran from a gas can at the rear only eliminating the fuel tank it still died. This tells me it it the main fuel line and the above test will confirm this if it runs fine.

Just ran it again, for almost an hour, until I shut it off with the key. Poking around, I found the plug (cover?) for the vacuum test port in the back of the engine was cracked and dry. I temp. plugged it with a piece of fuel line with a bolt in it. There was actually  not too much difference in the idle while the port was open to when it was plugged. The engine idled smooth.

 This dying  problem is intermittent, and hard to duplicate. I hate to pay $30 for 9' of rubber fuel line that I'll only use once, but I may have to...………….

 

[Don C]

Do you have a heat gun, or a hair dryer? Heat the coil up and see if that recreates the problem. Same with the distributor, heat it up below the cap, or take the cap off and heat up the condenser. While you're in there, check the point gap.

 

[Danno]

Do you have a heat gun, or a hair dryer? Heat the coil up and see if that recreates the problem. Same with the distributor, heat it up below the cap, or take the cap off and heat up the condenser. While you're in there, check the point gap.

Still fighting this intermittent problem:

I have replaced the coil

Checked and cleaned the points and reset them

Removed and cleaned the condenser connection

Changed all three rubber fuel lines

Pressure (vacuum) checked the main fuel line, and its tight

I did a check, by feel, of the main fuel line and there are no kinks or damage I could feel

Blew air thru the main fuel line with it open on both ends

Blew a little air thru the same line with it connected to the sending unit with the gas cap off

It runs until I shut it off when hooked in front to a remote gas can directly hooked to the fuel pump

It dies after 20-30 minutes when hooked to the aft end of the main fuel line, there was still fuel in the line when I removed it from the gas can

I disconnected the line before the filter at the carb right after it died and cranked the engine and got a token spurt of gas, then nothing

Could the pump be too weak to pull gas indefinitely all the way from the tank, but strong enough to pump gas through a short run from the can when hooked to the front? 

I'm thinking of buying a fuel pump, but will wait and see what people have to say.

This situation exists whether the fuel is coming from the tank normally, or from a remote can from the hooked to back of the line. :shootself: :shootself: :shootself: :shootself: :shootself:

 

[Don C]

Drain the tank and pull the sending unit/fuel pickup. Check the sock condition and the pickup tube. The tube might be corroded or have a pinhole in it. While you have it out check the condition of the inside of the tank, and how much gunk is sitting on the bottom of it.

 

[clevelandcoupe]

I'm still beting on a bad sock !!!!

 

[Danno]

I'm still beting on a bad sock !!!!

These checks were made from the front and back with a remote can. The tank pickup was not used in the last few engine runs...……….That's probably my next "dart" though. I only have about 1/8th of a tank of gas. so if I get the left side up high enough, I shouldn't have too big of a mess...…….. :-/

 

[turtle5353]

As cheap as these parts are , I would just put a new pump, hardline, and pick up. Be done with it.

 

[clevelandcoupe]

I agree with Turtle. If your taking out the pick up, which could be damaged during removal, just replace.

Thanks, Jay

 

[Danno]

As cheap as these parts are , I would just put a new pump, hardline, and pick up.  Be done with it.

:bravo: :goodpost:

 

[Hemikiller]

Agreed. Pump is around $13, swap it out

 

[Studdley]

Check your oil too, on my 72 the fuel pump diaphragm popped and filled my crankcase with gas

 

[Danno]

Agreed. Pump is around $13, swap it out

Changed the pump, and guardedly saying that this was the culprit. It's running fine now, idling for an hour with no hint of dying.

Now I think I've created another problem. After all the idling in the driveway over the past few weeks, mostly in hot weather, during the troubleshooting, I think I may have damaged my starter.

Now when I go to start the car, the starter really sounds like it's laboring. Just went to get gas, and at first it wouldn't restart, like it was laboring or a low battery. Then it reluctantly started, but the starter sounded different. The battery shows good voltage, so I'm guessing I've partially fried my starter? :shootself: