No Gas to the Carb When Engine Warms Up

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valiantwagonguy said:
Last summer I had the same problem in my 76 Dodge Aspen with a slant 6 .I went thru the entire car prepping for a 2000 mile road trip.Put in a new fuel pump too.Went on the trip.Everything was fine but the morning after I returned it started to act just like your car is. I checked everything and finally came to the conclusion that the ethanol in the gas wiped out the fuel pump diaphragm . Bought another "new " fuel pump and the problem was solved.Don't assume just because it's new it's good
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The pump is only a week old and only has about 10 miles. It could be bad.
 
I have had this problem before. I would be willing to bet the fuel line between the tank and fuel pump has pin holes in it. Look at the rubber lines. Look where the rubber line that comes out of the tank and goes into the steel line. The fuel pump has to be able to pull fuel, any small hole in a line and it will get nothing but air.
 
Killer6 said:
The OP has stated new pick-up, tank, pump, EFI hose tank to line. Was the strainer new with the pick-up assy.??
If the float or needle is sticking, the carb will run dry, and the engine heat will cause a large vapor bubble that will stay trapped until conditions change. The old school way
to check is to tap on the carb body somewhere relatively harmless with a plastic screwdriver handle to see if it frees up, while the car is running poorly & before it quits
running completely.
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When it's idling the filter empties. The engine never quits idling or runs rough. The strainer was new with the pick up.
 
Hellrats said:
I have had this problem before. I would be willing to bet the fuel line between the tank and fuel pump has pin holes in it. Look at the rubber lines. Look where the rubber line that comes out of the tank and goes into the steel line. The fuel pump has to be able to pull fuel, any small hole in a line and it will get nothing but air.
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I replaced the rubber hose, with a fuel injection hose. Do you think the steel line has a pin hole somewhere?
 
Tooljunkie said:
Or a ball of t-tape caught in the inlet. I remember t-tape on quadra-jets being quite popular. Wrong but they done it anyways.

So when it quits,immediately pull fuel line off at carb, slip a rubber hose over fitting and put it in a container. Crank for 30 seconds.
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Thanks. I'll try that.
 
Show me a picture of where the fuel pump is picking up the fuel. I want to see what line it is attached to. Sometimes guys attach it to the wrong line at the attach the hose to the return line by mistake. Been there done that.
 
The
slantsixdan said:
No, a stalling problem like this will not (cannot) be caused by a horizontal fuel filter.

No, you do not need (and really do not want) to go adding electric fuel pumps. You're not having this problem because the car doesn't have an electric fuel pump; once you find and fix the problem it will go away.

Two items not yet mentioned: the rubber hose from the hard line to the inlet of the fuel pump, and the strainer on the end of the fuel pickup pipe inside the tank (part of the sender): new, old, absent?
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The stainer on the pick up is there and clean. The rubber hose to the pump is new.
 
rumblefish360 said:
Show me a picture of where the fuel pump is picking up the fuel. I want to see what line it is attached to. Sometimes guys attach it to the wrong line at the attach the hose to the return line by mistake. Been there done that.
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I'll send a picture tomorrow. I just had the trunk floor replaced, so the tank was out of the car. I
 
Another anecdote.
My 77 jimmy would idle fine.
But try to move it or even rock it, engine would quit.
So i pressurized gas tank. There was gas squirting out from holes in the steel line. Fixed that but still had the problem.
3-1/2 gallons of water in the tank....
 
Hellrats said:
I have had this problem before. I would be willing to bet the fuel line between the tank and fuel pump has pin holes in it. Look at the rubber lines. Look where the rubber line that comes out of the tank and goes into the steel line. The fuel pump has to be able to pull fuel, any small hole in a line and it will get nothing but air.
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If it's sucking air, should I have the gas cap on? One reply I got previously, said I may have a venting problem. Any thoughts?
 
Tooljunkie said:
Another anecdote.
My 77 jimmy would idle fine.
But try to move it or even rock it, engine would quit.
So i pressurized gas tank. There was gas squirting out from holes in the steel line. Fixed that but still had the problem.
3-1/2 gallons of water in the tank....
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I'll check that after a run a couple of other tests. I drained the tank so there shouldn't be any water.
 
Yes, my post above. You could actually have the gas line hooked to the vent or return line.

Other than that, fuel lines hooked up wrong on the tank itself, dirty sock on the pick up, clogged line.

That’s all I got....
 
Money Pit said:
No. I have to let it sit for a few hours before the filter fills. Then it will restart.
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It's not "refilling", the bubble just went to the highest point. It's all uphill from the tank, and the float valve is a suction breaker. If /when the float opens, the air exits, and the fuel runs down to the low spot. And the same thing happens on the supply side; the air travels up to the highest part between the pump and the tank, some to the front perhaps and some back into the tank, or out a crack in the line or a where-ever, and whatever fuel was in the line runs downhill towards the lowest part usually under the passenger seat. Then when you restart it, the pump primes itself and pushes the gas up to the carb, and the air goes out the floatvalve, until the gas gets there. And the semi-transparent filter is the witness. Now this creates a low pressure in the supply line, and if the fuel level in the tank is high enough, it will travel up the pick-up over the top and on towards the front. But if air gets in there, then , well, you know what happens ,then.
 
Money Pit said:
If it's sucking air, should I have the gas cap on? One reply I got previously, said I may have a venting problem. Any thoughts?
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No it's not a vent problem. The fuel pump has to have nothing but a liquid to pull. It would have to be small pin holes in the lines between the tank and the fuel pump.
 
I don't know if you tried what tooljunkie said about breaking the fuel line loose at the carb and cranking it to see if it is pumping gas but I had a similar problem with my 1980 Volare with a 225. I replaced all the stuff like you have and still it kept stalling. I decided to pull the top off the carburetor the next time it did it and what I found was an empty bowl but the reason was that the float was sticking at the top. It was rubbing the side of the carb bowl just enough to stick. I bent the arms to the floats ever so slightly to get free movement and it cured it. I was shouting hallelujahs.
 
Pin holes will be witnesses, except when they occur higher than the fuel-level in the tank.
I severe restriction, on the suction side, can cause the fuel to "boil" in the line as the pressure drops. Now you have both liquid fuel and gaseous fuel in the line. That would explain the engine running on the empty filter I suppose......... cuz it's not actually "empty", but rather full of gaseous fuel.
And once again, the fuel flow test will show bubbles in the pumped fuel, that should not be there.
 
Take the filter off under the hood, and see if you can blow back into the tank.

I still think you have something clogging the sender unit filter. Have any enemies? Been friendly with the neighbors wife recently?
 
nckennyb said:
I don't know if you tried what tooljunkie said about breaking the fuel line loose at the carb and cranking it to see if it is pumping gas but I had a similar problem with my 1980 Volare with a 225. I replaced all the stuff like you have and still it kept stalling. I decided to pull the top off the carburetor the next time it did it and what I found was an empty bowl but the reason was that the float was sticking at the top. It was rubbing the side of the carb bowl just enough to stick. I bent the arms to the floats ever so slightly to get free movement and it cured it. I was shouting hallelujahs.
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I've pulled the line and cranked the engine. I'm getting gas to the carb. I haven't checked to see how much fuel I'm getting in 30 sec, yet.
 
Mr Gorsky said:
Take the filter off under the hood, and see if you can blow back into the tank.

I still think you have something clogging the sender unit filter. Have any enemies? Been friendly with the neighbors wife recently?
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I pulled the pick up today. I blew through the pick up. it's clear. The strainer is very clean.
 
I know you said it's a new tank, but if the gas is contaminated then the car will run until the sock on the pick-up is blocked. If you blow down the line it'll clear and the car will run again for a while.

If you leave the car overnight, the contaminants can settle and the car will again run again for a while.
 
AJ/FormS said:
Pin holes will be witnesses, except when they occur higher than the fuel-level in the tank.
I severe restriction, on the suction side, can cause the fuel to "boil" in the line as the pressure drops. Now you have both liquid fuel and gaseous fuel in the line. That would explain the engine running on the empty filter I suppose......... cuz it's not actually "empty", but rather full of gaseous fuel.
And once again, the fuel flow test will show bubbles in the pumped fuel, that should not be there.
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That makes sense. the engine never stops when it's idling or when I rev the engine. I'm anxious to try the flow test. Like I mentioned, I just had the trunk floor replaced. May be the fuel line was kinked or has a pin hole. I'll check it tomorrow. Thanks
 
Money Pit said:
I'll check that after a run a couple of other tests. I drained the tank so there shouldn't be any water.
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OK, as I understand it, this problem did not exist until You had the trunk pan replaced. That can mean the following;
1) They bent the line out of their way while working, kinking it and restricting the flow of fuel even after bending it back.
2) With it disconnected, debris got into the line/hose and ended up somewhere between the tank & pump.
3) It is just a stone-stupid coincidence, and has nothing to do with Your problem.
As far as what You've already done;
1) Almost an entirely new fuel system save for the OE hard-lines & carb. You've adjusted the float level, why, and what adjustment was needed if any?
2) Run the car with the fuel cap off,......Driving the vehicle, or just sitting still? It stalled without the fuel cap, correct?
What I doubt is the issue;
1) Hoses hooked up wrong. It would've been difficult to do in the first place, and the lines are different sizes. The vent tube is at the very top of the tank, & unless the
tank was filled to the brim, You wouldn't be getting any fuel period.
2) Tank venting. Besides the cap off test, if the tank had developed a vacuum that stopped the flow of fuel, simply removing the cap would allow atmosphere in at once,
with the accompanying "suction release" sound. The pump would be able to re-establish flow fairly quickly, not 15 minutes.
3) Pinholes in the fuel line. While they can cause aeration of the fuel, they wouldn't allow for the vehicle to drive 15-30 minutes before rearing their ugly head. There
should be signs of excessive foaming in the filter, & the supply of fuel would be inconsistent with a "lean surge" like driveability issue coming & going. Hot or cold.
 
I’ve had a new fuel pump collapse the old piece of rubber hose that fed it... just a thought if most of the system is new...
 
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