64 Valiant Fuel Problems, PLEASE HELP

-

Sugnet 200

New Member
Joined
May 6, 2022
Messages
2
Reaction score
1
Location
Portland
First I replaced the fuel pump. Didnt help. Made sure the fuel line is clear by blowing air through it, seems to be fine. Figured the problem was in the tank, replaced that and the sending unit. FUEL IS STILL NOT MAKING ITS WAY TO THE PUMP.

Any Suggestions?
 
Have you closely inspected all of the rubber hose in the system? It breaks down over time and can act like a check valve stopping flow. Whenever I replace a tank, I always replace the small sections of rubber hose.
 
Have you closely inspected all of the rubber hose in the system? It breaks down over time and can act like a check valve stopping flow. Whenever I replace a tank, I always replace the small sections of rubber hose.
There is only a short piece of hose about 4 inches long between the tank and the line. You think that could be the issue?
 
There is only a short piece of hose about 4 inches long between the tank and the line. You think that could be the issue?
...and between the pump and supply line. what about the filter? Aren't there a couple of short pieces there? And yes, it could be the problem. I ain't promisin anything since I ain't standin there.
 
Agree with RRR, cheap first blast from the shot gun.

To locate the problem do some testing.

There are 15 places that could be a cause of no fuel to the carb.
  1. Fuel tank vent
  2. Fuel pickup sock
  3. Fuel pickup tube
  4. Hose from fuel pickup to hard lines
  5. Hard line clogged
  6. Hard line to fuel pump hose
  7. Fuel pump
  8. Fuel pump eccentric
  9. Hard line to fuel filter
  10. Hose from hard line to filter
  11. Filter
  12. Hose from filter to carb
  13. Hard line from filter to carb
  14. Carb float
  15. Idle circuit in carb.
If there was a leak of blockage at any of those locations that could case your problem.

The nice thing is you can test at just about every point.

But start at the carb and work back.
 
Sometimes it helps to prime the pump to get it working right. Which engine do you have? If whatever operates the pump is bad, all the new parts in the world aren't going to make it work. I like to use a MityVac to get fuel up from the tank and through the pump. I usually hook it up to the line or hose going to the carb inlet. I also fill the carb float bowl on carbs that allow that. If not, I just squirt some gas down the intake so the engine will start and get the pump moving faster than it would just cranking the engine over with the starter.
 
Disconnect the line at the fuel pump then take a rag and some pressurized air from the compressor and blow into the tank and see if fuel blows out the line
 
IS IT POSSIBLE that the needle and seat is stuck shut? Have you tested it by cranking the engine with an open line?
 
Make sure the metal section has not rusted somewhere.
 
Use a piece of rubber hose and hook it to the inlet side of the fuel pump and run the other end into a gas can and try to fire the car. If it runs on the can you have eliminated the fuel pump and carb as the problem. Next, buy or borrow an electric fuel pump and hook the rubber hose to the hard line going to the tank, start the pump and see if it draws fuel. If not, hook your rubber hose to the other end of the fuel line and into the gas can and see if the pump draws fuel through just the hard line, if so, the hard line is unobstructed, and must be either the rubber hose going to the tank, or the gas cap vent, if the tank and sending unit are both new.

I just did this on this old Trail Duster that had been sitting for 3 years, turns out it was the rubber hose at the front of the hard line that went to the fuel pump, as Rusty mentioned.

DB756FC5-59A8-41F8-A974-057A7DFBE366.jpeg
 
I am having a similar problem with my 64 Valiant. If the car sits for a few days, it will not pull fuel from the tank, on the starter. Tried using a electric pump, and pumping into a container. There was not a lot of flow, and the fuel had a lot of "bubbles". I disconnected the steel line at the tank, and put a rubber cap on the line. Then used the "MityVac at the other end of the steel line (inlet of the pump). I could not pull a vacuum. I am assuming I have a pin hole in the steel line. I am waiting for the 5/16 NiCopp line to get here on Monday. Going to replace the complete fuel line.
PS: When replaceing the rubber hoses, use the hose for fuel injection. I think it is R9, not the old R7 type for carbs. It is much more tolerant of ethanol fuels.
 
Air getting into the line somewhere. Your job "Ethan" is to find it!
 
its a vaccum pump. air getting in somewhere. My guess is the tank to hard line rubber piece. remove it and cap the hard line side, check for vacuum at fuel pump inlet. If you cannot pull it, apply pressure to hard line section with mighty vac pressure nipple and use some soapy water in a spray bottle to spray the hard line sections looking for bubbles.
 
Disconnect the line at the fuel pump then take a rag and some pressurized air from the compressor and blow into the tank and see if fuel blows out the line
I'd be a bit careful doing that. Just a couple lbs of air pressure is enough. More than that can cause other problems, although I have used that method to take big dents out of tanks. :) I've also seen floats collapse, so, If I'm going to put lots of pressure in the tank, I pull the sender and put a sealed converted sender plate in it's place before pressurizing the (empty) tank. When I had a repair shop, one of my guys pressurized a tank trying to get fuel to come out and managed to blow a half dollar sized hole in the bottom of the tank. It turns out the tank had a rust hole that had been repaired with a patch. The extra pressure was more than that patch could take. Not a common problem, but, something similar could easily happen on on old tank. Suddenly having an inch and half hole in a tank with 15+ gallons of gasoline inside is not something you want to happen in your garage! :mad: What a mess that was!
 
I'd be a bit careful doing that. Just a couple lbs of air pressure is enough. More than that can cause other problems, although I have used that method to take big dents out of tanks. :) I've also seen floats collapse, so, If I'm going to put lots of pressure in the tank, I pull the sender and put a sealed converted sender plate in it's place before pressurizing the (empty) tank. When I had a repair shop, one of my guys pressurized a tank trying to get fuel to come out and managed to blow a half dollar sized hole in the bottom of the tank. It turns out the tank had a rust hole that had been repaired with a patch. The extra pressure was more than that patch could take. Not a common problem, but, something similar could easily happen on on old tank. Suddenly having an inch and half hole in a tank with 15+ gallons of gasoline inside is not something you want to happen in your garage! :mad: What a mess that was!
Yeah I know what you mean that's why I threw the rag part in there ,it's not going to seal anything..and the gas if the line is clear will fire out in hot second ...mystery solved.
Never heard of not just replacing the tank. Crazy story.
Thanks.
 
If all else fails go over to MyMopar and download a service manual. There is a procedure in there to check the pump with a vacuum gauge.

Someone mentioned air. If the fuel line tube from tank to pump has some pinholes it may ingress air
 
I pressurized my tank with an air blower off a compressor and blew out a dent from hitting an island. Worked great! It also blew the sock apart as it was full of rust.
 
Run a rubber line to the pump from a gas can and see if it starts, that way you can eliminate other issues. Also make sure you at least have 2 gallons in the tank.
 
Where do you have the filter located, before or after the pump?
 
Tell us what Doug says.... My solution is a $12 Facet electric fuel pump.

Drill a hole in the floor of the lifter valley above the fuel pump lever to allow oil to drip onto the cam lobe and fuel pump lever. The specific instructions are in the book which I highly recommend any one who likes or owns slant sixes get a copy.
 
sounds like a preemptive strike on a functional lobe, not much results after the lobe has gone flat. Noted, and thanks!
 
-
Back
Top