fuel delivery problem

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purplescamper

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I have a 73 scamp with a 360 4bbl that I'm putting togather.
I has a new fuel tank and sending unit and new fuel lines. I installed a new carter mech. fuel pump and an inline fuel pressure gauge, in the back I have a canister fuel filter above the tank.
I went to start the car and it wanted to start, but would stay running for about a second
the fuel pressure gauge said I had no pressure, I checked for leaks, kinked lines and blew air into them to make sure there were no clogs, I didn't find anything.
the next thing I did was buy a carter electric fuel pump which I installed, I had the same problem no pressure up front. next I put the pressure gauge after the fuel pump the gauge said I only had 2psi. from the pump.
thinking that maybe the fuel filter was restricting the flow I removed it and bypassed it
I have also removed the sending unit to see if the sock was mucked up. it wasn't.
the pump continues to run all the time sometimes dropping to 1psi, sometimes it spins like its pumping no fluid, even though I put 6 gallons of gas in it.
I don't seem to be pumping fuel with either pump any ideas ?
100_2521.JPG
 
try that first, that will tell us if your having vent issues and pulling a vacuum
(im sure the holley can handle it, but i dont know if the carter could)
 
Hey Purplescamper,
Try this.
Get some rubber fuel line. Detach the line from the tank side of your fuel pump. Attach the rubber line to the tank side of the fuel pump and run it into a gas container full of fuel. Start car. If the car starts, your problem is towards the rear. Re-attach the cars fuel line to the fuel pump. Detach the cars fuel line from the tank and attach the rubber fuel hose used earlier. Run it to the gas container. Start car .If it doesn't start, fuel line is the problem. If the car does start , next check is to eliminate the Tank sending unit. Take the gas line out of the gas container and run into fuel tank. Start car. If you are able to start the car, the problem is the tank sending unit or the tank is not properly vented.

Hope this is of some help.
 
AAndrews said:
Hey Purplescamper,
Try this.
Get some rubber fuel line. Detach the line from the tank side of your fuel pump. Attach the rubber line to the tank side of the fuel pump and run it into a gas container full of fuel. Start car. If the car starts, your problem is towards the rear. Re-attach the cars fuel line to the fuel pump. Detach the cars fuel line from the tank and attach the rubber fuel hose used earlier. Run it to the gas container. Start car .If it doesn't start, fuel line is the problem. If the car does start , next check is to eliminate the Tank sending unit. Take the gas line out of the gas container and run into fuel tank. Start car. If you are able to start the car, the problem is the tank sending unit or the tank is not properly vented.

Hope this is of some help.
Click to expand...
thanks, when I come home later ill try this
 
Did you ensure the new sending unit was to the bottom of the fuel tank? If it's not that could be your issue. I'd personally put some more fuel in it to see before I went too crazy trouble shooting.
 
If the electric pump is before the mechanical pump it will not be able to push fuel through. I know from experience on that. Mechanical pump is like a road block to the electric pump.
 
I took the mechanical pump off before I installed the electric one..i just up hooked the line from the electric fuel pump to the tank. I put the one end of the fuel line into a raised 1 gallon fuel can ( so I could gravity feed the fuel pump) turned on the pump got no reading on my pressure gauge, switched pressure gauge still no reading, but the pump was running
 
Now I just re-read your original post. You say the fuel filter is above the tank? That would be a no-no. You don't ever want to make the gas run uphill any more than absolutely necessary. I doubt that this is all of your problem, but it could contribute to it.
 
With 0 pressure on the gauge with your setup now it has to be the pump or the gauge. Make sure polarity on pump is correct. The engine still will not run in your last configuration? Try to jump pump with someone's help and see if pump will give you fuel with a can to receive the fuel. Again make sure pump polarity is correct.
 
tonysrt said:
With 0 pressure on the gauge with your setup now it has to be the pump or the gauge. Make sure polarity on pump is correct. The engine still will not run in your last configuration? Try to jump pump with someone's help and see if pump will give you fuel with a can to receive the fuel. Again make sure pump polarity is correct.
Click to expand...
the polarity is correct just for fun I switch them....same results
 
purplescamper said:
right above tank on the support
Click to expand...

uphill ?

got a gas can handy?

why not disconnect the pump from the pickup, and run a short hose into a gascan, to see if the pump is willing to draw out of that?
infact, disconnect the outlet of the pump and run a hose back into the gascan, to rule out the pump

once we know the pump works, pick one of the lines to hook it up again and see if it works now
eliminate one part of the path at once

speaking of which, did we eliminate all the soft line ?
checked all the clamps?

(one of our members, i forgot his name, always says IF you must use wormscrew hose clamps put two of them one, 180 degrees lapsed so that you gt a good seal)
any place you can suck in air the pump will take the easy way out and suck air instead of fuel
 
diymirage said:
uphill ?

got a gas can handy?

why not disconnect the pump from the pickup, and run a short hose into a gascan, to see if the pump is willing to draw out of that?
infact, disconnect the outlet of the pump and run a hose back into the gascan, to rule out the pump

once we know the pump works, pick one of the lines to hook it up again and see if it works now
eliminate one part of the path at once
Click to expand...
I tried that yesterday and it didn't work......is there a better place to mount the pump ?
 
I think everybody has given you an idea of what they think seems to be your problem. If the pump is not drawing fuel, what else could it be? It seems like you tried all the recommendations and still no fuel. Unless you have a hair ball stuck somewhere, I think the boys have run out of gas also.
 
purplescamper said:
I tried that yesterday and it didn't work......is there a better place to mount the pump ?
Click to expand...

tried it?
are you saying the pump wont pull out of a gas can into the engine?
that means there s an obstruction before the pump

i googled the instructions and carter specifies all pumps to be mounted BELOW the gas tank
 
diymirage said:
tried it?
are you saying the pump wont pull out of a gas can into the engine?
that means there s an obstruction before the pump

i googled the instructions and carter specifies all pumps to be mounted BELOW the gas tank
Click to expand...
the lowest point is the gas tank. last night I tried sucking out of a gas can trick BUT I left the pump output line hooked up, this time I did what you said and unhooked the output line and put the hose in an old metal can...it pumped, but when I put a pressure gage on it I got no reading
 
purplescamper said:
the lowest point is the gas tank. last night I tried sucking out of a gas can trick BUT I left the pump output line hooked up, this time I did what you said and unhooked the output line and put the hose in an old metal can...it pumped, but when I put a pressure gage on it I got no reading
Click to expand...
If you got fuel pumping out an open line the gauge will not register because there is flow out the end

I wonder...If that is true...have we verified there was no fuel getting to the carb?
AND it's not just pouring out into the engine?

In order to verify the pump, run it for a measured time and the measure how many gallons you got, to calculate the GPH flow
 
If I read this right, your fuel line comes from the tank, to the filter, to the electric fuel pump, then to the carb. If this is how it's set up, it won't work. I also have a Carter electric fuel pump. I had a cannister filter before the pump. I had to switch it do the pump was before the filter. Remember, electric fuel pumps are pushers, not pullers, so they need to have some help getting fuel flowing. This means mounting the pump as close AND as low as possible, so gravity helps get the flow going. Then mount the filter as low as is reasonable. Make sure you don't have a blockage in any lines.
 
UPDATE: with fuel being drawn from the fuel can, I rigged up a long bypass line from the can to the carb, I'm getting 3psi at the gauge. the engine starts and stalls run for about a second then dies
 
furyus2 said:
If I read this right, your fuel line comes from the tank, to the filter, to the electric fuel pump, then to the carb. If this is how it's set up, it won't work. I also have a Carter electric fuel pump. I had a cannister filter before the pump. I had to switch it do the pump was before the filter. Remember, electric fuel pumps are pushers, not pullers, so they need to have some help getting fuel flowing. This means mounting the pump as close AND as low as possible, so gravity helps get the flow going. Then mount the filter as low as is reasonable. Make sure you don't have a blockage in any lines.
Click to expand...
I removed the pump
 
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