Fuel Supply Problem
05-06-2010, 09:26 PM
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Fuel Supply Problem
My truck failed to start for the first time a few days ago. Fortunately this happened at home next to the work shop so it was in a perfect place to check it out. The problem is a no fuel issue. It ran fine, I parked it and next day it made an attempt to start but no start. I may have run it out of fuel. The fuel sender does not work and I was driving it by miles on the trip meter. I just lost track of mile and gallons.
Troubleshooting the fuel system, I found the short pre-filter to lift pump hose had air leaks. I cleaned out the pre-filter screen and it had a good amount of crud in it. I then wanted to check the lift pump primer and fuel supply line. I attached a clear hose to the lift pump inlet, filled it with fuel and primer worked. I then attached it to the pre-filter outlet and here is where I have a problem.
First, I tried blowing air, by mouth, into the hose and back to the tank. All I could do is compress the air. I could not moved any air to the tank. Then I used a fuel cap with an air fitting and pumped a few pounds of air into the tank. I put the hose in a container with water. At first, I saw a few air bubbles come out then it stopped. Adding more air to the tank, I would not see any air bubbles nor fuel at the hose but I could hear an air leak in the area of the fuel module. I sprayed that area with soapy water but could not fine where the air leak was occurring. So, I may have a plugged fuel supply line.
Is there a check valve in the tank that would prevent me from blowing air from the pre-filter into the tank?
If the supply line is clear would I see air bubbles or fuel coming out of the hose with a few pounds of air pressure in the tank? How much pressure can I use? I had the air pressure set low so as not to damage anything but it should have moved air or fuel.
Tomorrow I am going to remove the short rubber line behind the fuel filter to see what I have. For those who have installed all rubber supply and return hose engine to tank, do you run the hose along the metal lines or do you route them over the tank or some other way?
Thanks for any help and advice.
Troubleshooting the fuel system, I found the short pre-filter to lift pump hose had air leaks. I cleaned out the pre-filter screen and it had a good amount of crud in it. I then wanted to check the lift pump primer and fuel supply line. I attached a clear hose to the lift pump inlet, filled it with fuel and primer worked. I then attached it to the pre-filter outlet and here is where I have a problem.
First, I tried blowing air, by mouth, into the hose and back to the tank. All I could do is compress the air. I could not moved any air to the tank. Then I used a fuel cap with an air fitting and pumped a few pounds of air into the tank. I put the hose in a container with water. At first, I saw a few air bubbles come out then it stopped. Adding more air to the tank, I would not see any air bubbles nor fuel at the hose but I could hear an air leak in the area of the fuel module. I sprayed that area with soapy water but could not fine where the air leak was occurring. So, I may have a plugged fuel supply line.
Is there a check valve in the tank that would prevent me from blowing air from the pre-filter into the tank?
If the supply line is clear would I see air bubbles or fuel coming out of the hose with a few pounds of air pressure in the tank? How much pressure can I use? I had the air pressure set low so as not to damage anything but it should have moved air or fuel.
Tomorrow I am going to remove the short rubber line behind the fuel filter to see what I have. For those who have installed all rubber supply and return hose engine to tank, do you run the hose along the metal lines or do you route them over the tank or some other way?
Thanks for any help and advice.
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