Can I bypass both fuel pumps and install a universal in-line pump? If so, which pump?
This is the operation of the fuel pumps as per the Alldata website.
The electric fuel pump system consists of two fuel pumps: a low pressure boost pump mounted in the fuel tank, and a high pressure fuel pump mounted on the frame rail. The low pressure pump is located with its inlets at the bottom of an internal sump in the fuel tank. This design provides for satisfactory fuel pump operation during extreme vehicle maneuvers and steep vehicle attitudes with low tank fill levels.
The low pressure electric fuel pump is used to provide pressurized fuel to the inlet of the high pressure pump and helps prevent noise and heating problems. The inlet of the low pressure fuel pump has a nylon filter on it to prevent dirt and other particulate matter from entering the system. Some vehicles use an external resistor in the low pressure pump circuit to reduce operating voltage to 11 volts.
The externally mounted high pressure fuel pump is capable of supplying 15.9 gallons of fuel per hour at a working pressure of 39 psi. The pump has an internal pressure relief valve to provide over-pressure protection in the event the fuel flow becomes restricted. Over-pressure is restricted to 123 psi and reduced fuel flow will result.
The system pressure is controlled by a pressure regulator on the engine.
Why do you want to bypass the fuel pump? Is there a fuel delivery problem or an electrical problem?
Yes, The truck has set for about a year and when I first tried to start it the pump was working properly. I changed the filter added fuel and it still wouldn't crank. I removed the hose and there was no fuel being pumped to the filter. I was looking for the most inexpensive way to fix the truck. Universal pumps are cheaper and easier to install. I am a college student and my funds are very limited! If you have ant suggestions please let me now.
You are saying that the car is not cranking. Do you mean the starter is not moving the engine? Or are you saying that the engine is cranking and it just won't start.
If you are trying to test for fuel flow, the fuel pump has a short prime cycle then it won't work till the engine is running. There is a test connection that can be grounded to work the fuel pump. Ranger/Bronco 11 - Connector is at right fender apron, next to carbon canister, in front of heater blower motor. Ground the terminal at the shorter end of the plug. Do not ground any other wire; it will damage the ignition (EEC IV) processor.
The inertia switch can stop the fuel pump from working.
The inertia switch is located below the instrument panel, to the right of the transmission hump. Its purpose is to shut off fuel to the engine in the event of a vehicle collision. To reset the switch the button on the top of the switch needs to be pushed in with the key off. Then turn the key off, then back on and see if there are any leaks. If there are no fuel leaks seen then try to start the truck.
This switch is used on vehicles with electric fuel pumps. This switch shuts off the fuel pump in the event of an accident. The switch consists of a steel ball held in place by a magnet. Upon sharp impact, the ball breaks loose from the magnet, rolls up a conical ramp, and strikes a target plate that opens the switch electrical contacts and shuts off the fuel pump. Once the switch is open, it must be manually reset before starting the vehicle.
Let me know if this information helps.
The more detailed information you give me it can help me answer your questions better.
The truck will turn over but will not start. However, it will run with starter fluid sprayed in it. I can't find the terminal you described. I have already dropped the tank and removed that pump.I don't now what to do to test the pump now and if its not the pump what to do next.
You may want to get some professional help with this job.
Before ever dropping the fuel tank to replace a fuel pump, you must test the circuits powering the pump first. Like TechHelp2 suggested it could be as simple as the "inertia switch" cutting off power. The test connector he's referring to probably won't help now that the tank is on the ground.
You can also listen to the fuel tank (while still installed) for noise from the pump with the key on for 2 seconds, or while cranking. No noise, check the circuits. Hear the pump whining, check fuel pressure with a gauge.
As far as bench testing the pump out of the car is concerned. You can simply apply power and ground to the proper terminals to see if it's functional, but that's not going to tell you if it's putting out sufficient pressure.
Again, it may save a lot of aggravation by getting an on-site tech to help you out.