O.K. I posted with this fuel supply problem before. I thought I had it solved with the solenoid relay, but no dice. This is my 1995 diesel dodge truck. After it still wouldn't start I took the fuel line off the top of the pump that is in the tank and turned the key to the battery. It wasn't pumping any fuel. So I figured it was the pump. As I am waiting for the pump to show up I tested the wires on the top that plug into the cover to the whole assembly. I turned the key to batt again and none of the wires that supply power to the pump had 12volts. What could it possibly be? I am all out of ideas and would love some from anyone!

 

The fuel transfer pump is located on the left side of the engine and above the starter motor Fuel Transfer Pump Location

An improperly operating fuel transfer pump can cause low engine power, excessive white smoke and/or hard engine starting.

Before performing pump pressure testing, inspect the fuel supply and return lines for restrictions, kinks or leaks.

Fuel leaking from the weep hole in the pump casing indicates a leaking pump. The transfer pump must then be replaced.

Low transfer pump output can be caused by a worn eccentric (cam lobe) on the engine camshaft.

In addition to contaminants or air, restrictions in the fuel supply to the injection pump caused by a clogged or dirty fuel filter can cause problems. This may be: low power, poor starting or excessive white smoke. A restricted pre-filter screen within the fuel heater may also have the same results. Refer toLubrication and Maintenance at the front of this manual for recommended filter replacement intervals in time or mileage. Be sure to clean the pre-filter each time the fuel filter is replaced. Refer to Fuel Heater Removal/Installation for pre-filter service procedures.

OUTPUT PRESSURE TEST
Place a drain pan below injection pump.
Remove banjo bolt and gaskets from fuel inlet line fitting at side of injection pump Fuel Inlet Line at Injection Pump
Install Special Tool 6976 and tool gaskets from tool kit 6977 in place of the banjo bolt Checking Fuel Pump Pressure Tighten tool into injection pump.
Install a 0-60 or 0-100 psi fuel pressure gauge to adapter tool 6976 Checking Fuel Pump Pressure
Start and warm engine and record fuel pressure. Pressure should be 117 - 152 kPa (17 - 22 psi) at idle speed. Pressure of 172 - 207 kPa (25 - 30 psi) should be seen after raising engine speed to its rated rpm (2,500 rpm) with no load.
If fuel pressure falls below specifications, do not automatically condemn the transfer pump. The fuel filter or pre-filter may be dirty or clogged. If either of the filters are at fault, the pressure reading will rise after servicing. Recheck fuel pressure after servicing filters.
If pressure is still low, the overflow valve (pressure relief valve) Overflow Valve Location may be defective. To determine if the overflow valve is causing the low pressure condition:
Carefully pinch off fuel return hose at rear of engine Pinching Off Fuel Return Hose
If pressure goes back up to normal or above, the overflow valve must be replaced. Before condemning the valve, make sure it is located (has been installed) at the fuel return line (pump outlet) and not at the fuel supply line (pump inlet)
If pressure remains low with return line pinched, the fuel filter or pre-filter may be restricted or the fuel transfer pump may be defective.
If filters are in good condition and pressure is still low, replace the fuel transfer pump.
After testing, install banjo fitting bolt into fuel supply line and tighten to 24 N·m (18 ft. lbs.) torque.
FUEL VOLUME TEST
Fuel volume-versus-engine cranking rpm are used for the test.

 

O.K. this has you starting the engine to check and mine won't start at all. I have replaced the fuel filter also. Would this cause no power to the pump in the tank?

 

You stated that the truck in question is a '95, is this correct? If so, there is no pump in the fuel tank, and the lift pump is mechanical. It runs on a pushrod from a lobe on the camshaft. You would need to spin the motor over to check for fuel pressure. HTH

 

Really no pump in the tank? What is that whole assembly in there?

 

Just the fuel level sensor and strainer for the pickup.

The lift pump is shown above in the illustration, by pushing the primer button ( black button ) you can fill the filter and pressurize the system.

Electric pumps did not come into play until the 24V, and even then they weren't in tank.

 

Take the rubber line off your LP and crank the motor....See if fuel is being pumped...From the LP..