Proof these, and provided they are in working condition, then replace the fuel pump.
Electric Fuel Pumps
If the engine fails to start on a car with an electric fuel pump, there are numerous points on the electric fuel-pump circuit to check before determining if the fuel pump needs to be replaced. First, place a fuel-pump pressure-and-flow tester at the carburetor inlet fitting and loosen the clamp on the fuel hose connected to the calibrated bottle. Inside the pump is a Supple diaphragm, which is forced in one order by what is called linkage to dream up the compelling suction, while at the twin bout a spring is compressed under the diaphragm. When the linkage relaxes the spring pushes the diaphragm in the antithetical progression and the fuel is pushed outside of the fuel pump.Vapor Lock
The biggest hot potato that occurs with mechanical fuel pumps is vapour lock. When a vehivle engine is shut off, the strength spring in the fuel pump maintains energy in the wrinkle between the pump and carburettor. The heat that would chalk up been dissipated by the radiator comes into the engine compartment in that the coolant has stopped circulating. This heat expands the Gauze in the border between the fuel pump and carburettor. When the expanding petrol tries to receive back into the fuel pump, it is blocked by the Issue valve. The coercion keeps building, pushing the bodkin valve unlatched, filling the float bowl to overflowing and flooding the engine. A bleed gap in the fuel pump Testament dissipate the power. This gap may be installed in Everyone pump valve or the pump casing.
Beyond Vapor Lock
Provided the engine fails to begin and vapour lock is not the consideration, then the fuel pump needs to be tested to good buy the causation of the failure. Install a energy gauge in the carburettor inlet becoming. With the engine operating at indolent velocity, the fuel pump energy indicated on the gauge should Identical the manufacturer's specifications. Insufficient fuel-pump flow could be caused by a restricted fuel column or filter.There are two types of fuel pumps, mechanical and electric. Electric pumps are very broken into four types: plunger, diaphragm, bellows and impeller. A fuel pump draws up fuel down an inlet valve and then pushes it gone to the carburettor.
While the engine runs, check the fuel flow into the bottle. If there is fuel flow into the bottle, says Don Knowles in his book "Automotive Fuel, Lubrication and Cooling Systems," then the fuel pump is not the problem. If there is no flow, check for power at the wire connected from the inertia switch with a 12V test light. If the test indicates no power, then either the starter relay, fuse link, inertia switch or connecting wires are defective.
If power is available at the inertia switch, then disconnect the wiring connector at the fuel pump and connect an ohmmeter from the ground wire to a ground on the vehicle chassis. A low reading indicates that the ground wire is acceptable. Next, connect a jumper wire from the battery positive terminal to the fuel pump terminal that is connected to the inertia switch. If the fuel pump fails to run, the pump is defective and needs to be replaced.
