Fuel Pressure: Testing and Inspection

Pressure Test

1. Disconnect fuel line from carburetor and connect a suitable fuel pressure gauge onto line.
2. Disconnect and cap fuel return line from fuel pump.
3. Start and operate engine at idle. Note fuel pressure gauge reading.
4. Fuel pump pressure should be 2.84---4.27 psi. If not, replace fuel pump.

Flow Rate (Volume) Test

1. Disconnect carburetor fuel line and insert end of line into a suitable measuring beaker.
2. Disconnect and plug fuel return line from fuel pump.
3. Start and operate engine at idle and measure fuel pumped into beaker within one minute.
4. If more than 860cc on 626 models, or 800cc on GLC models is pumped into beaker, pump is operating properly. If not, replace fuel pump.