B6 - B14 Checking Fuel Pumps, Fuel Pressure and Regulator

B6 Connecting Fuel Pressure Gauge
- Turn ignition OFF





- Hold a piece of absorbent paper underneath fuel line to prevent spillage when line is loosened.
- Connect gauge between fuel line and fuel distribution rail.
- Use hose 5116 and adapter 5265.
- Plug gauge hose with 5266.
- Turn gauge cock to position 1 (pointing towards hose 5116).

B7 Connecting Power to the Fuel Pump Circuit





- Pull out central electrical unit from console and lift out fuel pump relay. (To simplify removal, lift out seat belt reminder as well.)
- Connect a bridge wire across terminals "30" and "87/2".
Both pumps should start. Main fuel pump is easiest to hear.
- To check tank pump, remove fuel tank lid and listen.

B8 If Neither Pump Operates:





- Disconnect bridge wire from terminals "30" and "87/2".
- Check for voltage at terminal "30".
No voltage = check wire between battery and relay.
- Connect a bridge wire across terminals "30" and "87/2" in relay connector.
Both pumps should run.
Pumps do not start = check wires between relay and pumps.
- Check circuit between terminals "87/1" and "85". Use an ohmmeter or test buzzer.
- Check that terminals "86/1" and 86/2" are correctly grounded.
"86/1" will only be grounded when the ignition is on.
"86/2" will only be grounded when the engine is running.
- Grounds incorrect = check wiring harness to control unit.
- Test with a new relay.

B9 Checking Fuel Pressure
If Both Pumps Operates:
- Check Fuel Pressure
Fuel pressure = 250 kPa (36 psi).

B10 If Fuel Pressure Is Too High:
- Disconnect wire connected between fuel pump relay connections "30" and "87/2".





- Disconnect fuel return line from pressure regulator. Blow through line.
- Disconnect vacuum hose from pressure regulator. Blow through line.
If both hoses are free from blockages, regulator is defective and should be replaced.
- Re-check pressure after installing new regulator.

B11 If Fuel Pressure Is Too Low:





- Pinch fuel return line with hand and check pressure increase.

IMPORTANT Do not allow pressure to exceed 600 kPa (85 psi).

If pressure rises quickly, pumps and fuel lines are OK.
- Replace regulator and measure again.

If pressure rises slowly, this indicates a blocked fuel filter, tank pump filter or fuel line.
- Check and replace as necessary, filters and lines.

If pressure does not rise, fuel pump is defective.
- Replace fuel pump.

B12 Checking Pressure Regulator





- Connect vacuum pump to regulator. Use vacuum pump 5843, or equivalent.
- Pump air out of regulator and check that fuel pressure drops.
Fuel pressure should drop to same extent as vacuum applied to regulator.
^ 250 kPa (36 psi) - vacuum = Fuel pressure.

B13 Switch Off Fuel Pumps





- Disconnect wire between terminals "30" and "87/2".
- Reinstall the relay.





B14 Disconnect pressure gauge 5011
- Hold a piece of absorbent paper underneath fuel line to prevent spillage.

IMPORTANT! Any plastic fuel line ties removed must be refitted.