Fuel Pump After-Run System Test (Federal)

Fuel Pump After-Run System Test (Federal)

PRETEST CONDITIONS

1. Battery voltage OK
2. Fuel tank must be 1/4 full minimum.

WARNING: Fuel will be expelled. Use a clean rag to soak up fuel. Do not disconnect any wires that could cause electrical sparks. Do not smoke or work near heaters or other fire hazards. Keep a fire extinguisher handy.

TEST PROCEDURE

Fuel Pump After-run Components:

1. Connect pressure gauge, VAG 1318 using adaptors 1318/1 and 1318/11 (or equivalent fuel pressure gauge) between fuel rail and fuel pressure switch.
2. START engine and let idle.
3. Check fuel pressure it should be:

approx. 36 psi (2.5 bar)

4. Turn ignition switch OFF.
5. Remove harness connector from fuel pressure switch and measure resistance between switch terminals, resistance should be:

0 ohms approx.
if not fuel pressure switch is faulty

Fuel Pump After-run Components:

6. Remove harness connector from ambient temperature switch and connect the terminal (wire) to ground (-) using jumper wire:

radiator cooling fan MUST run
if not ambient temperature switch or cooling fan is faulty


7. Reconnect fuel pressure switch harness connector, (leave ambient temperature switch wire grounded).
8. Turn ignition switch ON briefly then turn switch OFF:

after 2-3 minutes fuel pump MUST run
if not after-run control unit may be faulty

9. Reconnect ambient temperature switch harness connector onto switch:

fuel pump must NOT run
if not ambient temperature switch is faulty

10. Remove harness connector from fuel pressure switch and measure resistance between terminals resistance should be

0 ohms approx.

11. Lower fuel pressure in the fuel rail by slowly bleeding fuel from the pressure gauge connection.

CAUTION: When loosening pressure gauge connection place clean rag around fitting to avoid the risk of being sprayed.

12. Watch pressure gauge and ohm meter, fuel pressure switch must open (infinite ohms) when pressure drops below:

14 psi (1 bar)