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Engine Controls - System & Component Testing: Diagnosis Infiniti G20 II

Testing & Diagnostics 6 illustrations ~379 words

EVAP System Leak Test

CAUTIONDO NOT use compressed air. DO NOT start engine. DO NOT apply more than.6 psi (4.12 kPa) of pressure to EVAP system.

Using EVAP Service Port Adapter (J41413-OBD), connect suitable pressure pump with gauge to EVAP service port. See VACUUM DIAGRAMS article for location. Disconnect EVAP Canister Vent Control Valve (EVAP-CVCV) and vacuum cut valve by-pass valve harness connectors. (Scheme 40)or (Scheme 41). Using jumper wires, apply battery voltage to EVAP-CVCV and Vacuum cut valve by-pass valve terminals. Apply.2-.4 psi (1.38-2.76 kPa) of pressure to EVAP service port. Remove pressure pump from EVAP service port. Using Leak Detector (J41416), locate EVAP system leak.

Scheme 40

Scheme 40
Scheme 40

Scheme 41

Scheme 41
Scheme 41

EVAP Canister Test

Remove EVAP canister. Plug vent hose and blow air into port "A". Air should flow freely out of port "B". (Scheme 42) Replace EVAP canister if operation is not as specified.

Scheme 42

Scheme 42: EVAP Canister Test
Scheme 42: EVAP Canister Test

Refueling Control Valve Test

  1. Remove fuel filler cap. Disconnect signal line hose from fuel filler tube. Disconnect refueling EVAP vapor line hose from tube. (Scheme 43)or (Scheme 44).
  2. Leave both hoses connected to fuel tank. Blow air into refueling EVAP vapor line hose. Air should flow freely into fuel tank. Blow air into signal line hose. Air should not flow. Using a hand pressure pump with a "T", apply 2.9 psi (20.0 kPa) of pressure to both hoses. (Scheme 45) Air should not leak. If operation is as specified, refueling control valve is okay. If operation is not as specified, replace fuel tank.

Scheme 43

Scheme 43
Scheme 43

Scheme 44

Scheme 44
Scheme 44

Scheme 45

Scheme 45
Scheme 45

Refueling EVAP Vapor Cut Valve Test

  1. Remove fuel tank. Remove fuel level sensor unit retainer. Drain fuel from tank using a hand pump. To check if refueling EVAP vapor cut valve is stuck closed, blow air into refueling EVAP vapor line. (Scheme 45) If air flows freely into fuel tank, go to next step. If air does not flow freely into fuel tank, replace fuel tank.
  2. To check if refueling EVAP vapor cut valve is stuck open, connect a vacuum pump with a "T" to signal line and refueling EVAP vapor line. (Scheme 45) Remove fuel gauge/fuel level sensor unit. Invert fuel tank. Apply 3.94 in. Hg (13.3 kPa) of vacuum to signal line and refueling EVAP vapor line. If vacuum does not hold, replace fuel tank. If vacuum holds, refueling EVAP vapor cut valve is okay.

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