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Home >> Mercury >> 1997 >> Tracer L4-122 2.0L SOHC >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Testing and Inspection >> Pinpoint Tests >> HW - Evaporative Emission (EVAP) - Purge Flow System >> HW11 - HW20

HW11 - HW20




HW11 - Check EVAP Canister

- Disconnect fuel vapor hose to EVAP canister purge valve at EVAP canister.
- Check for contamination or blockages at all ports on EVAP canister (to the fuel tank, to the EVAP canister purge valve and to the atmosphere).

Is a fault indicated?

YES REPAIR EVAP canister. RESTORE vehicle. If components are replaced, GO to HW42. HW41 - HW43
NO GO to HW12.

HW12 - Check For Fuel Vapor Hose Leak Between EVAP Canister Purge Valve And EVAP Canister

- Disconnect other end of fuel vapor hose from EVAP canister at EVAP canister purge valve.
- Plug open end of fuel vapor hose at EVAP canister.
- Install a hand vacuum pump to open end of fuel vapor hose at EVAP canister purge valve.
- Apply 53 kPa (16 in-Hg) of vacuum with vacuum pump.

Does the vacuum pump hold the vacuum?

YES REMOVE plug in hose. GO to HW13.
NO REPLACE damaged fuel vapor hose. RESTORE vehicle. GO to HW42. HW41 - HW43

HW13 - Check For Fuel Vapor Hose Blockage Between EVAP Canister Purge Valve And EVAP Canister

- Disconnect other end of fuel vapor hose from EVAP canister at EVAP canister purge valve.
- Install a hand vacuum pump to open end of fuel vapor hose at EVAP canister purge valve.
- Apply 53 kPa (16 in-Hg) of vacuum with vacuum pump.

Does the vacuum pump hold the vacuum?

YES REMOVE vacuum pump. REPAIR or STRAIGHTEN fuel vapor hose as necessary. RESTORE vehicle. GO to HW42. HW41 - HW43
NO REMOVE vacuum pump.
For Escort/Tracer, Mustang, Thunderbird/Cougar, Ranger, Aerostar: RECONNECT fuel vapor hose at EVAP canister. LEAVE other end of fuel vapor hose disconnected at EVAP canister purge valve. GO to HW17.
All Others: RECONNECT fuel vapor hose between EVAP canister and EVAP canister purge valve. GO to HW14.

HW14 Check For Filter Contamination Or Damage To The EVAP Canister Purge Valve

- Disconnect vacuum line from input vacuum port to intake manifold on EVAP canister purge valve.
- Install a hand vacuum pump to input vacuum port on EVAP canister purge valve.
- Apply 48-52 kPa (10-15 in-Hg) of vacuum to EVAP canister purge valve.

Does the EVAP canister purge valve hold vacuum or show a very slow release of vacuum to atmosphere?

YES REPAIR EVAP canister purge valve filter blockage or REPLACE EVAP canister purge valve. RESTORE vehicle. GO to HW42. HW41 - HW43
NO REMOVE vacuum pump. GO to HW15.

HW15 - Check For Intake Manifold Vacuum At VMV: Both Input Port Vacuum Hose And Fuel Vapor Hose

- EVAP canister purge valve electrically connected.
- Disconnect both input port vacuum and fuel vapor hoses from intake manifold vacuum source and fuel vapor ports at EVAP canister purge valve. (Refer to the EVAP canister purge valve vacuum schematic at the beginning of this pinpoint test.)
- Install a vacuum gauge (two gauges or one gauge at a time) to open end of input port vacuum hose and open end of the fuel vapor hose at EVAP canister purge valve.
- Start engine.

Are both vacuum gauge readings greater than 33.77 kPa (10 in-Hg)?

YES LEAVE input port vacuum and fuel vapor hoses to the intake manifold at EVAP canister purge valve disconnected. GO to HW16.
NO ISOLATE causes of missing intake manifold vacuum. REPAIR partially unconnected hoses or kinked/blocked hoses to intake manifold. REMOVE vacuum gauge(s). RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. GO to HW42. HW41 - HW43

HW16 - Check For Input Port Vacuum Hose And Fuel Vapor Hose Restrictions Between Evap Canister Purge Valve And Intake Manifold

- Disconnect input port vacuum hose and fuel vapor hose from EVAP canister purge valve at intake manifold (other end of hoses are already disconnected).
- Install a hand vacuum pump to one end of each completely disconnected hose from EVAP canister purge valve to intake manifold.
- Apply 53 kPa (16 in-Hg) of vacuum with vacuum pump.
- Observe the vacuum reading for 30 seconds.

Does the vacuum bleed oft immediately?

YES REMOVE vacuum pump. CORRECT minor concerns with input vacuum hose and fuel vapor hose between EVAP canister purge valve and intake manifold. If hoses were OK, REPLACE damaged EVAP canister purge valve. RESTORE vehicle. GO to HW42. HW41 - HW43
NO REMOVE vacuum pump. REMOVE blockages or minor kinks in input vacuum hose and fuel vapor hose between EVAP canister purge valve and intake manifold. RESTORE vehicle. DRIVE vehicle. GO to HW42. HW41 - HW43

HW17 Check VPWR Voltage To Evap Canister Purge Valve

- Disconnect EVAP canister purge valve harness connector.
- Key on,engine off.
- Measure VPWR circuit voltage at EVAP canister purge valve harness connector to battery negative post.
- Key off.

Was voltage greater than 10.5 volts?

YES GO to HW18.
NO REPAIR open circuit. RESTORE vehicle. COMPLETE PCM reset to clear DTCs. RERUN Quick Test.

HW18 - Check EVAP Canister Purge Valve Stuck Open Condition Or PF Sensor Damage

- Disconnect fuel vapor hose from intake manifold at PF sensor.
- Reconnect the EVAP canister purge valve (electrically).
- Install a hand-held vacuum pump to intake manifold side of PF sensor.
- Apply 53 kPa (16 in-Hg) of vacuum to open end of PF sensor.

Does the EVAP canister purge valve-PF sensor assembly hold vacuum for 20 seconds?

YES LEAVE the vacuum pump connected. GO to HW19.
NO If PF sensor housing is cracked, REPLACE PF sensor. Otherwise, REPLACE fuel vapor hose between EVAP canister purge valve and PF sensor. If fuel vapor hose was OK, REPLACE EVAP canister purge valve. RESTORE vehicle. GO to HW42. HW41 - HW43

HW19 - Check Hose Blockage - EVAP Canister Purge Valve Stuck Closed Condition

- Connect scan tool.
- Apply 53 kPa (16 in-Hg) of vacuum to open end of PF sensor.
- Key on, engine off.
- Access Output Test Mode on the scan tool to cycle EVAP canister purge valve.
- Key off.

Did the EVAP canister purge valve open and vacuum reading on the vacuum pump drop (air passes freely) when commanding the output on?

YES REMOVE vacuum pump. GO to HW2O.
NO REMOVE the vacuum pump. REMOVE blockages in fuel vapor hose between EVAP canister purge valve and PF sensor. If OK, REPLACE EVAP canister purge valve. RESTORE vehicle. GO to HW42. HW41 - HW43

HW20 - Check Intake Manifold Vacuum To PF Sensor

- Install a vacuum gauge to the open end of fuel vapor hose (intake manifold side) at PF sensor.
- Start engine.
- Observe vacuum gauge at idle (for Escort/Tracer application observe vacuum gauge reading at part throttle).
- Key off.

Was the vacuum gauge reading greater than 33.77 kPa (10 in-Hg) with engine running?

YES CHECK for small vacuum leaks between PF sensor and intake manifold. REPAIR as necessary. RESTORE vehicle. DRIVE vehicle. GO to HW42. HW41 - HW43
NO REMOVE blockage, RECONNECT loose fuel vapor hose or REPLACE cracked, split fuel vapor hose between the PF sensor and intake manifold. GO to HW42. HW41 - HW43
If DTC P1443 is still present, GO to HW21. HW21 - HW30

All others: RETURN to Symptom Charts.
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