NO.14 POOR FUEL ECONOMY[AJ (3.0L Duratec)]

• The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services:

― Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel.

― Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete “BEFORE SERVICE PRECAUTION” and “AFTER SERVICE PRECAUTION” described in this manual.

(See BEFORE SERVICE PRECAUTION[AJ (3.0L Duratec)].)

(See AFTER SERVICE PRECAUTION[AJ (3.0L Duratec)].)

STEP	INSPECTION	RESULTS	ACTION
1	• Inspect the following: ― Air cleaner element for contamination ― ATF level ― Fuel quality ― Coolant level • Are all items normal?	Yes	Go to the next step.
No	Service if necessary. Repeat Step 1.
2	• Connect the M-MDS to the DLC–2. • Turn the ignition switch to the ON position (Engine off). • Retrieve any DTCs. • Is “PASSED” displayed?	Yes	No DTC is displayed: • Go to the next step.
No	DTC is displayed: • Go to the appropriate DTC test.
3	• Access the ECT PID. • Drive vehicle while monitoring PID. • Is the PID within specification?	Yes	Go to the next step.
No	Inspect for coolant leakage. Inspect the cooling fan operation or thermostat operation.
4	• Perform the spark test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION[AJ (3.0L Duratec)]) • Is the strong blue spark visible at each cylinder?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the spark test result.
5	• Inspect for the following ignition control system related parts: ― Spark plug (heat range) ― CMP sensor installation ― CMP sensor trigger wheel damaged (on camshaft) ― Open or short circuit on CMP sensor ― Open or short circuit between CMP sensor and PCM terminal 85 • Are all items normal?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part.
6	• Install the fuel pressure gauge to fuel line. • Start the engine run it at idle. • Measure the fuel line pressure at idle. • Is the fuel line pressure correct? (See FUEL LINE PRESSURE INSPECTION[AJ (3.0L Duratec)].)	Yes	Go to the next step.
No	Zero or low: Inspect the clogged fuel line. • If normal, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION[AJ (3.0L Duratec)].) High: Replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION[AJ (3.0L Duratec)].)
7	• Remove and shake PCV valve. • Does PCV valve rattle?	Yes	Go to the next step.
No	Replace the PCV valve.
8	• Visually inspect the exhaust system part. • Is there any deformed exhaust system part?	Yes	Replace the suspected part.
No	Go to the next step.
9	• Is the brake system functioning properly?	Yes	Go to the next step.
No	Inspect for cause.
10	• Inspect the MAF sensor for contamination. • Is there any contamination?	Yes	Replace the MAF sensor.
No	Go to the next step.
11	• Is the engine compression correct?	Yes	Inspect the valve timing.
No	Inspect for cause.
12	• Verify the test results. ― If normal, return to the diagnostic index to service any additional symptoms. ― If malfunction remains, inspect related Service Information and perform repair or diagnosis. • If vehicle is repaired, troubleshooting completed. • If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.

STEP

INSPECTION

RESULTS

ACTION

• Inspect the following:

― Air cleaner element for contamination

― ATF level

― Fuel quality

― Coolant level

• Are all items normal?

Yes

Go to the next step.

Service if necessary.

Repeat Step 1.

• Connect the M-MDS to the DLC–2.

• Turn the ignition switch to the ON position (Engine off).

• Retrieve any DTCs.

• Is “PASSED” displayed?

Yes

No DTC is displayed:

• Go to the next step.

DTC is displayed:

• Go to the appropriate DTC test.

• Access the ECT PID.

• Drive vehicle while monitoring PID.

• Is the PID within specification?

Yes

Go to the next step.

Inspect for coolant leakage.

Inspect the cooling fan operation or thermostat operation.

• Perform the spark test.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION[AJ (3.0L Duratec)])

• Is the strong blue spark visible at each cylinder?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the spark test result.

• Inspect for the following ignition control system related parts:

― Spark plug (heat range)

― CMP sensor installation

― CMP sensor trigger wheel damaged (on camshaft)

― Open or short circuit on CMP sensor

― Open or short circuit between CMP sensor and PCM terminal 85

• Are all items normal?

Yes

Go to the next step.

Repair or replace the malfunctioning part.

• Install the fuel pressure gauge to fuel line.

• Start the engine run it at idle.

• Measure the fuel line pressure at idle.

• Is the fuel line pressure correct?

(See FUEL LINE PRESSURE INSPECTION[AJ (3.0L Duratec)].)

Yes

Go to the next step.

Zero or low:

Inspect the clogged fuel line.

• If normal, replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION[AJ (3.0L Duratec)].)

High:

Replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION[AJ (3.0L Duratec)].)

• Remove and shake PCV valve.

• Does PCV valve rattle?

Yes

Go to the next step.

Replace the PCV valve.

• Visually inspect the exhaust system part.

• Is there any deformed exhaust system part?

Yes

Replace the suspected part.

Go to the next step.

• Is the brake system functioning properly?

Yes

Go to the next step.

Inspect for cause.

• Inspect the MAF sensor for contamination.

• Is there any contamination?

Yes

Replace the MAF sensor.

Go to the next step.

• Is the engine compression correct?

Yes

Inspect the valve timing.

Inspect for cause.

• Verify the test results.

― If normal, return to the diagnostic index to service any additional symptoms.

― If malfunction remains, inspect related Service Information and perform repair or diagnosis.

• If vehicle is repaired, troubleshooting completed.

• If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.

14	Poor fuel economy
DESCRIPTION	• Fuel economy is unsatisfactory.
POSSIBLE CAUSE	• Contaminated air cleaner element • Engine cooling system malfunction • Improper ATF level • Weak spark • Poor fuel quality • Erratic or no signal from CMP sensor • Improper coolant level • Inadequate fuel pressure • Spark plug malfunction • PCV valve malfunction • Brake dragging • Improper valve timing due to jumping out of timing belt • Contaminated MAF sensor • Improper engine compression • Exhaust system clogging Warning • The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services: ― Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. ― Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete “BEFORE SERVICE PRECAUTION” and “AFTER SERVICE PRECAUTION” described in this manual. (See BEFORE SERVICE PRECAUTION[AJ (3.0L Duratec)].) (See AFTER SERVICE PRECAUTION[AJ (3.0L Duratec)].)