Expedition 4WD V8-5.4L SOHC VIN 5 (2005)
b.
If no fuel is present leave spark plugs out and proceed to Step 4.
WARNING
PERFORM STEP 2C IN A WELL VENTILATE AREA AWAY FROM ALL IGNITION SOURCES. HIGHLY FLAMMABLE MIXTURES MAY
BE PRESENT AND COULD BE IGNITED. FAILURE TO FOLLOW THIS WARNING MAY RESULT IN PERSONAL INJURY.
c.
If fuel is present, remove fuel from cylinder(s) by disconnecting the battery, and turning the engine over by hand, raising the affected piston
to TDC. Use an air hose-blow gun and protective catch rag to remove any remaining fuel. Proceed to Step 3.
3.
Once gasoline is evacuated from cylinder(s), squirt two (2) shots of clean engine oil to re-lubricate cylinder(s) and prevent piston scuff. Do not
over-lubricate cylinders. Proceed to Step 4.
4.
With the spark plugs removed, perform Fuel Pressure & Leakdown test and Relative Injector Flow test with WDS. If an injector fails the Relative
Flow Test, and/or was on a cylinder with a wet/fouled plug, replace the injector for that cylinder. Proceed to Step 5.
NOTE
IF THE FUEL PRESSURE & LEAKDOWN TEST FAILS, WDS WILL NOT ALLOW THE RELATIVE INJECTOR FLOW TEST TO BE
PERFORMED. IF THIS OCCURS, REPLACE THE INJECTOR(S) ON CYLINDER(S) THAT HAD WET/FOULED PLUGS IN STEP 2A.
PROCEED TO STEP 5.
5.
Replace the spark plug(s) that were fouled. Proceed to Step 6.
NOTE
IF SPARK PLUG REPLACEMENT IS REQUIRED ON A VEHICLE BUILT BEFORE 4/26/2005, CHECK THE SPARK PLUG PART NUMBER
STAMPED ON THE PLUG. IF SPARK PLUGS MARKED WITH "PZT 1F" ON THE PORCELAIN INSULATOR ARE INSTALLED, ONLY
REPLACE THE FOULED PLUG. IF ANY OTHER SPARK PLUG IS INSTALLED, REPLACE ALL 8 SPARK PLUGS WITH THE PZT 1F-F4
PLUGS. DO NOT INTERMIX PZT 1F-F4 AND PZT 2F-F4 PLUGS.
6.
Change the engine oil and filter. Proceed to Step 7.
NOTE
EVEN THOUGH THE ROOT CAUSE OF THE CONDITION MAY HAVE BEEN ELIMINATED IN STEPS 1-6, CONTINUE WITH ALL
REMAINING STEPS OF TSB TO CONFIRM THERE ARE NO REMAINING IGNITION OR BASE ENGINE ISSUES.
7.
Perform a thorough underhood inspection. If visible concerns are found (wiring, connectors, etc), repair as necessary following normal repair
procedures. Proceed to Step 8.
8.
Perform a Power Balance test with WDS to confirm or identify weak cylinder(s).
a.
If Power Balance indicates a weak cylinder proceed to Step 9.
b.
If Power Balance does not indicate a weak cylinder proceed to Step 10.
9.
Perform a Relative Compression test with WDS to determine if a base engine concern is contributing to the weak cylinder(s) identified in Step 8.
a.
If Relative Compression test indicates a low cylinder, confirm base engine concern by performing a dry compression test using a
compression gauge with all plugs removed and battery condition at 100%. If low compression is confirmed, follow normal Workshop
Manual diagnostics for base engine repair.
b.
If Relative Compression test or dry compression test do not show any issues, proceed to Step 10.
10.
Run ignition tests with WDS.
a.
If ignition test indicates an issue, follow normal diagnostics to repair the concern, then proceed to Step 11.
b.
If ignition test does not indicate any issues, proceed to Step 11.
11.
Clear DTCs. Drive vehicle at highway speed and bring engine to full operating temperature for a minimum of 10 minutes to clear any excess fuel
from the catalytic converters. Monitor the front and rear heated exhaust oxygen sensor (H025) switching rates, to determine catalyst condition.
Normal switching frequency of the post-catalyst H025 should be very slow with reduced amplitude as compared to the switching frequency and
amplitude of the pre-catalyst H025. Refer to PC/ED, "Catalyst Efficiency Monitor and Exhaust Systems" for an overview of the catalyst efficiency
monitor. Follow Pinpoint test HF if needed. Recheck for DTCs and follow normal diagnostics if necessary.
