Expedition 4WD V8-5.4L SOHC VIN 5 (2005)
THE IGNITION AND FUEL SYSTEMS WITH WDS.
SERVICE PROCEDURE 1:
1.
Retrieve DTCs and record on repair order.
2.
Perform a thorough underhood inspection. If visible concerns are found (wiring, connectors, etc), repair as necessary following normal repair
procedures. Proceed to Step 3.
3.
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 4.
b.
If Power Balance does not indicate a weak cylinder proceed to Step 5.
4.
Perform a Relative Compression test with WDS to determine if a base engine concern is contributing to the weak cylinder(s) identified in Step 3.
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. Do not continue with this TSB.
b.
If Relative Compression test or dry compression test do not show any issues, proceed to Step 5.
5.
Run ignition tests with WDS.
a.
If ignition test indicates a concern, follow normal diagnostics to repair. Proceed to Step 6.
b.
If ignition test does not indicate a concern, remove all spark plugs and inspect for wetness and/or carbon fouling. Record the location of
affected cylinders. Proceed to Step 6.
6.
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 7.
NOTE
IF THE FUEL PRESSURE & LEAKDOWN TEST FAILS, WDS WILL NOT ALLOW THE RELATIVE INJECTOR FLOW TEST TO BE
PERFORMED. IF THIS OCCURS, REPLACE INJECTOR(S) ON CYLINDER(S) THAT HAD WET/FOULED PLUG(S) IN STEP 5B.
PROCEED TO STEP 7.
7.
Replace the spark plug(s) that were fouled. Pre-lubricate any cylinders that had fuel present with two (2) shots of clean engine oil. Do not
over-lubricate cylinders. Proceed to Step 8.
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.
8.
Change oil and filter and clear DTCs. Proceed to Step 9.
9.
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.
SERVICE PROCEDURE 2:
NOTE
ONLY PERFORM SERVICE PROCEDURE 2 IF DIRECTED TO BY THE CAUTION AT THE BEGINNING OF THIS TSB.
1.
Retrieve DTCs and record on repair order.
2.
Remove all spark plugs to determine if fuel is present in cylinder(s).
a.
Inspect spark plugs for wetness and/or carbon fouling and record the location of affected cylinders. Proceed to Step 2b or 2c.
