----- Original Message -----
Sent: Monday, July 11, 2005 8:49 PM
Subject: TROUBLESHOOTING FORD COIL PACKS
> Is there any way to check coil packs on a 2000 Ford Crown Vic? I have a
> mis fire on a cylinder (or maybe two) and if the pack is good I may
> just need a new boot, (if they sell only the boot) I did have the same
> problem a year ago and the dealer replaced two packs under warranty,
> now Ford wants some big $$$ to check out the car and about $250 per
> coil pack. At these prices I should replace all remaining 6 at $80
> each. Any Ideas??? What is the best way to find out which coil pack is
> giving me the problem, the check engine light is not on.
If the check engine light is not on, why do you think you have a misfire? It
has been my experience that the OBDII system is very good at detecting
misfires. Ford Issued a TSB warning dealers that 50% of the coil pack being
replaced under warranty were not bad. The TSB included elaborate tests for
determining whether or not a coil pack is bad. The tests don't look like
something you can do at home. If you have a misfire, the OBDII code will
identify the cylinder with the misfire. The boots are separately replaceable
(they cost $3 to $5). The dealer should sell you a coil pack (uninstalled)
for around $100. Aftermarket coil packs are available for less than $75.
Lazy mechanics often blame coil packs when they are not at fault. Dishonest
mechanics often blame the coil packs because they are profitable to replace.
Are you sure you don't have an intake manifold leak or other problem?
Here is part of the Ford TSB:
Approximately 50% of coil on plug (COP) coils returned for warranty do not
have a problem.
The misfiring cylinder must be identified through Self-Test misfire codes or
through WDS Power Balance. Rule out base engine problems, rule out fuel
problems, and then look at ignition problems (be sure to rule out coil
primary circuit issues). Once the above steps have been completed, and the
issue is in the secondary part of the ignition system, the oscilloscope
procedure outlined in this TSB can isolate the difference between a coil or
spark plug problem.
The optional WDS COP Kit available through Rotunda will provide more
accurate diagnosis and help reduce replacement of non-defective parts. The
Kit (418-FS528) can be purchased through 1-800-ROTUNDA.
The following material will detail the diagnostic steps on WDS to take the
guesswork out of misfire diagnosis using the COP Kit. The following
procedure is for cylinder specific misfires and not random misfires. Random
misfires have a different root cause and are not covered by this TSB.
A misfiring cylinder is lacking power relative to the other cylinders. The
causes for a cylinder specific misfire could be fuel, spark, or mechanical
problems. Perform a thorough visual inspection. If no visible concerns are
found use the following WDS tools for misfire diagnosis:
^Self-test (Check for codes first)
^Power Balance (Identify the cylinder of concern)
^Relative Compression (Rule out a possible mechanical issue)
^Fuel (Make sure fuel injectors are not restricted)
^Ignition (Make sure spark plugs and coils are working properly)
Oscilloscope (Detailed signal analysis)
NOTE USE THE ENCYCLOPEDIA BUTTON IN THE LOWER LEFT CORNER OF THE SCREEN FOR
DETAILED INFORMATION ON THE WDS TOOL BEING DISPLAYED.
If there is a self-test code identifying a particular cylinder then you just
need to determine if it is a fuel, ignition, or possibly a mechanical
problem. Proceed to Step 2 after running Relative Compression to rule out
any mechanical issues. If there is no self-test code and the customer
concern is a miss, proceed to Step 1.......
Ed >> Stay informed about: TROUBLESHOOTING FORD COIL PACKS