Chevy

Hi all ...any ford techs out here... i had a windstar in the shop few weeks
ago , running on 5 cylinders , no spark on one cylinder (3.8 lite engine )..
but PC wouldn't set a missfire code , customer said its been like that for
over 2 months , he fiduard it was do to having over 260,000 miles , but i
found a bad plug wire on one cylinder ...so my question is why didn't the
pc pick up the missfire and set a code ? what triggers a missfire code , i
thought it was off the crank sensor , seeing RPM decrease ...when it
should be an increase .... i know fords are slower at setting missfire codes
than other manufactures but this was 2 months , guy drives alot , other
fords with 4.6 and 5.4 with coil on plug pick up missfire faster with in
minuets long minuets have had them take ove 5 mins to set a code , dodge i
hate to say is way faster , any ideas ?

Jim Warman

Not knowing the year makes a bit more of a guess. I have seen a couple of
Windstars that would not set misfire codes because misfire profile wasn't
learned. You'd have to check the PIDs and see the "MP_LEARN" status. The PCM
learns the progile of the crankshaft trigger wheel to take into account any
manufacturing variations.

The two that I saw would not learn this profile. The cure for these was to
replace the factory ground that runs from the alternator mount to the rad
support with a continuous wire ground strap - the factory strap has a
plastic "box" containing what I assume is a capacitor.


"Chevy" <chevy396@shaw.ca> wrote in message
news:bMTOe.6989$Hk.2278@pd7tw1no...
> Hi all ...any ford techs out here... i had a windstar in the shop few
weeks
> ago , running on 5 cylinders , no spark on one cylinder (3.8 lite
engine )..
> but PC wouldn't set a missfire code , customer said its been like that
for
> over 2 months , he fiduard it was do to having over 260,000 miles , but i
> found a bad plug wire on one cylinder ...so my question is why didn't
the
> pc pick up the missfire and set a code ? what triggers a missfire code , i
> thought it was off the crank sensor , seeing RPM decrease ...when it
> should be an increase .... i know fords are slower at setting missfire
codes
> than other manufactures but this was 2 months , guy drives alot , other
> fords with 4.6 and 5.4 with coil on plug pick up missfire faster with in
> minuets long minuets have had them take ove 5 mins to set a code , dodge
i
> hate to say is way faster , any ideas ?
>
>

Chevy

well thanks Jim , year i don't remember , 97-99 , once i find the mp
learn , can it be reset from scan tool ?..or just go and check the ground
strap as you mentioned ... doubt i'll see this van again , he was trying to
sell it ..
Thanks or your advice

"Jim Warman" <mechanic@tenalpsulet.net> wrote in message
news:Lv_Oe.195049$9A2.188645@edtnps89...
> Not knowing the year makes a bit more of a guess. I have seen a couple of
> Windstars that would not set misfire codes because misfire profile wasn't
> learned. You'd have to check the PIDs and see the "MP_LEARN" status. The
> PCM
> learns the progile of the crankshaft trigger wheel to take into account
> any
> manufacturing variations.
>
> The two that I saw would not learn this profile. The cure for these was to
> replace the factory ground that runs from the alternator mount to the rad
> support with a continuous wire ground strap - the factory strap has a
> plastic "box" containing what I assume is a capacitor.
>
>
> "Chevy" <chevy396@shaw.ca> wrote in message
> news:bMTOe.6989$Hk.2278@pd7tw1no...
>> Hi all ...any ford techs out here... i had a windstar in the shop few
> weeks
>> ago , running on 5 cylinders , no spark on one cylinder (3.8 lite
> engine )..
>> but PC wouldn't set a missfire code , customer said its been like that
> for
>> over 2 months , he fiduard it was do to having over 260,000 miles , but
>> i
>> found a bad plug wire on one cylinder ...so my question is why didn't
> the
>> pc pick up the missfire and set a code ? what triggers a missfire code ,
>> i
>> thought it was off the crank sensor , seeing RPM decrease ...when it
>> should be an increase .... i know fords are slower at setting missfire
> codes
>> than other manufactures but this was 2 months , guy drives alot , other
>> fords with 4.6 and 5.4 with coil on plug pick up missfire faster with
>> in
>> minuets long minuets have had them take ove 5 mins to set a code , dodge
> i
>> hate to say is way faster , any ideas ?
>>
>>
>
>