Coil on plug : routine maintenance ?

[Robert Myers]

They've been in there for ~3 years.   Not too bad service, IMO.


At 12:47 PM 1/30/2009, Louis-Alain Richard wrote:
> >From my limited experience, this behavior (bad coils at high boost/high
>load) is common to numerous coil-over-plug engines. So maybe replacing these
>is indeed only good practice / routine maintenance ? I've changed coils on
>numerous engines, but never a firewall mounted round coil. Could it be that
>heat and vibration cause accelerated destruction ?
>
>Louis-Alain
>
>
>-----Message d'origine-----
>
>Hi Y'all,
>
>Perhaps you might recall Miss Piggy's Miss.  Well, she had a bad coil
>pack, identified as #3.  Replaced said #3 coil and the pig fired
>right up.  The miss at idle was gone but when trying a high boost run
>there was yet another miss at boost.  Hmmm...  Second bad coil?  I
>ordered a couple of new coils and lived with it for a few days.  A
>couple of days later the pig quit on me just as I drove into my
>driveway and pulled up to the garage.  Oh sh**, err... oh, nuts.  Now
>what?  She's dead, Jim.  I ran her on into the garage using the
>starter motor and just walked away for a while.  Think about it, Bob,
>what had you been doing which might possibly cause this.  Sleep on
>it.  About 3 AM it hit me that I had disconnected the two white B+
>connectors on the firewall a few days earlier.  Maybe one or both
>didn't get back together tightly enough and had worked their way
>apart.  Next morning I disconnected and reconnected the white
>plugs.  Bingo!  Miss Piggy fired right up again.  She has been
>resurrected from what appeared to be a rather severe case of death.
>
>OK, now I finally started miss diagnostics again.  Uh, that's
>diagnosing the miss not mis-diagnosing the problem.  I hope.  When I
>replaced coil #4 and drove the pig snot out of her the miss that I
>had been searching for went away.  Oh goodie.  Now for a REAL
>run.  WOT and _REAL_ boost.  The full time miss is still gone.  The
>miss under low boost is still gone.  BUT - when I finally got her
>running well enough to really develop some boost there is yet another
>even weaker miss which didn't even show up until I'm looking at 26 to
>28 psig.  WTF another weak coil?  I think so.  I have ordered even
>more coils and will replace the rest of the old coils.  I think that
>will finally get the pig running well again and give me a few more
>spare coils for my Rosattobin.
>
>So, Miss Piggy is feeling much better now.  I'll see about the other
>coils in a few days.
>
>The moral to this little story?  Don't count your pigs until the
>chicken crosses the road or something like that.
>
>Bob
>
>
>
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