Coil on plug : routine maintenance ?
bob at chips-ur-s.com
Fri Jan 30 09:53:54 PST 2009
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 ?
>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.
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