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Misfire under load - rebuilding coil packs

phatmonk

By phatmonk,
in General Maintenance

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phatmonk Enthusiast

phatmonk

Posted
Posted (edited)

Hi,

I started a thread not long ago about misfiring under medium to heavy acceleration.  Poking around I had really odd results testing the resistance on the coil pack ignitor.  It lead me to believe the ignitor was faulty; replaced this and the problem didn't go away.  I'm still curious what the resistance of other ignitors are... when I get a multimeter I'll test the re-furb unit too.

In short, here is what i did:

  • Replaced the ignitor - same.
  • Dropped in a set of BCPR6ES-11 - same
  • Dropped in a set of BCPR6ES - better but still same same
  • Checked for un-metered air.  Found K&N oil from the panel in the air box.  Replaced with paper filter, cleaned AFMs with CRC AFM cleaner - marginally better with the BCPR6ES in there.

Inspected the coil packs.  No cracking.  Did some reading about coil packs and had a penny drop moment.  Basically, two things:

  1. The coils packs, as in the induction coils in the unit itself generally work, or don't.  Rule of thumb, there are examples of them failing but not for this post.  So, in my case the coil pack fires, and it works.
  2. It's the plastics around the pack that break down.  Sometimes visibly, other times not.

Stumbled onto a YouTube video: https://www.youtube.com/watch?v=Qirx_G4x5i0  Guy with an Aussie accent.  I'd be shocked if he isn't on SAU.  If you are out there and read this, chime in and take credit.

Bought a second hand set of coil packs, some contact cleaner and 2x 7g tubes of dielectric grease.  Pulled the coil packs out and apart, sprayed everything with contact cleaner.  Then a generous ring of dielectric grease around where the pack flanges out and also underneath the flange.  Put the clean springs back in, slid the plastic part nozzle on with another run of dielectric grease around the base.  To be sure.  Could have been done easily with one tube but being super generous and ended up using a tiny part of the second tube.

On the first drive, oh my!  How different the car feels.  Smoother acceleration, less backfiring from the exhaust, better (smoother?) engine sound and no misfiring.

Looking at the old coil packs.  See the below pictures.  The rim has oxidized, the springs are dirty (pics don't show it) and inside the coil are black marks...

If the OEM coils are as good as anything aftermarket, I'd spend the $30 on parts and in an hour it'll be like new.  A run of dielectric grease is on my maintenance list whenever I do plugs.

HTH someone else.

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Edited by phatmonk
Early post. That's what she said.
  • Like 2
TMLP Community Regular

TMLP

Posted
Posted

Your absolutely right but I still took the opportunity to tell the Aussie wife they were faulty & replaced all six with new splitfies & the contacts cleaned & the dielectric grease. It too brought awesome results.

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