[Diy_efi] Iridium plug problems

[Tim Marsteiner]

These are the plugs pulled this morning:

http://www.superxtune.com/images/plugs.JPG

I am running LOP (tuned about 16.0:1) at cruise engine
loads and data logs of narrow band O2 sensor show
0.000 volts right before the problem starts.

Hmmm ... how about this scenario, fuel pressure drops
drastically, mixture is too lean to fire consistently,
some unburned mixture left in exhaust and/or chamber
finally does ignite causing severe backfiring and
possibly some light detonation.

Fuel pump/pressure regulator is inside tank but sits
inches above the front cylinder head... definitely
could be affected by heat soak.


Tim


--- Rod Hiorns <R.E.Hiorns at IEE.org> wrote:

> It's the cylinder pressure, the spark gap, and the
> sharpness of the
> electrodes that determine the strike voltage, and
> it's higher voltages
> that punch through the insulation of the coils (and
> leads where applicable)
> sooner than lower ones. Unless you've opened your
> gap, or rounded your
> electrode I think your iridiums will put *less*
> stress on your COPS.
> 
> I'd suggest you have mixture issues which could be
> fouling the plug as
> you go through warm-up. What pressure's the rail and
> is it supplying
> evenly?
> 
> HTH
> Rod



		
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