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R33 Misfire, Just Changed Exhaust

Guest Rotary20B

By Guest Rotary20B,
in Engines & Forced Induction

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Guest Rotary20B

Guest Rotary20B

Posted
Posted

Just changed cat to a high flow magic, and a trust cat back exhaust.

Now up around 5-5500 rpm the car will always misfire, only happens at high rpm, would it be because it is running too rich?

This is the only mods the car has apart from a pod, it never did this before the exhaust change.

Any ideas? I did reset the ecu as well.

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https://www.sau.com.au/forums/topic/130080-r33-misfire-just-changed-exhaust/
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12DFY Collaborator

12DFY

Posted
Posted

Hey mate, because you have upgraded your exhaust the car will actually boost more, the problem you mention sounds like youre spark plug gap needs to be reduced to cater for the increase in air going through youre motor. Drop plug gaps down to about 0.8mm, should solve youre problems.

Bigger exhaust = more air out, which means more air has to go in ;)

  • 2 weeks later...
Guest Rotary20B

Guest Rotary20B

Posted
Posted

Well I changed plugs, bought a new set of copper plugs and regapped them to .8

I didn't want to tape the coils as I couldn't see any cracks at all.

It worked fine on stock boost, then last week I fitted the turbotech boost controller, 10 psi and it would misfire, turned it back down to 7psi and no misfire.

A week later and now it even misfires at 6psi.

I really couldn't be f**ked playing around with taping coils and would just take the plunged and buy a set of splitfire coils if I knew for sure this would fix the problem, any ideas?

Kennedy Mentor

Kennedy

Posted
Posted
Well I changed plugs, bought a new set of copper plugs and regapped them to .8

I didn't want to tape the coils as I couldn't see any cracks at all.

It worked fine on stock boost, then last week I fitted the turbotech boost controller, 10 psi and it would misfire, turned it back down to 7psi and no misfire.

A week later and now it even misfires at 6psi.

I really couldn't be f**ked playing around with taping coils and would just take the plunged and buy a set of splitfire coils if I knew for sure this would fix the problem, any ideas?

Tape them up now to be sure. It's only an hour job. If it fixes then you will know its definitly cracks in your coils...then you can choose to seal them more permantly with silicon or "just buy splitfires". $5 Vs $550.

Same thing happened to me and I could not see any cracks at all...but apprantly they were there coz silicon fixed it.

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