Thread: 930 misfire
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ficke ficke is offline
Join Date: Nov 2004
Location: Tucson, Az.
Posts: 2,370
Originally Posted by 930cabman View Post
Maybe "misfire" is the incorrect term. The issue occurs when under boost, about .4 atm. I will be rolling along just fine, increase the throttle opening to a point where the turbo kicks in, she pushes ok until it reaches about .4 or .5 atm boost. If I keep my foot into it a rather strong hesitation occurs usually accompanied with a backfire in the intake system.
Given these results I am no longer thinking about the plug wires/plugs.
Is the issue somewhere in the wastgate?
I am currently at a loss. She runs just great until I decide to give her a kick.
It is going lean. If an engine is rich it just does not make as much power and makes black smoke.
When the boost comes on he is getting more air and not the fuel to burn with it and it back fires through the intake, classic lean misfire. There must be something on these cars to enriching the mixture to compensate for boost pressure, I would look into that.
Lean is dangerous and needs to be addressed ASAP.
Rich is not nearly as dangerous and more annoying usually.
It is not a waste gate because that would just affect boost pressure and not fuel mixture. Loss of power or to much.
If it was bad wires he would just have dead cylinders under load and not the back fire.
Of course I could be entirely wrong, just my two cents.
Old 05-21-2012, 07:40 AM
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