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Hunting Idle on a Cold Start


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I notice the idle ign control is bouncing on and off but I think that is more a consequence rather than a cause of the problem.  Still you could try increasing the RPM lockout to see if that settles anything.

What I think is more likely the problem is its initially too lean.  Even though your lambda shows 0.85-0.9, the engine seems happier when it sways closer to 0.85, the manifold vacuum increases etc.  Because ethanol has a much lower vapour pressure, you need a much higher volume of fuel to get enough vapour effect when the port walls are cold etc.  As a test try setting one axis of your lambda target overlay table to charge temp and put something like -0.05 in the cells at low charge temps, see if that helps.


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