Hunting Idle on a Cold Start

[lostsoul]

Can someone take a look at my Cold Start ... The engine speed osculates up and down for the first 40 sec or so on a cold start.

Thanks in advance.

TPS Fuel Table Load DEFAULT Cold start un altered.pclr

Cold start.llg

[Adamw]

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.

 

[lostsoul]

Had a play with things as per your suggestions and a few other thoughts I had. Not looking to bad now ? Using a screen shot of the 1st 30 -40 sec  as the log file was a fraction too big.