Tuning questions -- cold start problems

[Jamesl]

I'm struggling with cold start issues. The other day after much messing about, I got my car to idle fine at about 1200 rpm. It was on a warm day and I had started it enough times that it was probably close to warmed up.
I had set req-fuel at 10 and used MegaTune to generate a VE table... then I jacked req-fuel up to 17 without changing the VE table and it ran fine.

Tonight, with colder weather in the high 40s, I could never get it to idle. It always starts easily enough, but then runs like crud, barely staying alive until it dies.

I've changed afterstart enrichment from 1 to 50 and warmup enrichment from 100 to 150 at all temperature ranges. I also changed req-fuel from 8 to 18.

My problem is, I'm not sure if it's too rich or too lean. The O2 sensor doesn't give me much help. If I hold the throttle open, it will run in the 2k range, but kind of burbbles and doesn't sound happy. 02 readings jump around above 1200 rpm as I open and close the throttle.

Pasted below is a copy of my VE table. Does it seem reasonable?

Any tips?

James

[efahl]

On Wed, December 8, 2004 10:58 pm, Jamesl said:

> Pasted below is a copy of my VE table. Does it seem reasonable?

If you have off-idle stumble, it's usually due to that region
from 500-1500 RPM and 50-100 kPa being too lean. This will make
the engine stumble slightly when warm, but will kill it when cold.
As a first pass, I'd try making that block of cells the same value
as you've got at about 2300-60 = 65% or so and go from there.

--
Eric Fahlgren http://www.not2fast.com/

[Jamesl]

Thanks! I will give that a try.
JamesL