The V8 Owners Forum -

I have a fitted, running and mapped ms2 system on my Tvr Chimaera.
I'm tweaking some settings for cold start.
Stepper control is a little erratic, I've confirmed it's movement in the iac test section and am happy it's open and closed.
My question relates to the base idle, which used to be set at roughly 600 rpm with bypass hose clamped on the Tvr.
Do I do the same thing on megasquirt?
At the moment if I clamp the hose the engine stalls so I'm thinking there isn't enough bypass air to accurately adjust the stepper values.
I see people commenting they set a base idle of 800 rpm on the megasquirt first but is this done with the throttle stop screw or bypass air screw?
Thanks in advance.

My guess would be:-

1. Set the throttle stop so the butterfly is just cracking open. (0.004", 0.1mm)
2. With the stepper motor close, set the idle sped to 600rpm with the bypass screw. (Best to use the Tuner Studio tach for this)
3. Set the required idle speed with Tuner Studio.

Thanks, I have set the throttle disc open very slightly about quarter of a turn on the stop screw but i will check the clearance inside.