Changing injector size/ voltage compensation on existing tune

[Liam]

Hi all,

I've been having a look through a calibration on a friend's K20A2 with ITBs, Drag Cartel DICs, and 410cc injectors. The car was recently tuned and runs great when warm, but from cold the car struggles to start without a lot of cranking/ throttle and has a very low idle when it does start. The car often cuts out when cold too unless you hold the throttle.

I've noticed in the calibration that the injector size has been incorrectly set to 630cc when the injectors are in fact 410cc. The voltage compensation is also not correct for the injectors (I believe people use the RDX 440cc dead time for the 410cc injectors). I've read in the documentation that changing the injector size automatically compensates the fuel tables, but is it likely to undo any of the work done by the tuner so far in the fuel tables and throw the fuelling out?

Is correcting the injector size likely to help the starting/ poor running when cold?

We have also found that changing the warm idle speed value in the calibration has no effect. It currently idles around 750-800 RPM when warm when the idle speed in the calibration was 1100 RPM. We increased this to 1600 RPM and idle didn't change.

Many thanks

[Spunkster]

YOu should reset the injector size, then enter the correct dead times and re-tune as needed.

[fonzeka]

Does it still have an idle air control valve?
Otherwise you can only adjust the idle by setting the throttles slightly open, if you want cold idle around 1000rpm your hot idle will be much higher.