The cold start working/not working shouldn't be a result of the ecu being an ipd modified unit. The mods done to the boxes didn't intrude on any of the cold start circuits.

So - if your CS injector doesn't work, it's more likely that something's amiss with the CS injector itself, its relay, or the wiring connecting the two. Very doubtful that it has anything to do with the ecu.

Last but not least - you shouldn't have to do anything to richen the mixture when starting the engine cold. The CS injector only squirts when the starter is engaged anyway, so its role is really pretty minor. My last Djet car never has a CS injector nor an aux air valve and it started reliably even down to temps below zero.

Best,

Cameron
Rose City