Good day fellow GT-R enthusiasts!
I have been tracing my car's overnight start up problem for months I'm getting used to it. The problem is like when you leave the car sitting for a long period like overnight, it will have a hard time starting in the morning. When you crank it will sort of start but immediately stumbles, rpm drop, and dies. It will take 3 tries before it will start. But if I step on the gas a bit to make the engine catch up, the engine will start no problem even on mornings. The car rans perfect, and it will start one click just after one successful start even if it is still a bit cold.
Checked the fueling, spark, MAF, start signal. Parts like AAC, coil pack, coil pack harness, FPR, igniter all fairly new. So the other day I was fooling around w/ the consult with both the GT-R and B13 w/ SR20VET. That's when I noticed the starting behavior of the GT-R's AAC valve.
When you crank the engine, % of the AAC valve will jump to 80% but when the engine is about to start it will rapidly drop to 10% (I'll feel the engine stumble & idle drop along with it) then % will slowly rise up to around 40%. Comparing it with the SR20, the behavior is totally different. On start ups it will rise to around 80% then SLOWLY drops % (won't dive like the GT-R), thus you can feel the engine drops idle along with it smoothly. That made me think maybe this is the problem I have been tracing all along.
So calling out GT-R gurus out there, help! Any inputs would be very much appreciated.