Hello - G37 Coupe with a stillen supercharger high boost pulley. It currently has a DW300 (G35 style) fuel pump. Runs great when warm started.. starts up on a dime when warm..... but when it's cold... it's like starting up a old car with a carburetor.

Tips or things I can look for? Car runs fantastic when started so bafffles why cold starts are so brutual.

 

check compression...

 

It's your tune i had similar issues

 

With foot off clutch... in "on" position... should fuel pump "prime" each time?

 

Are you experiencing long turnover? I am stillen sc myself.

 

Yes... when cold it will not start unless I pump the gas...just like an old carb'd 80's camero lol
sometimes can take 15-20 mins jus to start.

once started everything runs great. Warm starts are flawless.

Plugs? I have the gtr ones in since original install about 2 yrs ago. I've always had this issue tho sadly since installing stillen kit.

 

When it starts after turning over a lot I am guessing it kicks out blackish smoke? Cranking enrichment needs to be adjusted in the tune if so. Surfnazi is correct I imagine. The cranking enrichment is a table that varies with coolant temp I believe, which is why it works when it is warm, but not cold. My car has the same issue except it doesn't take as long to start.

 

It's the tune because it's outside the temperature tolerance for cold starts
Either retune it or keep block warmer on car

 

Thanks everyone for all the suggestions! Finally found it.... Turned out to be a vacuum leak from the 3 way plastic connecter that was on the driver side facing the motor, up top. I didn't even notice it because it wasn't even disconnected... just about half way on. I pushed the hose all the way in and put a clamp on it...now it starts ice cold on a dime. It must be connected to the POV, because it seems to be a lot louder now. Running great again.

So strange... Ive been battling this one for almost a year! haha.