I have a B20z block fully built,wit a type r head semi built.The car idles fine runs fine till the vtec hits then it goes lean really bad.It started when I tried to tune it once I broke it in wit 310 rc injector on. Crome.So then I got 650cc injectors,255 walbro,fuel filter new and still does it.The voltage on the gas pump doesn't change but my fuel drops...I even tried tunning it on a neptune and still does the same thing...if any one has any clue plz help....thx

 

How do you know it's a lean problem? Have you replaced the fuel filter, tested the FPR, and measured the fuel pressure?

 

Pardon me for saying but if you're leaning out on 650 injectors but it sounds like you need to take it to a professional to get a real tune.

 

Agreed with a professional tune. you shouldnt have any need for injectors quite that large on an NA setup.

Post up a screenshot of your high and low cam fuel and ignition on crome.