I need help! Instaled a rear mount turbo about two weeks ago and can not seem to find out why i am running lean. 2000 chevy tahoe 5.7 (old body style) Nelson tune(second tune long story but both run the same). starts and idles but as soon as i go into boost power falls off fast. WB02 reads 14.7 or leaner at idle, it never gets any richer at any point in the throttle range and when boost kicks in it reads 15-16-or 17 depending on the boost. Fuel pressure is 55 at idle and goes up to 65 the higher the rpm? I have not driven much (1-2miles) because I like my exhaust valves. I havent pushed it to full boost 7pounds for more then a few second at a time. meth comes on at 5 pounds. not much differance when it kicks in. any advice would help.

 

Do you have logging softwware and are you sending Nelson the logs?
I wouldn't push it at all (stay out of boost) until you find resolution.

 

All I have is a scan tool, it throws no codes, the o2s read the same as the WB02. Is it the tune or is it that fuel system can not keep up? I would think that it would only fall off a higher rpm at WOT and my fuel pressure would drop. i dont think that nelson could be this far off to start TWICE it is as if the didn't even tuch the tune. I THINK IM MISSING SOMETHIG STUPID JUST DONT KNOW WHAT.

 

If your fuel pressure is not dropping fuel system should be good. Sounds almost like its not entering PE. If your methanol system is working and you don't see AFR drop then something is seriously out of wack.

 

Are you running the stock spyder injection with that turbo?
The injectors (poppet valves) in the L31 motors are only 19 LB injectors and will not support much at all,on top of that the spyder injection is not all that great at all.

 

When the meth kicks in i dont see a differance because at that amount of boost it is soo lean that it is off the WB... 18 or higher.... but it feels like it gets a little more power. Stock spider... but i am also at 5000ft. it should be able to at least handle 2 pounds withouut running lean?

OK i have herd that i could update to the new style multiport injection but i have no clue on what it would take. has anyone done this or know what it takes.

 

Well with the stock spyder injection that is your problem
I would personally upgrade to a ramjet or atleast to a marine intake setup,those stock injectors are not gonna handle that.Nothing in the tuning as Nelson can not help that the stock injectors can not handle it.
I would upgrade fast or you are more than likley gonna have problems