ls1builder

just done a heads cam intake and header install on a 97 c5 ok heres what i got its giving the 0171 and 0174 lean codes i'm running it open header for now just to make sure every thing is ok before i button it all up is there any way that the o2 are picking up fresh air and causeing it to say its running lean??? i hoked up a vacuum pump to it and it held vacuum great so that would clear that theory of a vacuum leak i think the cam is a ms4 with a 111.5 lsa and tsp ls6 stage one heads and ls6 intake and tsp long tube headers. thanks for any help yall can give me.

brad8266

iTrader: (23)

Yeah the open headers can cause the O2's to sense leanness from the fresh air that close to the sensor, and to add on top of that the cam you are using has enough overlap in it to pull fresh air through the combustion chambers too.

Get your exhaust on, clear the codes and go from there. You should be fine since it hold vacuum.

ls1builder

thanks alot i kinda figured that much lsa would pull a little back didnt know if it would pick it up on the 02 though thanks for the reply if it works i'll let ya know if it dont i'll let ya know but i think it will clear it up also