KYL98

I have recently rebuilt a 350 4bolt to put in my 91 Z. Its a 355 with corvette L98 heads, and has a ZZ4 cam in it with 1.6rr. My question is....do I need bigger injectors for this cam? It idles and drives fine..so I dont think I need a different PROM, but it just seems like it leans out on the higher side of the RPM. I know that TPI's die out about 4500, but this motor just seems like it wants more fuel? Would a adj fuel reg. fix this? The 02 sensor confirms the leaning, but its kinda old and needs to be replaced.....any help would really be great. Thanks...

D Stroy H8

Replace the O2 sensor. Aside from that, have you done a general tune up recently in regards to your ignition and fuel injection system, fuel pump and otherwise?

It could be one of these simple/cheap things before you decide you might need to bump fuel pressure &/or edit the prom.

KYL98

Yes I just did a tune up about a week ago....I used Ac Delco plugs(.045)...Taylor wires, MSD distributor, coil, cap and rotor(timing set at 28* adv at 3000rpm). The car also has a new Holley fuel pump and a K&N fuel filter. The injectors came from a 90 Vette TPI, but they are 22lb right? Im almost certain thats what mine originally had. Ill change the 02 sensor in the morning....dont know why I didnt change it to begin with.....

GTA91

iTrader: (1)

22# inj's should be plenty for that cam. You sure they are clean and flowing correctly???

bigals87z28

with a modded motor, you cant really go wrong with an afpr, there a good tool for tunning.

KYL98

well...I changed the 02 sensor today....and also got a new afpr...from TPIS....I set it to 50psi like they said...and drove it down the Interstate...it runs great now. I havent had a chance to check the 02 sensors reading, but it seems right now....and smells right if that makes sense. Also, just wondering how much my 170deg t-stat affects the mixture??? It definitely seems better though......