Ok so I just got my first z, I love it! It is in great shape, motor was rebuild with wisecos pistons and new bearings 10k ago. Sport 500 turbos and a supposedly aftermarket ecu. Now she is fast, but I fear it is not running like it should. When I stomp it the a/f ratio is a solid 12-13, which is fine I've heard. But when it's cruising around 2500 it runs lean according to my gauge, It goes from 14 all the way almost to 16, but stays mostly in the middle of those. Also when I let off to stop the gauge says it's all th way lean and show red dashes? Any ideas? Would unplugging the fpr's richen It up, what If I use higher octane fuel? I just dot want to Melt or crack a piston. Please help!

 

Welcome to ZDriver!

The a/f ratio will vary depending on the throttle position (where your foot is on the gas pedal). Obviously the car isn't going to run rich if your foot is off the throttle and the car is slowing down.

 

always run 91 octane or better where available and get a legit dyno tune instead of one of those pretuned ECU's.

 

Will it hurt my car if i don't and drive as is?

 

Uh, yeah. Turbo cars need premium fuel... I never run less than 93 octane. (If you're referring to the ECU part, no. I ran a JWT general program on my GT2530 Z32 for years without issue. You'll make more power with a custom tune, but your car will run fine with a general one.)

And what kind of A/F gauge is this? Narrowband or wideband?

 

It's an aem wideband, and yes 93 always! I was referring to the ecu tune, I just ordered a new tps so maybe that will help. Then I'll clean the iac and stuff as the idle is lopeing.