A/F ratio Is not rich?

[PsiloX]

I have 1990 240sx I put a rb20det in it about 2 years ago. It's been running great. But I put a A/F ratio gauge (narrowband) in it. It jumps around like normal but it never goes to rich. From what I hear it should be rich at full throttle. I have a Welbro high flow full pump so I have lots of fuel pressure. I measured it once it was about 6 psi beyond stock. The exhaust even smells rich. When I took it to the track I ran 15 seconds flat. Not what I was hopeing for. Could I have a bad O2 sensor? MAF?

PS timing is good, I checked.

[JonPowell]

I never, and I mean NEVER depend on the disco lights for an accurate A/F ratio monitor....you want something to depend ong, get a wideband....

[PsiloX]

I just did a ecu diagnostic. Every thing was all ok. When I did the o2 sensor test, the light stayed off which I means it's rich.

When I did the 1/4 mile I did have a split seal on the o-ring that is between the fuel pump cradle assembly and the tank. I got a new o-ring from a 1984 200sx just a couple of days ago. Since then, the car seems a little more responsive. Could that have been why I was slow in the 1/4 mile? I know the fuel system is a closed system but would it really affect me that much.

[JonPowell]

1/4 mile time could be off because of a host of different reasons, bad timing, bad AF ratio, bad compression, bad traction, bad shifting, bad clutch, bad diff.....dont base engine tuning on quarter times. If you are really concerned, get to a dyno with wideband and have it tuned there.

If you have the Walbro fuel pump you WILL need an adjustable fuel pressure regulator.

I suggest the Nismo type A.