lean at zero boost & vacuum. Normal?

[rexify]

I have a redtop sr with stock 370cc injectors. 225 lph walbro, sr maf, fmic, full 3" exhaust, and sr ECU. My AEM uego wide band says I am running 11.5-12 WOT and 14-15 Idle but I am running lean at 16.5 to 17 when my boost/vacuum gauge goes to 0 psi or around 0 psi. I was wondering if anyone runs lean at or around zero boost and zero vacuum and if this is normal on the sr20det? I just don't want to harm my sr. I have only put 1500 miles on it.

[Emperor_Tha]

yeah my car does that too. I don't know if it's normal. I plan to replace my o2 sensor and elbow soon when I get the money.

[rexify]

I think it might be my fuel pump going bad. Anyone else have this issue?

[boro drift]

It depends on the engines load. Light load=lean afr, heavy load=rich afr. Sounds like it's running right to me. If you you were getting 16-17:1 under heavy or partially heavy throttle then I would worry.

[Emperor_Tha]

it's mainly when shifting when it does that. When going into first then shifting at 2k-2.5k to second and once u hit the throttle about 5%to 30%. It goes very lean 16+, goes from 5 inhg and slowly creaps up to 0 psi. the car feels very slow,no bogging but its still moving then after 2sec or so afr drops down and then the car feels normal again. It happens in all the gear while after shifting.

It rarely happens but when it does it's Mainly in the first minute of driving. it will happen in Cold start, fully warm operating temp. Drive for a bit, get a quick bite, then drive.

[boro drift]

Generally, engine management systems won't go into open loop until 60-70% throttle. When you let off the throttle to shift or decelerate, the fueling is supposed to go lean. 15.5:1 is lean cruise, and 16.5:1 is lean best economy.