02WS6FREEBIRD

iTrader: (4)

Hey

I have been working on my tune with the AEM on the right side LT (no exhaust leaks) as the left side there was some leaking going on, got the tune as close as possible with the AEM (one run would be pos. and the next neg. and ended up splitting the difference) I have highflow cats mounted right up to the collectors and the left side went bad and when replaced the exhaust tech said the tune is lean because the cat material was real white and breaking apart because of the lean tune (could this be because the collector was leaking? (QTP headers) got the collector to where there is little or no leaking by using the 2400* patch material, anyway now did a new scan with the NB's (CL, STFT's only) and they said the car was real rich, giving me readings of neg. 10-20 on 4 separate scans....can this be?, I have read some don't think much of the AEM, are they off that much?, I really don't have a third to check other than a local shop with a dyno that uses a sniffer WB.

If I run CL would I not have to use what the NB's want or like now they will be pulling fuel all the time?, I would like to stay CL so I don't have to monitor the tune...if possible.

Thanks for any ideas

jimmyblue

iTrader: (11)

WB and NB are subject to the same spoofing by
exhaust air. Though different locations might see
it to different proportion, depending on leak location.

If you tuned against leak-bent original readings
then you may have pushed it rich and now it's not
needing that (by the instruments; the challenge is
always in knowing when the instruments lie).

Patrick G

iTrader: (14)

To get the most accurate reading at all loads and rpm with the NB sensors, it's best that you make all your O2 switchpoints 450 mv. Once you've done that, a fresh NB O2 sensor will be more accurate for chasing that perfect 14.63:1 A/F ratio than an inexpensive WB O2 sensor.