Lean above 5400 RPM
07-28-2011, 05:30 PM
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Lean above 5400 RPM Finished up dyno tuning the other day and noticed that around 5400-5500 RPM the actual AFR leans out by .2 -.3 vs the commanded , wondering if this is an acceptable deviation or a sign of other problems in the fuel system, maybe a pump going bad etc or if it could be inaccuracies in the wideband itself.
I threw a panel filter in my 09' malibu a while back and it immediately threw a bank 1 too lean code, I cleaned the MAF, nothing. Took it into the dealership under warranty and they tested the pump which ended up being the culprit. The pump pressure was far under what it should have been at the higher loads and the additional airflow from the k&n panel was enough to push it over the edge. I'm actually glad I bought the panel filter otherwise who knows when it would have manifested itself. Guessing this could be possible here except I'm not throwing any codes.
Thoughts?
I threw a panel filter in my 09' malibu a while back and it immediately threw a bank 1 too lean code, I cleaned the MAF, nothing. Took it into the dealership under warranty and they tested the pump which ended up being the culprit. The pump pressure was far under what it should have been at the higher loads and the additional airflow from the k&n panel was enough to push it over the edge. I'm actually glad I bought the panel filter otherwise who knows when it would have manifested itself. Guessing this could be possible here except I'm not throwing any codes.
Thoughts?
