F8L Z71

WHat charts should I use to adjust the air fuel ratio?

I need to lean my motor out after installing my new cam because it is running so rich but I am not sure which tables to use. Once I find the table could I just use a multiply value say 2% or 4% etc???

ChrisB

Part throttle is controlled by o2's - you have no control over the A/F ratio directly - only the l-trim value (unless you run open loop).

Full throttle is tuned with the PE vs RPM table.

Chris

Tim98Z28

Ok if A/F ratio is controlled by the O2’s then how do I fix a part throttle pinging problem? I was thinking that I need to adjust the MAF tables to richen it up at part throttle. Is this correct?

Ragtop 99

iTrader: (7)

Tim:

If your LTRIMs are consistently high (e.g. +20, +25) you can use the MAF table. Increasing the value across the board by 10% (use the multiply by 110) would be a start.

Just make sure your problem is not due to an air leak letting in unmetered air or bad O2 sensors.

ChrisB

If your l-trims are out of whack I would adjust the MAF transfer function to get them around -4 or so.

A pinging problem should be addressed through the timing tables.

Chris

F8L Z71

Ok got it.

I would like to mention that if you try adding timing INSTEAD of leaning it out hen you are running rich, all it will do is mak eyou more rich as the PCM starts adding more fuel to compensate.

I lowered my timing back to stock which is 28deg on the top end and Iwill lean it out. Then I'll play with timing again.