Normal A/F ratio behavior?

[Minty762]

I've been noticing something happening with my a/f ratio and am wondering if its normal.

 

When driving normally in gear and then putting the car in neutral, the a/f goes high, to 16-17, then reads null for a few seconds, which is to be expected.

 

What I'm seeing (or maybe just now noticing), is as the wideband begins to start reading again at idle, the ratio does the opposite, reads at 16-17 for a second or two, then backs down to the 14s, instead of going strait to 14s. The revs also seem to hang around 900 or so as this happens.

 

So I'm wondering if this is within normal behavior.

 

A/f is being monitored with an AEM uego. Car has full exhaust, intake, front mount, custom road tune (but is not yet tuned for the intercooler).

[Minty762]

Bump - anyone have any input?

[solidxsnake]

Might be a temperature thing? If your RPMs are above idle, like 1.5k or more, before you put the car in neutral, I'd expect the AFR to peg full-lean (16-17 or 20 or whatever your gauge will read under no combustion), and then as the car enters idle mode, I'd expect the AFRs to settle at a stoichiometric value (around 14.7 or so).

 

If the car is running fine otherwise, I wouldn't worry about it. There's not really enough information to diagnose... anything, really.

[Minty762]

Might be a temperature thing? If your RPMs are above idle, like 1.5k or more, before you put the car in neutral, I'd expect the AFR to peg full-lean (16-17 or 20 or whatever your gauge will read under no combustion), and then as the car enters idle mode, I'd expect the AFRs to settle at a stoichiometric value (around 14.7 or so).

 

If the car is running fine otherwise, I wouldn't worry about it. There's not really enough information to diagnose... anything, really.

 

The ration basically does change as you describe, I had just never noticed it backing back down to settle at stoich before and had though it began there immediately when idle reading started. Probably fine then.