When shifting and looking at my A/F guage, I notice that it goes LEAN, and back up to RICH when I accellerate. In Neutral everything is fine, but when crusing in any gear, back to LEAN again.

Can anybody please tell me whats wrong?

 

thats normal.
i go up to 21 AFR at decel.
the injectors turn off on decel as far as i know.. causing a lean condition

 

Actually unless you're a nana driver the injectors don't normally turn off during shifting because the throttle doesn't get completely closed, but decelaration mixtures are always quite lean, because you don't need much (or any) power.

 

http://www.wbo2.com/

If you drive around with one of the units in the above URL, you'll notice if your driving along at a steady speed and just barely let off the throttle, the afr will go rich about one full afr number. Like if it read 14.5 and you just let off a nat's ***, the afr would go to approx 13.4. Must be sort of an accelerator pump type reason for that.

That really does not match your description, but I thought I'd throw it in since I still had the url in the *paste* mode.

 

That's interesting, NZ...During normal driving on my part (not being a nana, but not drag racing and trying to shift as fast as possible either), my TPS input goes to 1v (which means the throttle completely closes), and my O2 sensor's voltage goes to (or damn near) zero (no fuel)...As a side note, I always lift my foot entirely off of the throttle when shifting, which may not be what other guys do (such as you?)....

 

That's what I meant by nana driving... Yeah I guess if you're just cruising around the 'burbs a completely closed throttle on shifts is common, but during any form of enthusiastic driving I tend you just feather the throttle during shifts rather than close it completely. You'll still get a lean condition from doing this, which you'll see clearly on any mixture meter.

 

Decel fuel-cut
The stock ECU is programmed to cut all fuel when the TPS shows "closed" above ~1,800RPM.
So, if you lift off the throttle in between shifts, the stock ECU will shut off the fuel injectors.


-Ted

 

Cool, then Iam safe then rite? Never noticed before, oh well. Thanks

 

Yes, lean conditions are only dangerous when the engine is heavily loaded (i.e. WOT).
What you see is perfectly normal.


-Ted

 

The other variable is the throttle dash pot.
If it's set low or is not working the ECU will see closed instantly when shifting.
If it is set to spec or a little high, it will hold the throttle up for a second before closing, so you could get some fuel on shifts.