I just got a aem wideband and i noticed that when i left off the gas it goes 15+ to not registering when i let off above 3,000rpm. Is that normal? Idles around 13.5 and 12.1 WOT.

 

From what I've seen, that's normal - perhaps even desirable. As long as you don't go so lean as to misfire and make the transition back to idle (or cruise) smoothly you're fine.

I use a WB02 sensor also - and since MAP values are used to calculate injector open times.. you can pretty accurately manage AFR during deceleration.

What are you using for engine management?

Mark

 

Right now just a Chipped P28 with a basemap.

Alot of times when i left off the gas i get loud pops

 

Prob. too lean then - it won't hurt things, well, I suppose it could swell the muffler a bit if it got bad enough... ; ' )

If you can, it would be better to tune it a bit and try to keep the AFR in 15-17 range when you're in full-on deceleration.

You MAP is probably between -10 to -14 PSIg decelerating; I shoot for about 15.5:1 there and it seems to work pretty well.

Mark

 

Lean is how a.motor deaccells. You'll always flatline when you let off, if you don't, you're too rich. Your idle is a bit rich, wot is good.

FWIW, I idle 14.3-15.8, wot is 11.8-12.2. I know my car is rich.

 

Virtually all fuel injected cars go completely lean on decell. It actually cuts fuel completely. This is normal, safe, and desirable.

 

ok good, for a moment i thought my engine was getting damaged