effects of running lean?

[cacasplat3]

sorry but i did a search and i'm not getting my question answered.....
anyways like the topic says, what are the effects on your engine(both diesel and gas) as a result of running a lean mixture? and why could this problem arise in the first place(other than a faulty o2 sensor)
thanks for the help

[Anil_Sooknanan]

to know if it's really a bad O2 sensor check the output voltage when you rev the engine if no change then it's a bad O2 if not (only at idle then check for a vacuum leak )

[cacasplat3]

^^^^but what are the effects on your engine of running lean?
this is what i would like to know.

[3stagevtec]

the Honda D15B engine uses a 'lean burn' mode of operation to help improve fuel economy..

The 3-stage VTEC engine runs in 12-valve mode up to around 3000rpm. In this range, running in ideal conditions will activate the 'lean-burn' mode, where air-fuel ratios as high as 20:1 can be used to take advantage of the intake swirl induced by the 12-valve operation. This lean-burn mode is what makes the 30km/l mileage (for constant 60kmh speed) possible. A green 'ECONO' LED lights up on the dash when lean-burn mode is engaged.

[Doom]

what are the effects on your engine of running lean?

more combustion chamber heat leading to melted plugs, melted pistons, cracked heads, overheating engine, blown head gasket
get the picture

[Dragsta]

well if u using it for speed, it better to run Rich than Lean....

otherwise, for Eco well, it go be better off lean...but not to much

[5fwd]

wht is a good af ratio to tune to...
11,12,13??

[stephanweaver]

14.7:1 or stoich

lean gives u more power, and is also more dangerous

[Dragsta]

lean gives u more power

i heard ppl talk abt that already.

[3line]

I prefer losse some hp by running rich than having to rebuild my engine..

[saltydog]

Well there is a fine line that every engine like to run at for peak performance. Basically it is a juggling act that we like to call tuning. 14.7 is perfect for idle but if you tune to this under load you will be looking for an engine soon. Most engines like about 12.5 A/R ratio. Rich conditions actually lose power and cause engine damage with prolonged running rich. If you have no means of mapping your ecu for fuel and timing and no knowlege of how the combustion process takes place then I suggest you leave it to persons that do.

[cacasplat3]

Doom, thanks for the info....much appreciated.