on May 17, 2009, 3:21 pm, in reply to "Re: vauxhall astra stalling lack of power"
I think at idle LTFT is around +-5% and anything above +-15% will start to cause a problem and log a fault code.
+ figures is add more fuel
- figures is less fuel required
Normally + add more fuel is caused by an air leak or a fuelling issue such as MAF but this uses a map sensor. I think low fuel pressure can cause issues as well but i would've thought this would be noticed whilst driving.
Is the 02 reading in response to an air leak and actually detecting a correct fuelling condition. If you squirt brake cleaner up the air intake does the 02 sensor react to a sudden rich mixture.
I do know that these Astra's suffer with the exhaust manifold cracking where the CAT is joined to it. This could cause the 02 sensor to see a lean mixture but the gas readings don't really agree with this idea.
