Does anyone know what the air fuel correction percentage should be on a UK 94 Turbo. NO cats, Blitz induction, 15 Psi boost Etc.
Been told it is currently running @ 18% & should be +/- 5%. Don't want to replace it if this is normal.

Cheers

Dean

 

Many induction kits make the MAF sensor under-read and so the closed loop control requires continuous positive air fuel correction to achieve the correct 14.7:1 air fuel ratio.

The worry is if your induction kit is making the full load timing too advanced and the mixture too lean.

Of course your MAF sensor could be rogered as well.

 

The afr correction is only active under zero boost (or vac) and is controlled by the ecu using the oxy sensor. Normal limits are plus/minus 25% but thats for range and 18% is not normal. Given that your fueling is correct on boost ... the problem is a "classic" and is the oxy sensor is failing. This is pretty typical occurance on your MY of car. With a good oxy sensor I would expect to seee plus/minus say 8% depending on conditions but not all at once ie say a 6% range moving within the 16% band.

cheers

 

Thanx for the Info Chaps, Makes me feel better about buying a new Oxy sensor now.
Cheers

Dean

 

Then guys more than 10% is ubnormal for a MY00, as I have seen values higher in my car time by time?
JIM

[Edited by JIM THEO - 11/25/2002 1:23:01 PM]