Back to Forum
Post a Response
    Vectra 2001/Z18XE/WOLOJBF6817053485 Archived Message

    Posted by dave stock on April 10, 2008, 1:21 pm


    Vehicle failed MOT on high emissions (CO off the scale at fast idle..seemingly). Customer changed O2 sensor and asked me to check emissions before he took it for re-test.
    Emissions now weak at both idle and fast idle.
    (Readings below at fast idle)
    CO-0.00
    HC- 1ppm
    CO2 - 12.36
    O2 - 4.41
    Lambda - 1.25


    Using AD I got Fault code P0170 O2 sensor signal low. Confirmed with scope...sensor not switching but stays steady at around 39mv. (engine hot)
    Will not even switch if I blip throttle.
    After cat O2 sensor steady at about 214mv

    Other readings EGR valve logged as Open
    EGR feedback - 0.00v
    EGR position feedback 0%.
    O2sensor loop open
    Bank1 sensor 1 - AF ratio = Lean
    Bank2 sensor 2 - AF ratio = Lean.
    Short Term Fuel trim = 0%

    I thought I would clean/blank off EGR but here is a problem..I can't find one..is it under the Inlet manifold ?.I couldn't look from under the vehicle cos it was standing on wet dolomite but i can't feel one. There is a little device on the side of manifold which i understand is called a Varitract ?.... something I've never noticed before.
    Exhaust is sound and customer says the car runs well. I can find no air leaks/split pipes.
    MAF sensor voltage on snap acceleration goes up to about 3.8v.

    any suggestions...

    regards
    Dave Stock

    Message Thread:


Copyright © uk autotalk