serious problem with gti !!

  1. L-plater Joined: Nov 2011 Preston Posts: 69 black mk2 vtr
    #1
    My gti has been running fine then started spluttering I changed the coil pack and plugs and it is the same I have took it to the garage and they don't have a clue what it is. When I changed the plugs 2 of the electrodes where good and the other 2 really black it happens anywhere past 2500 rpm and there is a black plug near the coil pack plug. It has 1 wire going to it and looks like it has broken from somewhere any help would be appreciated thanks josh
  2. Frequent Poster Joined: Apr 2012 Bradford/Leeds Posts: 775 03 R53 Mini Cooper S with a little extra going on
    #2
    O2 sensors, injectors, sounds like it over fuelling
  3. Frequent Poster Joined: Sep 2011 alfreton Posts: 533 saxoo vtr mk1, 104bhp
    #3
    would say a fuel issue, test the pump
  4. L-plater Joined: Nov 2011 Preston Posts: 69 black mk2 vtr
    #4
    Right I have got my hands on a diagnostic machine what I can use in live reading does anyone know readings of sensors ? Or where I can find them
  5. Regular Poster Joined: Sep 2011 Hertfordshire Posts: 250 2000 Saxo Woodland Green VTS, 2002 Mazda MX5
    #5
    i assume your talking about OBD-II port connection that reads what values your ECU are reading?

    MAP sensor = 0-5Volts typical values 0.4v to 4.8volts from Closed to WOT
    Inlet air temp sensor = NTC type resistance range from 50kOhms to 100Ohms from -30deg.C to 120deg.C
    Crank Sensor = need an oscilliscope to properly diagnosis this
    Knock sensor = again need an oscilliscope and give it a tap should see a spike signifying knock
    Coolant temp sensor = ranges from 11,000Ohms to 100Ohms from -30deg.C to 120deg.C
    Injectors = winding resistance at 20deg.C 14.5Ohms (providing there standard) fed by double function multi-relay
    O2 sensor (Upstream) = Rich = 0.6v - 0.9v, Lean = 0.1v - 0.3V (remember these function at above 350deg.C so don't take the values from cold start
    Stepper motor = need an oscilliscope to properly diagnose
    Throttle Potentiometer = 0.7v - 5v from closed to WOT also oscilliscope would diagnose its response throughout its opening range.