98 Saxo VTR - Misfire Querie

  1. Newbie Joined: Aug 2006 Newcastle Upon Tyne Posts: 1 Vauxhall Corsa GSi 2.0 16v Redtop
    #1
    Just bought a 98 Saxo VTR.

    Engine misfires on idle and in low revs. It pulls hard in high revs and still feels quick but spluttery and rough in lower revs.

    Idles fine, sits around 900rpm and doesn't tinker up and down. This is because i've cleaned the ICV though.

    If i unplug the MAP sensor it cuts out.

    I've cleaned the CTS with some wet n dry sand paper as it was black.

    The spark plugs had a large gap (around 3mm either side) but on removing them i found that they're NGK - BKR6EK (as found in x14/x16 corsa 16v) plugs but they should be BKR6EZ. I had a new set of 6EKs so tried them and it's no different.

    I did find an air leak on inlet manifold so removed that, cleaned surfaces and put back with a little smear of sealer and the leaks gone.

    I've also cleaned the breather pipes out.


    I'm going to try a coil and leads tomorrow. Do you think those plugs would cause the misfire? Is it really that much difference between K and Z?

    Also, could the exhaust system cause the misfire? (i dont see how as it's standard and cant be lack of back pressure? unless cat is blocked?) Every flange on the system (standard with stainless backbox) has been caked in exhaust paste! But it doesn't appear to be leaking from anywhere?


    Any ideas appreciated.
  2. Established Member Joined: Apr 2009 Redcar Posts: 1971 2000 Posi Blue vtr
    #2
    http://www.sparkplugs.co.uk/pages/da...?partno=BKR6EZ
    http://www.sparkplugs.co.uk/pages/da...?partno=BKR6Ek

    Looks like the K has 2 electrodes but the dimensions and heat range are the same.

    I suspect your plug leads may be cracked and jumoing to earththrough the chambers the plugs sit in rather than across the electrodes as designed to do. Check leads, especially the rubber part that sits over the plug. If cracked you will likely get mis fires, especially in wet weather.
    Make sure coilpack is clean as well, migt be tracking accross any dirt/oil mixture present. make sure plug gaps are right as per manual (forgot specs but 1.2mm sounds familiar).
    Could be worth cleaning the TDC sensor while you have the toolbox out as well for peace of mind.
  3. L-plater Joined: May 2011 Posts: 57
    #3
    misfire


    1) Ignition Timing wrong at idle - check with a timing light
    2) Fuel dose wrong at idle - you name it - leave idling for 5 mins and look a the plugs. Sooty or glazed and super clean are the extremes
    3) Cam belt out by a tooth

    4)ECU

    5)wrong temp sensor

    6)Hairline crack in cat or manofold gasket or downpipe - gets oxygen to lambda sensor gives these issues