tomk555 Posted July 1, 2016 Report Share Posted July 1, 2016 (edited) hi all, have a bit of a missfire on the old arosa. have changed plugs, leads, coil and rotor arm and dizzy cap, however the miss has lessened but still there.. its not bad enough to log a fault on VCDS. i connected it up to my works exhaust probe to see what it is doing and the CO on idle is jumping between 0.3 ish and up to 0.7 ish. which is way above mot standard, has roughly 80 ppm on hydrocarbons and the lambda reading is down at 0.980 roughly which is to be expected from how it is running, ive cleaned the throttle body, reset it properly, cleaned the injectors given it a full service, short of changing the map sensor and coolant temp sensors i have changed pretty much everything, so i whipped off the cam cover, and found this. it looks like the camshaft lobes are slightly worn on the two on one side but a good few of the others look pretty good much better than these. these are the worst offenders, now is it worth changing the camshaft and the buckets. or does it look not too bad... bloody car only just bought it. cheers all Edited July 1, 2016 by tomk555 Photos upload Quote Link to comment Share on other sites More sharing options...
tomk555 Posted July 1, 2016 Author Report Share Posted July 1, 2016 Also just to add. The very tip of the lobe is quite sharp. And a little rounded off. Have checked the spark plugs and they are all black sooty but not wet which is indicating to me that possibly the exhaust valves are not opening quite long enough to get all the fumes out.. the misfire seems to be on the first two cylinders on the side closest to the cambelt. When it's running you can literally disconnect the number two injector and barely hear a difference in how it runs. Whereas any other cylinder injector when they are disconnected the noticeable difference to how the engine runs is very obvious. Thanks for any advice would be ideal don't want to go replacing stuff willy nilly lol. Quote Link to comment Share on other sites More sharing options...
Sausage Posted July 2, 2016 Report Share Posted July 2, 2016 Compression test. You needs one. Anytime there is a misfire, do a compression test as it means you start down the right path straight away without chucking money at it. Black and sooty plugs says too rich, so your ecu may be running the rich map because of wrong sensor info or you could have an induction leak. VCDS lite registered version will do live data on various things to help you out a bit too. Quote Link to comment Share on other sites More sharing options...
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