Hi guys, I have a 2003 Fabia 1.4 MPI 8v with just shy of 100k on the clock. When I bought it last week the tappets were rattling like crazy so the mechanic over the road helped me to readjust them. I've since moved to a different town and have basically no tools (yay). The engine management light has come on and the engine runs so rough to the point of stalling when it drops back to idle when cold. I bought a fault code reader off ebay (U281) and it's telling me the problem is a cylinder 3 and 4 misfire.

 

I'm used to working on motorbikes but not so much on cars. Does anyone know where I should start to figure out what's causing it? Not sure if it's still something to do with the valve clearances or if it's a new fault.

I thought they were hydraulic on the 1.4 MPi and so don't need adjusting?

 

You can adjust them but maybe they have been done wrong. Perhaps too tight.

 

Phil

They are hydraulic but there's adjusters on the rocker arms and 6 of them were making a hell of a racket. We adjusted them to the point there was no play in them, but I can't see how that would only be causing a misfire in cylinders 3 and 4. Surely if we'd adjusted them wrong the whole thing would be firing badly?

Sounds to me like the valves are now not closing fully causing a misfire, there should always be some lash in a valvetrain, hydraulics will close up a clearance but not slack it off if it's too tight in the first place.

maybe it's valve jacking   I think you need vag com check and then a compression /leak test when hot

I already posted a comprehensive reply in your original thread. http://www.briskoda.net/forums/topic/360977-new-car-new-problems/