Leaderboard

Just helped out someone over the WE with their rough running tdi, having come to me after spending over £500 with vdubs, who didn't diagnose it right! I said I'd be happy to stand up in court to tell them them what i thought of their 'professional' skill level. Huh! They changed the EGR valve. Wrong! I reckon @Rich, @Blue Loop, @Skajme or @RAB would be able to diagnose it in under 5 seconds. Took me about 30... Symptoms were obviously misfiring, running on only two cyls. until warmed up. Started ok, and had a loud tapping noise- really loud with the air inlet duct removed. VCDS showed a big injection quantity imbalance between cylinders at idle- trying to add fuel to cyl 1 and pull from 2 & 3. Obviously air starved on no.1 with the inlet valve not fully opening. It's amazing how vdub ECUs actually measure the rotation time between injection pulses and trim the injection timing to achieve a smooth idle. When a power stroke has more push than the other cyls, it obviously takes less time to rotate. So it adds fuel to the weaker cylinder and pulls from the others to try and even out the power strokes. Neat idea. This 2001 Lupo had 165k miles on it, with a decent history... Down to the breakers yard to grab a camshaft (and a tappet) from a 9N Polo, which was pretty much like new still. It always seems to be the lobe next to the pulley that goes, having seen a few worn cams at the breakers. The engine is at a slight angle, with the gearbox end being slightly lower. Straight forward job- just loosen the timing belt and tensioner. Pop off the valve cover and bearing caps. Pull the dodgy tappet. Pop off the pulley, swap over everything and back together again. You don't even need to remove the high pressure fuel pump or adjust the injection timing as everything is precision made.

This manual specifically mentions they are Lupo compatible.

Why don't you turn your headlights on?