mk2

There's an ignition switch how-to that is excellent...! A fair bit of time needed though by the looks of things.

If it doesn't even try and start then cuts out, then not the imobiliser. Total shut down while driving sounds like it might be the crank sensor or main engine loom power bus (possibly caused by a relay or ignition switch). It should at least try and start for a moment if it's the immobiliser. Diagnostics are always available no matter which key you use. So if no OBD, most likely an electrical power supply issue. Are you getting ignition when cranking (try with all plugs out)? If no, then most likely above idea. If yes, then it's a fuelling problem.

To be sure where the problem comes from, more info is needed I guess... Not sure what else to suggest, as that code can be caused by quite a few things. Or a combination. But I'm fairly certain it has something to do with fuelling or air flow if that helps!

What do the measuring blocks look like in vcds? Fuelling, O2 numbers, temps and egr rates? My guess is probably iffy EGR valve?

Is the gti rack different to other models? Is it just the 'O' ring that needs to be replaced (you'd need to completely dimantle the rack of course)?

Yeah what got me is that the guys in vdub completely missed it. I mean come on, how can you miss a really loud tapping and think that it's a clogged/stuck/broken EGR valve. The guy who runs that car is not happy about it especially after I told him that there was probably nought wrong with the old EGR valve. Get rid and chip it... 👍🏻 More power. Blow the thing up properly. An AMF may as well have an exciting end of life rather than just wither and die with a duff cam or chain. The old injector loom is probably fine. Just crack all the brown plug covers off, squeeze the little spade terminal plugs a bit, so they're a tighter fit and whack 'em back in one by one. Will last forever. I did that to a Polo a while back and haven't heard a squeak since. Stupid bad design that loom wiring. 3mm spades are designed to take up to about 3-4A. The injector coils can sink over 20A... Mmmm.

Perfect.

I still wonder why the balance shaft and that wierd chain setup is there. The 3 cyl engines run just as rough without the balance shaft apparently (german lupo forum experiments). I discovered that you can tweak the idle slightly by messing with the injector lash adjusters. The rule is screw in to screw locking at max injection depth then back off 1/2 a turn. If vcds says an injector is chucking too much fuel in, i've found that backing off a bit more, like 3/4 turn does reduce the injection quantity very slightly. 👍🏻 On that concave and holed tappet, the oil must have been flooding out. I reckon not long until total catastrophic failure and game over there. Every car should have a magnetic sump plug like @CLAYTONJONES uses. Would certainly have been an early indicator that something was wrong.

Go for GL4-5 to help save the bronze bits. 5 is a bit corrosive. Yeah, fill up to filler hole or through speedo sensor hole. Drain at lowest point on diff crown gear. Use a 17mm spanner and spare wheel nut if you don't have the tool. I drain straight after having stopped to get all the bits floating around in the oil, before they have a chance to settle. I use the stuff you can get on ebay with no problems and change it every 20k miles. Much cheaper than halfords. 3.5L. https://www.ebay.co.uk/itm/121617362859

Sorry misread where the leak was... yeah, follow @ObjectiveAway's suggestion. In my head I thought it was leaking in a regular spot, from the seal behind the output flange. There's a hex cap bolt in the middle of the output flange. Yeah, just drain the box and whip off the tin cover. Quick easy job. Get a new seal or simply clean everything and chuck on some sealant

Here... https://forums.clublupo.co.uk/index.php?/topic/41812-the-definitive-gearbox-thread/page/12/&tab=comments#comment-1199802 I think you can just swap the seal once the flange has been pulled out. You need to remove the hex cap bolt first. Keep everything real clean

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.

From memory, it's a captive nut. But getting the holes to line up was the trouble I had. Try loosening off 37 and have another go. You may even have to jack up the engine or loosen off the engine mounts. Have fun... @Rich your thoughts?

Wallingford waitrose car park on the 5th at 11am (or around lunch time, 2-3h window) still works for me right now. Assuming weather holds out. Non members and anyone interested in buying/selling a Loop/Arosa is also very welcome of course. 👍🏻

What gear oil are you running in the box? Track use kills gear oil...