mk2

Pic in the how-to

It is possible. If you remove it and have a look at the sealing valve (the part that opens to allow exhaust gas into the inlet manifold), does it look like it fully closes? And is the mounting seal ok? The fault will probably only happen at idling, not when normal driving. So when you are in traffic, once warmed up, that is when the inlet air leak is detected. The fault is basically too much air is in the mixture, meaning that the engine is running too lean. The ECU knows this because it can see the gas result on the O2 sensor. It tries to fix the problem by closing the throttle at idle and increasing fuel. But when it reaches the limit, it can't add any more fuel or close the throttle any further, so it gives up and turns the light on. It can also be caused by low fuel pressure, blocked fuel filter, bad injector(s) or coolant temp sensor. The most common reason is that is an air leak in the inlet manifold. There is an old trick to find a leak, but it's a bit dangerous... get a small low pressure propane or butane pipe and while the engine is idling, blow propane around various parts of the engine. When the revs pick up a bit, propane is being sucked in to make the fuel mix stronger, and so the revs get a but faster. But sometimes the ECU notices the RPM goes up, so closes the throttle valve a bit to keep the RPM constant. You need to watch the O2 sensor reading while experimenting @Rich @Skezza @Silver! @Blue Loop what do you think?

Yeah, let us all know how you get on...

You can block off the EGR feed, which might clear that fault code. But the ECU will know and give you a different code! Worth an experiment If you get two codes, then you know it is not the EGR...

Sounds like an air leak. Check the brake vacuum pipe, as they often let air in. Late edit- just re-read your post. It also could be the fuel pressure regulator? I also remember reading something about the sump gas pipe/pcr thing... And welcome to club lupo! pics of car?

Could be gunge in the valve body galleries (inside the box). Did you use the right fluid? They're a bit fussy... What condition was the sump magnet in? Clean, furry? Also might be worth changing the box fluid filter. Once the box has become proper hot after a decent drive, it might clear? What condition was the old fluid (dirty/black or still light coloured)? The variable shift point is mainly determined by the throttle position sensor/throttle pedal sensor (I can't remember which one your model uses). And temperature sensors (engine and gearbox). If you have VAGCOM and an old laptop, you can look at all the sensor data without having to dismantle or randomly swapping everything. Sounds like you have a nice car 👍🏻 Oh, and welcome to club lupo! pics of car?

I could foresee an opportunity to bring in parts to order, for virtually any car... I mean there are even mk2 golfs where all the plastics and rubber are beyond hope (sun damage). But all the metal parts are just lovely. No idea how the 'business' would work logistically though. The smart money would be to be a breakers yard in Spain/Portugal, with a web site, offering cheap (and probably slow) shipping to northern europe. My (over a year) long attempts to have a spanish owner part with their hardly used Golf Country is not progressing very well...

If I knew of a cheap way to bring pallets in from the likes of Spain or Portugal, I'd buy, say, ten of each front and rear subframes from various breakers. When on hol recently, I visited a breakers' where there were fifty year old motors, in near mint condition bodyworkwise. I specifically looked closely at the weakpoints and they really did look like they were only a few months old. Even the black paint was still clean and shiny. Just shows how salt eats away at our cars. Yeah, most people don't go breakers yards when on hols. 🤷🏻‍♀️👍🏻 Because they're not available new from anywhere, and there are quite a few of us who are trying to keep our Lupos going forever, I'd definitely think that there's an option to make a few quid (not a lot though). Plus keep people happy. They go for around £75 each. So add shipping, plus something for my time (to remove/strip them), how much would people pay?

Rear subframe and coils probably need doing too? They look rough! I had both front and rear subframes (bought from someone on here) sandblasted. Presently sitting in dry storage waiting to be galvanised... My silver SDI has both F&R desperate to be changed.

Sounds like it's working again?

Test if your original motor works, without the window...

Damn that looks nice! Gorgeous. (My fav colour too).

Nice looking Lupo! 👍🏻😎 Try and clean your old motor before swapping for a different type. I don't think it will fit, but you can try. Which car does the replacement come from?

Common problem... there's a "how-to". Ideally, you need the exact same motor because the splined shaft needs to be the same. Other models are bigger. Oh, and welcome to club lupo 👍🏻 Pics of car?

The fuel filter non-return valve T insert has two 'O' rings, to stop any air getting sucked in. Might be worth checking if they're ok. Or maybe even replace them. @Skezza did a write up on how to do that from memory...

NOX is generated as a result of a high temperature burn using air, the nitrogen gas component actually getting hot enough to react with the oxygen in the air. =Nitrogen Oxides. The compression ratio of an engine affects the burn temperature, which is why in the US they dropped compression ratios down to something like 6:1 for petrol. CARB rules or something. Reduces smog. European petrols' is around 9:1. So naturally, diesel with it's high compression ratio (20:1) generates the most. The higher the compression ratio, the more efficient the burn. It's also why military explosives are so effective, they detonate generating huge pressures, and lots of expanding gas to propel metal stuff. But. Jet engines have a compression ratio of about 30:1. Go figure. And LHR is within ULEZ. I still think diesel is the best form of propulsion.

I dunno then... I do know that all SDI's have no leccy pump. They don't need one as the cam driven distribution (VE) pump has one built in, that can dry suck fuel through the filter to a height of about 10ft. Impressive actually. Working backwards on a TDi from memory, the PDI injector pumps up to injector pressure. The booster or cam driven pump pumps up to about 3bar to supply the injectors. Then there is a filter then the tank. If the booster pump can suck from the tank without a leccy feed, I have no idea. I suspect it can, once there's fuel in the system. But dry??? Maybe that's why "some" have a feed pump from/in the tank. 🤷🏻‍♀️

What on earth is that whirring sound then (for about 5 seconds), when the ignition is switched on? Sounds like a fuel pump, from the back of the car? Like, what?! And you can hear slushing sounds coming from under the car (fuel return cooler). Are there different versions of the TDi? I've only ever worked on one, to fix brakes.

Need lots more info

Yeah, what @Rich said...

Sounds like you've been entertained by the same youtube channels as me! Don't get me started... EVs vs Diesel. EVS catching fire, fifteen minute cities, ULEZ protests, emissions based parking charges etc etc. I live about 15 minutes drive from the nearest petrol station or supermarket, in the sticks, in the middle of nowhere. Cows in the field next door. If I didn't have a car, I don't think I could exist. No gas connection either. Only leccy, water and s l o w broadband... no 4/5G coverage either. There are millions of us in the same situation, so I genuinely don't know how the gov thinks we can live without a car. Really. Can't believe I'm talking politics on CL. Ray will probably delete my post

Euro 7, the new emissions standard, starts on the 1st of July 2025- only 18 months away. And as far as I understand it, the standard is the SAME for both diesel and petrol. And the cars have to have comprehensive emissions monitoring on board, to guarantee compliance for at least 10 (yes TEN) years! So a ten year old car in 2035 must emit the same as when it was new. I forsee many many 'faults' or recalls. As soon as thing start to get that strict, even the slightest variance will flag as a fault. It's almost a reason all on its own not to buy one. Unless it has something like a ten year guarantee. DPFs and EGR all clog up. How will they get around it?! It's going to get interesting

Add a drop of threadlock to it too. Might help. Bear in mind that the load is sideways on that bolt(pin), which is why I welded it on, like the original. It is a rubbish design though... I'd have used a simple C shaped thing, bolted directly to the door, with a rubber stop on the end. Old skool stylee. Bit like how saloon car boot hinges work.

Not as bad as Porsche or Mercedes...! 😂 As for economy, the old Polo and our Lupos are more economical. I think 20 years ago, economy was the thing. Now it's emissions. My SDIs consistently average about 65mpg. On a run, always over 80mpg. But I seriously wonder what small car VW will offer once all the Ups are gone? Any ideas or rumours? Anyone?

This might help