AMF Soot: LMM Cause? (Logs Included)

Hello everyone,

My 1.4 TDI AMF, manufactured in 2000, has recently been consuming about a liter more fuel and producing more smoke than usual. The performance is still okay.

I was wondering if it could be the LMM (likely mass meter) that is possibly displaying values that are too high > Russian. However, it doesn't seem to be the case.
According to the target value table, the actual mass flow rate (LMM) should be above 700 when operating at full load. However, I can only achieve 700 with great difficulty.

119,000 kilometers driven, 80,000 kilometers with chip. Unfortunately, I don't have logs from when the original software was installed.

The attached file contains 2 acceleration tests performed in 4th gear with the following engine speeds: 3, 8, and 11 RPM.

I have an old log from 2004 with readings of 2, 8, and 11. It doesn't look much different. Unfortunately, the mass airflow sensor (MAF) values are not included in the log.
The smoke limit is always the lowest value.

LuFi is new, and all the wheels are spinning freely.

Who has an idea?
If this helps, I might be able to log the charge air temperature (CAT) sensor data again sometime. Maybe the intercooler is clogged, and it's only producing soot because not enough or too hot air is getting through... and my chip is just giving me a flat spot anyway.

Regards,

Olaf.

P.S.
AGR is disconnected.

Hi Olaf,

I took a look at your log and an AMF serial file.
You can throw your tuning software in the toilet; you can safely say that it either made you look foolish or you got exactly what you paid for.

"The turbocharger boost pressure is standard (=far too little air for the specified power output within the torque limit), and the engine is running completely within the soot reduction mode."
Either the engine has always run poorly with this fuel, or certain changes made to it are so poorly executed that, despite an excessively small amount of air being drawn in (due to a problem with the engine hardware/peripherals), too much fuel is being injected.
Sure, you can send me the creator of the file via private message, but I think I already know who it is, because only one person seems to be responsible for all this nonsense.

There might be a problem with your EGR valve. It's not achieving the required EGR rate at idle, and the measured air mass is far too low when the engine is running at full throttle.

My tips for you:
1. Request a refund from the tuner and have the car restored to its original factory settings.
2.) Repair engine faults; I would start by checking the EGR valve and its hoses.
3.) Go to a tuner who knows what they're doing, someone who doesn't just randomly adjust the mixer settings and arbitrarily increase certain parameters by +20% here and there.
4.) If the air mass reading is not due to a faulty mass airflow sensor (MAF), using that file and continuing to experience the error will quickly damage your turbocharger.

Best regards, Rainer.

Quote:

AGR is disconnected.

Okay, I just saw that. Well, does the valve actually close properly? You should check that. Otherwise, your intake or exhaust system might be clogged, or the mass airflow sensor (MAF) might be faulty...

Best regards, Rainer.

Thank you for viewing.
@Rainer
It's no surprise to me that the file goes through the smoke detection system.
It's a shame that I didn't log any LMM values in the old logs from 2004 (only MWB 2.8.11 was logged).

The chip is coming from our main office. If you need the exact names of the people involved, please let me know. But it's usually the same people who handle these things.

Returns are a tricky thing, considering this chip was manufactured in 2003.
One could, of course, attempt to prove fraudulent intent. However, in such a case, one would have to demonstrate deliberate intent. Inability alone is not sufficient.
They're not going to pay me anything, anyway. And they've failed to fix the problem countless times.

My first AMF (Air Mass Flow sensor) was replaced in 2000 with 20,000 km on the clock. Shortly after, I started experiencing boost pressure overshoots and intermittent limp mode (boost pressure below the minimum threshold), which I could reproduce while driving uphill under partial load. They replaced the N75 valve, but it didn't fix the problem. Another customer's AMF had the same issue. Apparently, replacing the turbocharger didn't resolve the problem for them either.
The car had to be reworked twice because of excessive soot production below 2000 RPM. Since I was still not completely satisfied, I heard comments like, "If you want even less power, you can just remove the chip altogether."
In the end, a compromise was reached that I found acceptable. Although I got the impression that they spent hours working on the file, and in reality, nothing significant was ever changed. So, looking back, it's quite possible that they were just messing with me.

Anyway, the turbocharger was shot at 100,000 km. Oil was leaking through the shaft and into the intercooler. A new turbocharger eliminated the overboost condition.

For my second car (AMF), I went back to that shop because their prices, including the inspection report and warranty on the transmission for 100,000 km, were unbeatable (at least for me, as a "regular" customer).
"Also, other chips that I had installed through AMF always felt too weak in the lower RPM range... You'd really get a jolt in the neck above 2000 RPM. However, the pressure in the lower RPM range is very pleasant for city driving, and I'm willing to accept a little more smoke for that. Overall, you just drive more relaxed and also more fuel-efficient."
With XXX, I knew exactly what I was getting.
"I told them from the beginning that I wanted less smoke (and popping) from the exhaust, and no more surging at 1100 RPM under partial load. Unfortunately, neither of those things worked. After one attempt at fixing it, I gave up, but I left the chip installed because the car at least drove better than it did stock, and I would have had to wait another hour to get it removed (I don't live right around the corner)."

In 2004, I once "outsmarted" another well-known tuning company at the 24-hour race by secretly remapping their engine file in the pit lane. Unfortunately, their car experienced problems during Friday's practice session, leaving no time for me to do it (I also had to leave on Sunday).
I didn't worry about it any further, since the machine was still running. I put a new loader on standby as a backup and planned to address the issue again only when the next loader breaks down. However, that hasn't happened yet.

"Only now is the fuel consumption no longer quite right, and the soot has increased to a level that I'm not comfortable with (especially above 2000 RPM)."

Could it be that the LLK is full of oil?
Okay, before I go through all this trouble, I'll probably replace the mass airflow sensor (MAF) first. If I remove it, hopefully the oil will flow out towards me if the turbocharger is leaking badly.
On the other hand, a weak LLM (likely referring to a Low-Voltage Module) could be an indicator of a faulty charging coil. I noticed the charging defect in the other car because it went into emergency mode and the error memory showed complaints about an implausible mass airflow sensor (MAF) signal. Cleaning the MAF sensor and the intercooler helped after replacing the charging coil. It was also necessary because there was over a liter of oil in the entire intake system.

Regarding the AGR:
Why would it suddenly stop being airtight? It had been disconnected for ages and never reconnected (the hose was removed). I find that unlikely, at least.

Regarding the turbocharger:
Could it be that the boost pressure reading is being manipulated somehow to prevent VW from immediately detecting the chip? However, that would be pointless anyway, since the chip can be identified by the soot sensor.

It's kind of contradictory that the car is producing soot, which suggests too little boost pressure, against the theory that the mass airflow sensor (MAF) is showing low values. It's strange that the power is still there. I'm wondering if I should check the MAF sensor now, or wait until I have a spare one on hand (for a cheap price), just in case.


Regards,

Olaf.

Okay, I've taken the intake manifolds apart. There's hardly any oil. Also, nothing came out from the bottom of the oil cooler.
The EGR valve is leaking a little, but it's still working.
The LMM appears to be in excellent, like-new condition.
I'm not sure how to quickly check the exhaust system for leaks. The muffler is new, but the rest is original. I don't think anything is leaking, though.
So, let's switch the LLM for now.

However, if it's already running with a too-low LMM signal, I doubt that a new part will make it better.

Regards,

Olaf.

I have already replaced the mass airflow sensor.
The LMM values are now (surprisingly) within the acceptable range.
Regarding soot and fuel consumption, I can't say anything yet, as there is currently RME in the tank. I will report back when I have more information, but I doubt much will change.

Regards,

Olaf.

P.S.
I ran the RME completely out. The engine definitely runs better with diesel than it did before. However, I'm also aware that even small amounts of RME in the mixture can significantly change the visible soot behavior. Nevertheless, I believe it has gotten noticeably better. Currently, the temptation to use RME is quite strong, as the price difference is so large again here that it's worth sacrificing a little bit of low-end torque. I've never had problems with faulty injectors in the past. Perhaps that's because I'm not a staunch advocate and I certainly don't use RME constantly, nor do I leave the car standing for extended periods with RME in the fuel system.

Regarding fuel consumption, I can't provide any specific details yet, as my driving patterns have been somewhat different in recent weeks (with more long-distance driving).

Since RME prices have increased so much that it's almost not worth using it voluntarily, I've been running on pure diesel again for a while.

The new LMM (likely referring to a mass airflow meter) has definitely significantly reduced soot emissions. However, I don't have an explanation for this yet... A too-low LMM value shouldn't actually lead to more soot, should it?

P.S.
"The fuel consumption is a little better, but not as good as it used to be. However, my driving patterns have also changed. Before, I had longer stretches of slow city driving with relatively favorable traffic light sequences. Now, city trips are mostly short distances with a cold engine (6-8 km), and otherwise, I'm mostly driving on moderately fast highways. The ratio of highway to city driving is approximately 20/80."
The standard AB route is 40 km long, with 25% at a speed of 100 km/h (actual speed according to GPS), 50% at 140 km/h, and 25% at 170 km/h.
In the end, I'm getting a fuel consumption of just under 7 liters, or slightly below that. Previously, I was closer to the 5-liter range.
Well, I suppose I'll consider the matter resolved anyway.

The new LMM has definitely significantly reduced the soot. I only have one explanation for this so far... A too-low LMM value shouldn't actually lead to more soot?!

Hello,

Yes, especially if you're working on the smoke limitation system alone, and it was 'classically' modified during the chip tuning process, which, unfortunately, seems likely based on what was written above.

The Lambda values within the smoke boundary are not constant. The deeper you go into it, the more blurry it becomes, because otherwise, acceleration would be impossible without a very low Lambda value.

Best regards, Jochen.

But purely from a physical perspective, wouldn't a new mass airflow sensor actually limit the amount of air available? So why is it that I suddenly don't have the "smoke sprayer" anymore, but only the normal smoke at full throttle, which I've always had?

Regards,

Olaf.

Okay,

However, if you get stuck in the smoke zone, the injection amount is reduced, which slows down the formation of the LD (light diesel particulate matter) again.
Therefore, you have fewer language model resources available during the interaction, which negatively affects the user experience.

Best regards, Jochen.

Okay, I understand!

"You're consuming 7 liters? That can't be right! I drive pretty fast (with speeds around 200 km/h whenever possible, and lots of acceleration, plus city driving and very little country roads)."
"And I need about 6.5 liters [of fuel]. With a fully loaded car, it can sometimes be 7-7.5 liters, but I have a 1.9-liter engine and the car weighs about 1650 kg!"

If I want to, I can also bring the number down below 6 (in which case, I would only accelerate up to a maximum of 3500 RPM).


That's definitely not okay!

Don't panic...
"Then something wouldn't be right with every car I drive... The fuel consumption figures that some people claim, I only ever achieve when I drive much more conservatively than other people suggest."

This is already my second AMF Lupo, and my previous one also rarely achieved less than 5 liters per 100 km, even without a chip.
I've driven it for over 10,000 kilometers.
Normally, I try not to exceed 7 liters per 100 kilometers with my driving style... And I managed to do that again.
It's not that you can't achieve 5 liters per 100 kilometers. It's just that, in practice, I don't drive that efficiently. That's why I prefer to base my calculations on a driving profile that I frequently experience and that is reproducible in my actual driving conditions.
"200 km/h where possible" is quite relative. When it comes to fuel consumption, these figures are often exaggerated. If I write 170, I mean 185 on the speedometer. If the speed limit is 100, then the speedometer shows just under 110.

The increased weight of the 1.9-liter engine is hardly noticeable in everyday driving. However, the Lupo has a much higher aerodynamic drag. The difference compared to the 3.0-liter model is quite significant. Also, my car weighs 1055 kg even when empty.

With my current driving habits, around 6 liters per 100 kilometers is acceptable.
We still have a 535d (with a mandatory automatic transmission), and I use about 10 liters.
On the previous 530i gasoline model with the SMG transmission, the fuel consumption was 11.5 - almost 12 liters.
The Honda Jazz with a 1.4 CVT engine consumes approximately 7-8 liters (but without using the air conditioning, it quickly goes up to 11 liters).
Oh yeah, during a test drive in the new Mini Cooper automatic, I used 11.9 liters (approximately 2.5 gallons) on the highway (no excessive speed, not reaching top speed) over a distance of about 100 km (62 miles). But maybe the car hadn't been fully broken in yet. I found it surprising that the 530i consumed less fuel when driven at a faster pace.

I checked on Spritmonitor for the 1.4 TDI Lupo. People who own the same car and whose driving style I know, and who use the term "volle Lotte" (meaning they're driving it hard), also report consumption of around 6-8 liters at higher speeds.

Regarding the driving style:
The driving profile clearly prioritizes forward progress. Of course, the lowest possible gear is used, and there is no unnecessary acceleration towards red traffic lights or full acceleration.
However, for example, if a traffic light sequence is unknown and there's a chance to reach it at a reasonable speed while the light is still green, this will be attempted even if the engine is warm.
Whenever traffic conditions allow, and within legal limits, the maximum speed, including measurement tolerances and speedometer readings, will be reached or maintained by keeping pace with the flow of traffic. On the highway, I drive in a way that I usually don't need to use the brakes, but I remain attentive.

For cars with older engines in Latin America, things can get even worse. For example, the Ford Ecosport (which is essentially a Fusion with slightly larger tires) with the 1.6-liter, 92 horsepower engine typically averages around 15 liters of gasoline per 100 kilometers on highway driving (I've driven this car for 11,000 km). The aerodynamic drag coefficient (cw-value) of the pseudo-off-road variant is simply disastrous, and the engine is prone to fuel inefficiency anyway.
My father's fuel consumption figures are usually significantly higher for similar cars, so the driving style can't be that bad. Also, check Spritmonitor...
Sure, I can comfortably drive it with 5 liters per 100 kilometers when I'm not in a hurry and not driving in city traffic with a cold engine.

"On the standard highway route, I typically gain around 4-10 minutes compared to driving with a fuel consumption of around 5 liters per 100 km, depending on traffic conditions. I consider that a significant amount, especially considering the total driving time is rarely more than 25 minutes. However, I sometimes drive a bit faster than the speed limit when there's a line of cars ahead of me, and there are speed cameras or mobile radar units nearby."

I don't really drive cautiously; I average about 10 liters with the 2.5L TDI in my A6. (My brother gets 7 liters with the same car). I also average 13 liters with my father's 1.8T (same driving profile as my TDI), but sometimes it consumes as much as 18 liters (it's chipped). I'm quite happy with my fuel consumption .

"The 200 I'm seeing are 200 according to the GPS (the speedometer reads 215-220). The weight doesn't have a huge impact on the top speed, but it does affect fuel consumption. For example, even with a full car, I'm already exceeding the normal fuel consumption, and here we're talking about 50% more weight..."

I'd be okay with 5 liters for a Lupo, but 7 liters? At that point, it's not worth it to drive such a small car.

Based on your other consumption figures, I can tell that you're not the type of person who always drives aggressively (e.g., with a cold engine), but that's the only way I can explain how you're getting 7 liters per 100km with a 1.4-liter engine.

You're right, don't always drive at full throttle for no reason.
I haven't actually seen any significant differences in fuel consumption between the 1.4 and 1.9 TDI engines so far.
As I said... I needed a full 7 liters before the new mass airflow sensor. Now I'm using less, but I'm still in the 6-liter range. However, I don't really have a good comparison of what I would need with a different car, given my current driving profile. Unfortunately, it's almost 95% highway driving or stop-and-go city traffic under 10 km with a cold engine. Pretty much any car would consume a lot of fuel in those conditions.

I mainly got the small car because of its length. Due to parking situations, I absolutely need a car that's shorter than a Polo 6N or a B-Corsa. Anything bigger than that just becomes annoying, and it's better to ride a bike. However, it's really inconvenient for grocery shopping because when you're fully loaded on a bike, bags often break, etc. Plus, it's uncomfortable in this weather.
Unfortunately, the Lupo is one of the few cars in its size class where three people can comfortably sit. Aside from the Opel Agila and similar models, which are not even comparable in terms of performance, other options like the Aygo and its competitors simply don't have enough power.
The Fiat 500 also doesn't have a decent engine; the diesel engine is unfortunately too weak for that car... it would probably be okay in the Panda... and the back seats are unusable due to the lack of legroom and the flat rear.
Unfortunately, the space in the back of the Mini is also quite cramped if there are people around 1.80 meters tall sitting in the front.

Well, I have no idea what I can do about it. In any case, whenever I drive with anyone else (except with a Lupo 3L), I always have the lowest fuel consumption. So, the car can't be that broken.

Until the days.

The Fiat 500 also doesn't have a decent engine, and unfortunately, the diesel engine is too weak for my taste in that car.

The 1.3 CDTI is a great engine, as long as you can deal with the turbo lag.
And is it too weak?
It's simply a matter of the software. Even in the standard trim, you can get 90 horsepower.
It ran smoothly at Opel in Dudenhofen, producing up to 115 horsepower.

Furthermore, it will hardly make a difference whether it's a Panda or a 500. The latter is the first one with a shortened wheelbase and (almost) double the price .

Best regards, Jochen.