AJM Leistungsverlust kein Ladedruck | Posts 16+

Hi,
As I said, you don't need to look for the cause of the performance loss in the charger.
What is the compression ratio? What are the valve timings?
hg
Herbert.

I had issues with the valve timing, and both tools were stuck. I recently checked them again.

Good day.

Please provide an online log with all air values and engine speed. It should be MWB 1 and 11.

Shift to 4th gear at 1800-2000 RPM, please log it and accelerate fully.

And please, please, please, no 3-minute log files.

Best, Tobi.

Leak testing is also helpful.

Does the AGR open and close as it should?

I would suspect a faulty mass airflow sensor (MAF) that is no longer reaching its maximum values and is sluggish. To confirm this, we need a log.

Okay, I'm ready. Please provide the German text you want me to translate.

Hi!

I also suspect the LMM (likely mass meter).

I'm not sure if I'm imagining this correctly.
"But that's what's known as a vicious cycle:"

You can conveniently check the LMM (lambda measurement module) values while driving with your laptop. That's how I always did it: laptop on the passenger seat, and off we go. The best way is to go uphill, slightly above the middle RPM range, and floor it.

You can usually tell if the value is too low.

If something is wrong with the turbocharger, the intercooler piping, or the control system, it will build up insufficient boost pressure, resulting in a loss of engine power and a reduced air intake.
Ultimately, the LMM value is also too low.

If the mass airflow sensor (MAF) reports a low airflow due to contamination or a defect, the engine receives insufficient fuel, the turbocharger receives less boost, and the MAF sensor reading is also low, further exacerbating the already low measurement.

So, it's a vicious cycle, but you have to start somewhere.
It's generally a good idea to start with a new or definitely functional LMM (Linear Magnetic Module) in this situation.
and if it's possible to temporarily install it for testing purposes.
That's the fastest and easiest way.

Okay, so my personal theory, and I'm sure I'll be corrected quickly if it's wrong.

...then the engine would be running at the smoke limit, or am I wrong?
hg
Herbert.

Herbert wrote:

... then the engine would be running at the smoke limit, or am I wrong? hg Herbert

If the mass airflow sensor (MAF) measures too little air, creating a "virtual" smoke limit, the engine control unit (ECU) interprets this as the engine receiving insufficient air, which is not actually the case in reality.

The engine control unit can be easily checked in measurement block 8; please refer to the linked technical article for troubleshooting performance issues.

Best regards, Rainer.

To be honest, I just can't manage it anymore...

However, he just won't let me go...

I checked the fuel pressure again because, in my opinion, it's injecting too little fuel.

In the initial stage, after turning on the ignition, I'm getting a reading of 0.5-0.6 bar.
So, I have one with a pre-lift pump.

I used two different watches during the exam.

The first one is shaking wildly. It probably has less internal damping and swings freely at idle, fluctuating between 3 and 6 bar. At approximately 3500 RPM, the needle swings between 6 and 10 bar.

At 2 o'clock, when I looked at the fuel gauge, I couldn't see anything; the needle seemed to be fluctuating wildly between 1 and 10.

"Is this how it's supposed to work? I'm familiar with this from gasoline engines, where I've used a similar device multiple times to keep the pressure relatively constant at 3.5 bar, and then adjust it between 0.5 bar and 1 bar using the fuel pressure regulator. However, I've never seen pulsations like this. It's fluctuating by an estimated 3-4 bar, and I can barely see the needle anymore."

I can't imagine that's normal; it doesn't have a constant fuel pressure.

When the line is pressurized, the pressure increases, causing the gauge needle to fluctuate even more.

"Initially, I couldn't get the second pump to seal properly; a strong stream of liquid was coming out. The pressure was lower, but the vibration has been reduced to 0.5 bar, which I would consider normal for a mechanical pump."

I'm getting some transparent tubes!

If someone tells me whether these pressure fluctuations are normal, I'll do a few more logging runs, and then that's it, I don't have time.

To be honest, I just can't manage it anymore...

However, he just won't let me go...

I checked the fuel pressure again because, in my opinion, it's injecting too little fuel.

In the initial stage, after turning on the ignition, I'm getting a reading of 0.5-0.6 bar.
So, I have one with a pre-lift pump.

I used two different watches during the exam.

The first one is shaking wildly. It probably has less internal damping and swings freely at idle, fluctuating between 3 and 6 bar. At approximately 3500 RPM, the needle swings between 6 and 10 bar.

At 2 o'clock, when I looked at the fuel gauge, I couldn't see anything; the needle seemed to be fluctuating wildly between 1 and 10.

"Is this how it's supposed to work? I'm familiar with this from gasoline engines, where I've used a similar device multiple times to keep the pressure relatively constant at 3.5 bar, and then adjust it between 0.5 bar and 1 bar using the fuel pressure regulator. However, I've never seen pulsations like this. It's fluctuating by an estimated 3-4 bar, and I can barely see the needle anymore."

I can't imagine that's normal; it doesn't have a constant fuel pressure.

When the line is pressurized, the pressure increases, causing the gauge needle to fluctuate even more.

"Initially, I couldn't get the second pump to seal properly; a strong stream of liquid was coming out. The pressure was lower, but the vibration has been reduced to 0.5 bar, which I would consider normal for a mechanical pump."

I'm getting some transparent tubes!

If someone tells me whether these pressure fluctuations are normal, I'll do a few more logging runs, and then that's it, I don't have time.

Yes, that's how it must be. To properly measure the pressure on this type of pump, you either need the original VAS 5187 or a high-quality pressure gauge from a reputable manufacturer, with a glycerin filling and properly crimped hoses.
Otherwise, you'll only get a mess.
And remember, fuel returning directly to the cylinder head can be very hot. If a hose comes off during this measurement, you'll not only look like a wet dog, but you could also easily get burned. 7.5 bar of pressure and more is also quite a lot.
The scars will remain forever.
"Manometer with crimped hoses!" No hose clamps! And no clear plastic hoses on the manometer, but hoses with a fabric reinforcement that can withstand the pressure.

Okay, now I can finally test the compression.

If it's the control side, then use the following values (otherwise, use the opposite values).
cylinder 1 23b cylinder 2 23b cylinder 3 25b cylinder 4 25b

It's completely irrelevant, doesn't it?

I've logged the air mass and the Russian limit again. I've noticed that the Russian limit is always, or at least within the range up to 2000 RPM (where it's not supposed to go), about half the value of the torque limit or the driver's desired setting.
Does that mean it operates within the Russian limit? (I don't really understand that part.) Once it goes above 2000 RPM, the Russian limit increases to 50mg, and then it activates!
PS: Attached are two logs. I tried to push it to the limit, but it's not easy when there are cars constantly in the way!

Okay, so if it's definitely below 2000 UPM, it's definitely struggling with smoke control.
But I'm curious to know whether, in the case of an AJM (presumably a type of engine or system), the charge pressure or the air mass is used as the control variable for smoke reduction?

"I've checked the vacuum side and ruled out any issues there. I've replaced the hoses from the N75 valve to the turbocharger and the pressure sensor, and one of the NEW hoses was leaking! This caused the error message "boost pressure control limit exceeded" to appear, as you can see above. The turbocharger is immediately activated with full vacuum pressure!"

I actually had 3 different LMMs, but none of them were new... I'm buying one now, and I'm not going to be ripped off.

I forgot to mention that the average fuel consumption has increased to 12 liters.
"When I drive normally, I'm getting around 17 liters per tank. I don't think I've put that much fuel in. The fuel temperature is at 70°C, which is within the normal range, and all the other temperature sensors are also working correctly."

A woman bought a new car, which is annoying because it should actually be mine.