AEL Performance Issues: Troubleshooting Guide

Hello fellow diesel mechanics,
It's great to be among you all. You have a lot of expertise here, and I thought I would reach out with my problem.

Regarding the issue:
It's about a 2.5 TDI AEL engine. It has a power loss up to 2200 RPM. It also produces some black smoke.

Originally, the engine had a timing belt failure.
On this occasion, I removed the engine, disassembled it completely, replaced all the seals, installed a new cylinder head gasket (BJM Crafter), had the head resurfaced with new valve guides and new valves.
The default setting is also suitable.
I also disassembled and resealed the fuel injection pump, and well... the EGR valve is out of operation.

The readings at idle:
- Injection rate: 4.7 - 5.0 mg/hour.
- Air volume: 470...490 mg/m³
- Start of spraying: '62' (trend towards earlier, but it's acceptable as is).
- All temperatures are at the set point.

Actually, the engines should provide a significant forward thrust around 1900 RPM.
It won't stay with me, of course. The power delivery is slow and gradual. It seems to produce the most torque around 2200 RPM.

According to MWB 011, the boost pressure also builds up rather slowly.
1200 rpm: 0.2 bar - 4.7%
1300 RPM: 0.3 bar - 4.7%
1400 rpm: 0.4 bar - 4.7%
1500 RPM: 0.45 bar - 4.7%
1600 RPM: 0.53 bar - 4.7%
1700 rpm: 0.61 bar - 4.7%
1800 RPM: 0.71 bar - 4.7%
1900 rpm: 0.79 bar - 4.7%
2000 RPM: 0.83 bar - 4.7%
2100 rpm: 0.87 bar - 5.3%
2200 rpm: 0.95... overpressure to 1.02 bar - 47%.
2300 RPM: Set to 0.95 - 28%.

According to the turbo pressure, the car has absolutely no power at low speeds. It doesn't move forward at all. It's worse than a naturally aspirated diesel engine.

The mass airflow sensor can be ruled out.
The amount of air being drawn in always closely matches the target value. It doesn't matter if it's 100 mg/r above or below the target; any deviation is unacceptable.

I went for a test drive without the catalytic converters this time. I removed them directly before the cats and let it run freely. It didn't make any difference.
By the way, it starts producing black smoke up to almost 2000 RPM, then stops, and starts producing black smoke again from 3000 RPM onwards.

Fuel consumption is around 7.5-8.5 liters per 100 kilometers, and the maximum speed... it starts to struggle at around 200 km/h.

I've already removed the wastegate from the turbocharger. It's in perfect condition.
The small pipe on the loader is also clear. I've already cut it and installed a pressure relief valve. The pressure build-up is still slow, but then increases to 1.3 bar from 2700 rpm onwards.
By the way, all the hardware has been used for approximately 320,000 kilometers.

The compressor wheel in the turbocharger has tiny indentations on the edges of its blades. It's as if it once sucked in some solid particles that then collided with the wheel.
If I haven't mentioned it yet... the intercooler system is perfectly sealed!

And now it's your turn.
Thank you in advance.

Quote:

It's about a 2.5 TDI AEL engine. It has a power loss up to 2200 RPM. It also produces a little bit of smoke.

Check all rubber hoses, especially the bends in the intercooler pipes. Cracks are often found in the bend directly at the turbocharger and the one near the intake manifold.

Start the spraying process and check it under full load.

Check the intercooler for leaks under pressure and inspect the wastegate including the valve body.

Best regards, Rainer.

Hello Admin...
You didn't quite read my text.
The charge air system is 100% leak-free. The hose from the intercooler to the intake manifold is only 3 years old and perfectly sealed. The hose at the bottom of the turbocharger that connects to the intercooler is also fine.
LLK ist ebenfalls okay. Wir haben das Ladeluftsystem ja schon mit 1,5 Bar abgedrückt. Everything was fine.
The wastegate and everything else fits perfectly. I took it all apart and disassembled it.

The injection start time at full load is typically within a range of +/- 0.5 degrees before or after the target value. It always fluctuates slightly.

Quote:

The intercooler system is completely leak-proof!

Many people think that, but when the pressure is released at 1.5 bar, everything should really be airtight.

Does your component already have measurement block 8? Please check the limits for air mass and torque.
At full throttle, the gearbox torque must be at its lowest value.

Measurement block 8 is the one I'm referring to (blocks 000 through 014). I'll log it later.
I was already watching it from the passenger seat during the drive.
(I installed an OBD II port inside the car.)
Unfortunately, I don't remember the values anymore.

I'll also do a performance measurement using logging.
Let's see what comes out of it.


I bought the car with a 'engine failure.'
After the assembly and after driving about 200-300 km, I noticed that the idle fuel consumption was 1.9 mg/hour.
The previous owner, who had the car for the past 12 years, assured me that no one had ever tampered with the fuel injection pump.
After driving 1000 km, the ESP (electronic stability program) started leaking severely. I disassembled it and resealed it. There was no visible wear.
I then spent half an hour trying to adjust the MSW (Minimum SpO2 Waveform) settings to achieve the target value of 4.7-5.0 mg/h.
Unfortunately, it would always shift when tightening the screws. I gave up at 4.1-4.3 mg/h. Then I went into adaptation channel 001 and adjusted the device using diagnostics so that the displayed amount was 4.7-5.0 mg/h.
Ask me where the initial value of 1.9 mg/h came from.

The problem is also that the injectors are already 320,000 km old.
I actually wanted to replace the nozzle heads because they are cheap and readily available, but apparently it won't make a difference if the opening pressure is already off.

Probably new nozzles...
I've heard that the ones with the 151 hp engine for the T4 are supposed to be better... for some reason.

Okay, I took it for a spin and fully accelerated in the fourth gear, starting at 1200 RPM.
I logged data block number 8!

Up to 1800 RPM, the smoke limit determines the fuel injection amount.
Starting in 1858, UPM takes over the torque limitation function.

See the graphic:

Okay.

Unfortunately, the performance measurement didn't work.
Either he's constantly telling me that the log isn't useful, or there are errors when entering the data.
I just don't know what could be wrong with it.

das-weberli wrote:

Unfortunately, the performance measurement did not work. Either he's constantly telling me that the log isn't useful, or there are errors when entering the data. I just don't know what could be wrong with it.

It might be because you don't have a license for KPower... it would have worked with that.

I'm using software from a developer at KPower... before he released the source code.

It actually works too.
It's just not working on my TDI for some reason. For whatever reasons, it's not functioning.

Edit: It was due to my Java code.

This thing produces 149.65 horsepower / 307.90 Nm of torque .

Hello there!

I'm still trying to figure out how the slow build-up of boost pressure occurs.
Is it really possible for a K14 to simply fail after 320,000 km?
It would mean installing a new charger and having that nice pressure build-up again, or am I wrong about that?

By the way, I drove about 700 km over the past few days, and quite quickly at that.
It was usually around 160-170 [units], sometimes a bit more at 200, and on construction sites, it was about 90.
The Kassel hills and similar roads with a speed limit of 140 km/h... and about 150 km driven comfortably at 130-140 km/h.
In the end, the average fuel consumption was 7.8 liters per 100 kilometers.
With a fully equipped Audi A4 Quattro with the air conditioning turned on, that should be fine, right?

Quote:

Up to 1800 RPM, the smoke limit determines the injection quantity. Starting in 1858, UPM then implements torque limitation.

It's not that bad. I would say it's within the expected range after 320,000 km.

Best regards, Rainer.

Basically, the thrust that is known from the AEL (presumably a specific engine or system) completely disappears at around 1900-2000 RPM. It starts to gradually increase acceleration from 1800 RPM, increasing slightly until about 2300 RPM.

A friend of mine also has an AEL series engine in his Volvo V70 TDI.
When the engine is under full load and the revs reach the range of 1800-1900 RPM, you first hear the distinctive growl of the five-cylinder engine, and then a noticeable surge of power kicks in.
You can really feel it in your gut that he's really going for it.
This boost is almost completely absent for me!

Which naturally corresponds to the boost pressure curve.
I'll create another log entry about this later.


Best regards and thank you for your help.

The amount of fuel being injected is relevant to performance, and it's within the acceptable range.

The amount of fuel injected is relevant to performance, and it's okay.
Hmm, I wonder where that little bump at 1900 disappeared to.
He's gone and left.


Are you familiar with the K14 loader?