2.5 TDI AEL: Slow Performance & How to Fix It

Hi,
I've had a 1996 A6 TDI-Quattro (AEL) with 170,000 km for the past 3 weeks. The car feels very sluggish in the higher gears, 4th to 6th. It does pull from around 2000 rpm, but it completely lacks the 'responsiveness' described in other reports. It feels very heavy. I took the car to VAG for a check, but they found nothing. The error memory is clear, the MAF sensor is OK, the NOx sensor is OK, boost pressure is OK, compression is OK, everything seems to be fine! An oil change was also recently done, and the values are correct.
Do you perhaps have any other ideas on where I could investigate this problem? I've read something about stuck EGR valves before. Could that be a possible cause in my case? Or are there other causes that my VAG workshop, which I don't entirely trust, might not be able to identify immediately? Unfortunately, I don't have anything to compare it to with another AEL model.

Thank you for the answers.
Thomas.

Hi, could you please close the EGR valve and then try it out?

Hello Thomas,

The so-called '' is not exactly a prime measurable quantity.
But when I take my chips out for the TÜV inspection (everything has to be in order), then, I think, I have a Dutch caravan attached. That's how splashy it is in its original condition. I don't know what you consider 'splashy' comparatively.

I'm definitely looking forward to the powerful performance of an Airbus A320 after every TÜV inspection...
Okay, it's not working in sixth gear either. Please check if the AEL (Acceleration Enrichment Learning) values are recorded with timestamps in the 'drive test' data. Then you can compare them.
Unfortunately, mine is currently in the 'timing belt heaven' and needs time to recover.

Best regards, Kai.

Hello,
I also have an AEL, and unfortunately, I only realized too late that it doesn't have enough power. How fast does yours go? Mine struggles to reach 200 [units - presumably km/h or mph].
I just took it to Bosch and had them check the fuel injection pump. I've been to several workshops already, but no one could provide a definitive diagnosis.
You could have it put on a dynamometer; that would give you a useful assessment of its performance.
Regards,
Martin.

Okay, I just found out the cause of the sluggishness in my AEL (presumably referring to an engine component). Apparently, someone had a repair done on the cylinder head before me, and during that process, the head with the injectors was likely mishandled somewhere. As a result, the injectors were compressed. This prevents the full amount of fuel from being injected.

Hi,

I'm not a fan of Topspeed. I have to admit, I don't know what Topspeed does.
I actually prefer the kick in the crossbar on the third gear when overtaking on a country road.
But he's always managed to achieve a score of 200 without any problems. The last centimeter of pedal travel.
My cargo ship transforms into a fleeing squid at 200.
Almost black 'condensation trails' near the ground, similar to those seen with the Concorde.

Well, I hope my little boat starts sailing smoothly again soon.
This weekend, I'm going to install the attachments on the new cylinder head.

Best regards, KMR.

kmrlange wrote:

...I actually prefer the feeling of being nudged in the lower back in the 3rd gear when overtaking on a country road. ...

Hello,

In our area, top speed isn't that important (or is it, Kai?). We have significantly more winding/mountainous country roads than highways.



Best regards, Bertil... who drives past an old mountain race track every day on his way to work.

Hello Thomas,

The so-called '' is not exactly a prime measurable quantity.
But when I take my chips out for the TÜV inspection (everything has to be in order), then, I think, I'll have a Dutch caravan attached. That's how splashy it is in its original condition. I don't know what you consider 'splashy' comparatively.

I'm definitely looking forward to the powerful performance of an Airbus A320 after every TÜV inspection...
Okay, it's not working in sixth gear either. Please check if the AEL (Acceleration Enrichment Learning) values are recorded with timestamps in the 'drive test' data. Then you can compare them.
Unfortunately, mine is currently in the 'timing belt heaven' and needs time to recover.

Best regards, Kai.

Hi Kai, what chip is inside the AEL?

I have now been to 3 VAG workshops, and the opinions of the mechanics during the test drive range from 'really sluggish' to 'it goes like Harry!' So far, no one has been able to identify a specific fault. Apparently, the all-wheel drive is supposedly the cause. According to the GPS, the car reaches 208 km/h on the highway, which is perfectly fine.
'But, as I said, I'm somehow missing that initial acceleration. I would like to drive a comparable AEL vehicle sometime to get a comparison.'

I had a Zafira 2.2 DTi as a rental car during my vacation, and it was incredibly fast; it was really nothing like my own car!

I haven't closed the AGR yet; it's still too cold outside for me.

Best regards,
Thomas.

Hello Thomas,

The so-called '' is not exactly a prime measurable quantity.
But when I take my chips out for the TÜV inspection (everything has to be in order), then, I think, I'll have a Dutch caravan attached. That's how splashy it is in its original condition. I don't know what you consider 'splashy' comparatively.

I'm definitely looking forward to the powerful performance of an Airbus A320 after every TÜV inspection...
Okay, it's not working in sixth gear either. Please check if the AEL (Acceleration Enrichment Learning) values are recorded with timestamps in the 'drive test' data. Then you can compare them.
Unfortunately, mine is currently in the 'timing belt heaven' and needs time to recover.

Best regards, Kai.

Hi, here's an update. Today I disconnected the EGR valve (removed the hose). Subjectively, it seems to be running better now, but that brutal power like you get with a Zafira 2.2 DTi is still missing.

I then performed a draft test under the following conditions:

0 degrees Celsius, no wind, straight road, C4 Quattro 6-speed with full equipment including leather and sound system, athletic driver, 106kg. Winter tires 205/65/15. I was in 4th gear at 1500 RPM and then accelerated. I started to decelerate at 2000 RPM and stopped at 4000 RPM. According to the climate control, I started at 49 km/h (1500 RPM), and I didn't observe the other speeds, as I was focused on the road. The time it took to go from 2000 to 4000 RPM was 12.9 seconds. Note that this was in 4th gear due to the 6-speed transmission. Unfortunately, I couldn't measure the time in 3rd gear. Are these values within a normal range? I can't find an option in the on-board computer to input the all-wheel drive information.
Best regards,
Thomas.

Hello Thomas,

I have a custom chip from a tuner who writes software for 'the big ones.' I happened to meet him by chance. These chips are specifically tuned to my engine control unit number and software version, just like the original chips. I have complete confidence in them. They provide only as much power as is technically feasible, not everything that's possible. There are no things like speed limiter changes or other nonsense included. I initially had one in my AAT, and two years later in my AEL. The difference was like night and day.
My AEL (presumably an engine) is still under construction. The new cylinder head is installed. I still need to connect the water, oil, and air hoses. Also, the fuel injectors are currently being refurbished by BOSCH. Afterwards, I'd like to do a comparison test with and without the chip tuning. Unfortunately, I won't receive the special tools from my 'friendly' contact until next week.
Okay, so there's no chance of a test run this weekend.

@Bertil
I drive past the old Dünsberg race track every day on my way home from work. Right now, I'm unfortunately in a 'T-Car,' a small BMW E30 320i. The engine revs are completely different. It doesn't really start to feel lively until 4500 RPM. But knowing that you have to downshift two gears to overtake is still enjoyable while driving.

Best regards, KAi.

Hello Thomas,

I also have an AEL with 103 kW and 6 gears. I usually drive very fuel-efficiently, and on average, over the past 3.5 years, my average consumption has been 6.2 liters per 100 km.
The car reaches a speed of 200 km/h, but:

Recently, I had to drive across Germany with a very heavy and large trailer. It was wider than my car and about 3 meters high (creating significant wind resistance!). Throughout the entire journey, I drove at 80-100 km/h in 5th or 6th gear, pushing it pretty hard. Subjectively, towards the end of the 1300 km trip, I felt like I could have been in 6th gear more often than at the beginning. Oh yes, both the trailer and the car were fully loaded from start to finish (4 people, luggage, trailer completely full). The fuel consumption was 11.5 liters per 100 kilometers.

Only after I had driven again without any issues did I notice that the engine was running wild, especially at or above 2000 RPM. This wasn't the case before. Sometimes, even a slow driver like me has to press the accelerator .

One thing is certain, it's a world of difference! The acceleration is *much* better than before. My guess is that the turbocharger was clogged up previously, and that the intake and exhaust were also dirty. I haven't changed anything related to the EGR system. The car now has approximately 295,000 km on it.

What do you think about that?

Hi, what should I say about that? That's great for you and your Audi .
I'm actually quite a fuel-efficient driver myself (around 6.7 liters per 100 kilometers), and I don't have the opportunity to drive fast on my daily commute to work either.
I haven't driven the TDI on the highway yet either, but I once had a Kadett 1.7D that I also had to break in before it ran properly.
I once had a chip installed that was so extreme I removed it after only 3 days. The entire crankshaft vibrated intensely when accelerating from low speeds, but the car had incredible power. One night, I was driving on the bypass road and accelerated from 175 km/h to 215 km/h in 6th gear; it happened incredibly fast. It could have gone even faster, but the road didn't allow it!
Someday, I'll get a chip from a reputable tuner.
Best regards,
Thomas.

@TDI-Quattro

'Try doing the DZT (Dynamic Torque Test) in 3rd gear; anything from 6.5 to 7.2 seconds should be normal. I'm not sure why you would test it with 4th gear on a 6-speed transmission... if I had tried it, I would have a reference point.'

Tuppie.

@TDI-Quattro

'Try doing the DZT (Dynamic Torque Test) in 3rd gear; anything from 6.5 to 7.2 seconds should be normal. I'm not sure why you would test it with 4th gear on a 6-speed transmission... if I had tried it, I would have a reference point.'

Tuppie.

Hi, I was wondering if you're using the 4th gear because the gear ratios are different in the 6-speed transmission?
I'll try using size 3 sometime soon. But right now, I have 225/45/17 tires on, is that a problem?

@TDI-Quattro

'Try doing the DZT (Dynamic Torque Test) in 3rd gear; anything from 6.5 to 7.2 seconds should be normal. I'm not sure why you would test it with 4th gear on a 6-speed transmission... if I had tried it, I would have a reference point.'

Tuppie.

Hi, I was wondering if you're using the 4th gear because the gear ratios are different in the 6-speed transmission?
I'll try it in the 3rd gear sometime soon. I currently have 225/45/17 tires on, is that a problem?

It wasn't stated anywhere, so I used the 3rd one. In principle, if you entered the data correctly, the 4th one should also work, as it simply uses different numbers, but the deviation can be recognized in the same way. However, if I already have the experience values in the 3rd one, it's more convenient to compare with that. Or I would have to repeat the test in the 4th one... which is rather unlikely .

Tuppie.

@Tuppie
Sure, I'll test your numbers for the third time. I'll get back to you later!
Greetings.
Thomas.