2,5l TDI AEL: unregelmäßiger Leerlauf (sägt) - Abhilfe? | Posts 16+

Hi,
"Those shock absorbers are really massive. You should loosen the tie rods yourself beforehand; that will make it easier for the workshop to do the job."

Current status:

After a two-day, intensive session in my home workshop, the service status of my A6 has finally been upgraded from 4D5 (very unreliable, not suitable for long distances) to the fantastic 1A4 (no significant defects, fully operational).

- Rear level control shocks replaced with complete non-level shock absorbers.
- Brake pads replaced.
- Tie rod ends serviced (wow, that was a job).
- Rear axle bearings disassembled, cleaned, lubricated, and adjusted.
- Transmission fluid topped up.
- Have the alignment adjusted.

It drives again with the usual quality, but the big frustration is that it required a lot of work, and the fun came at a (though bearable) cost, so something noticeable has to happen .

The only remaining active issue is the idle, which I couldn't completely fix with my modification method (39kOhm resistor connected to the electronic throttle).

- The accelerator now responds to the slightest touch.
- When approaching a traffic light with the brakes applied, the engine speed remains at 1200 rpm until the brake pedal is released.
- Depending on the mood, the idle speed can be higher, around 900 rpm, otherwise it's approximately 770 rpm.

Overall, it's still annoying, although not as much as the idling issue used to be, which has now been fixed. However, it's still noticeable. One could certainly continue tinkering with it, but it won't be truly satisfactory. Therefore, here are a few questions, as I've already done some further research using the forum's search function:

- Both for adjusting the injection quantity and for overhauling the quantity setting mechanism of the VP37 injection pump, a special key is needed to loosen the triangular screw on the quantity setting mechanism. Where can I get this key ?

- The movement of the quantity control valve was mentioned as a means to reduce the injection quantity. Does the converse apply, meaning that it is also possible to increase the injection quantity, i.e., a slight increase in idle speed?

- Who within a radius of 150km around Munich could try, using their own VAGcom software, to see if the idle speed adjustment can be done via adaptation on my AEL engine? Ordering the expensive package plus a USB adapter just on a hunch is not very appealing to me, considering the many car expenses I've had this month. However, that doesn't mean a successful adjustment has to be done for free; you could potentially amortize some of your own investment.

- Where can I find/purchase service manuals, specifically for the electronics side (wiring diagrams)? I've also seen that there's a fault database (ELSA), but you have to subscribe for a whole year, which is only worthwhile for personal use, even for technically knowledgeable DIYers. Who has access to this for viewing?

Looking forward to achieving a 1A1 status (if that's even possible with the current mileage).

Tuppie.

Hi there,

It's good that the steamer is steaming better again.

Regarding the triangular screw, there are several possible solutions, ranging from creating a custom wrench to drilling it out and replacing it with a different type. We've discussed this multiple times before, and a search should reveal more information.

Regarding the sawing idle sound, we pointed it out to you and told you exactly what you are now experiencing. Overall, I don't think it's a satisfactory solution.

Regarding VAG-COM and the interface: it's not nearly as expensive as you're making it out to be. I don't think this purchase is a waste; you'll definitely need it again. That way, the costs quickly pay for themselves. As for the other expenses, I think it's normal for a car to have certain issues after this amount of time, and that more expensive repairs might be necessary. Sometimes, a certain lack of attention to recommended repairs and maintenance can backfire, leading to a major problem that could have been spread out over time.

@joergs

Thank you for your reply. It's indeed very encouraging to see that he's managing to overcome this. Unfortunately, I can't deny a certain lack of concern regarding upcoming repairs. Aside from the sawing noise, which has appeared since the last timing belt replacement, along with difficulty starting, the entire list of issues seems to have surfaced more or less all at once.

- Ticking sounds during the fuel filling process...
- Suspected rear bearing damage.
- Auto auf Bühne ... Meister festgestellt, die Niveau-Stoßdämpfer sind total im Arsch ... Mist!
- The warehouse was disassembled out of suspicion, but then had to be completely reassembled with grease .
- only then was the faulty brake pad found...

- When changing the tires, we noticed more wear on the front tires than expected... therefore, wheel alignment is not optional, but necessary.

Everything arrived within two weeks... it was really disgusting.

'Of course, there's already a significant amount missing from the cash register. We've already had 600 euros missing in the last 4 weeks, and now another 200-300 euros... It's going to be frustrating this month.'

I know that the solution with the resistor isn't perfect, but it's a million times better than sawing. For now, it will have to do.

I'm going to check on that triangular screw now; the question is whether it will help me. Let's see. A software-based solution would be great, but well... you know.

Okay, a silly question: In every decent workshop, like ATU for example, there's usually a diagnostic tool. Should that tool, in principle, be able to perform this adaptation?

Tuppie.

It's me again .

After reading many posts in this forum, here are a few questions based on my observations:

- It appears that the newer version of the ESP is installed, with inductive sensing, not the very old one with the potentiometer (Pin 1-2: 7 Ohms, Pin 2-3: 3 Ohms). Should those values be correct?

- Therefore, the decomposition of the set of quantities nichts achieves nothing, since the inductive scanning works contactlessly? So, not like with a potentiometer: you don't need to clean the resistive path. I don't have any 'jerking' in the sense you mean, just the 'sawing' idle.

- das 10cent Tuning, soweit ich rausgelesen habe, entspricht in etwa dem Verschieben des Mengenstellwerks auf der ESP. Is that correct?

- Aber genauso denke ich rausgelesen zu haben, daß dies den Leerlauf nicht anhebt, da hier eine ganz andere Regelung greift. Is that right?

If all of that is correct, I can avoid doing all of this, and it would only require adaptation via VAGcom, assuming that works with the AEL, although no one has been able to confirm that for me yet.

Has anyone here successfully increased the idle speed of an AEL/AAT engine using VAGcom? Or could someone try it out? You can definitely note down the old value before making any changes.

Tuppie.

Hi Tuppie,


- It appears that the newer version of the ESP is installed, with inductive sensing, not the very old one with the potentiometer (Pin 1-2: 7 Ohms, Pin 2-3: 3 Ohms). Should those values be correct?

Yeah, with inductive reasoning, the values might actually be correct.

- Does this mean that breaking down the set of quantities n achieves nothing , since the inductive scanning works non-contact? So, not like with a potentiometer: you don't need to clean the resistive path. I don't have any 'jerking' in the sense you mean, just 'only' the sawing idle sound.

The turnout mechanism can simply become difficult to operate, regardless of the type of drive system used.

- As far as I can tell, the '10-cent tuning' is roughly equivalent to adjusting the quantity control on the ESP. Is that correct?

No! Absolutely not. By suggesting a 10-cent difference, you're misleading the MSG (Engine Management System) into thinking that the ESP (Electronic Stability Program) would have injected less fuel. Therefore, the MSG will inject more fuel to reach the target value (injecting a proportional amount more fuel based on the engine speed).
By adjusting the quantity control unit, you can change the actual injection amount by a constant value (independent of engine speed) regardless of the reported value.
'Therefore, 10cent is particularly effective at high speeds (and during the initial startup check), but not at idle, while shifting across the entire speed range results in a slight change.'

- But I also got the impression that this doesn't increase the idle speed, because a completely different system is in effect here. Is that correct?

Please provide the text you would like me to translate from German to English. I will then provide the translation without any explanations.


If all of that is correct, I can avoid doing the whole thing, and it really only requires adaptation via VAGcom, if that even works with the AEL, although no one has been able to tell me that yet.
Cleaning and/or slightly adjusting the component might help, especially if your idle problem is caused by gentle adjustments. This wouldn't change the LL (low load) RPM, but it might resolve the adjustment issues.

With VAG-COM, it should be possible to change the idle speed. I'm almost certain, but not entirely sure...


Has anyone here successfully increased the idle speed of an AEL/AAT engine using VAGcom? Or could someone try it out? You can definitely note down the old value before making any changes.}

I don't have an AAT/AEL available, but maybe you'll plan a vacation in Schleswig-Holstein sometime, and then I could help you...

'If I were in your shoes, I would still opt for a VAG-COM solution rather than disassembling the ESP. Although I haven't disassembled an ESP myself, there have been enough horror stories about it in this forum. On the other hand, there's also a guide by Marcello that makes it sound very easy.'

Regards,
Private.

@PrivateArea

The readings for the inductive sensing seemed a bit strange to me; I read something about 2 x 6.3 ohms. But I don't think I'll assume there's an error because of that.

So far, my motivation for disassembling the interlocking machine was to clean the potentiometer. I initially identified the part in the photo as a potentiometer, but it's probably something else. I find it hard to believe that it's stiff, because the sawing motion produces a rhythmic fluctuation in speed, which doesn't sound like a stiff interlocking machine... well, but anything is possible.

'while shifting across the entire RPM range brings about a small change,' does this mean that the idle speed could be adjusted with it, or does the preset idle speed always take control?

Hehe, the description of Marcello sounds quite simple, except for that stupid triangular screw, which I can't seem to figure out. Of course, I'd prefer a software-based solution, obviously.

From tomorrow afternoon until Sunday morning, I will be at the ILA trade show in Berlin. If anyone there has a VAGcom device and is willing to help me – for a reasonable contribution to cover expenses – please get in touch. It would be even easier if you could just email me your phone number, and I'll call you back. Alternatively, I can also access emails while I'm there.

Tuppie.

I can hardly imagine that it would be difficult to operate, sawing involves a rhythmic fluctuation in speed, which doesn't sound like a heavy-duty switch mechanism... well, but anything is possible.

Okay, imagine that the fuel rack (MSW) is difficult to move and the low-load (LL) speed is slightly too low. The engine control unit (MSG) then increases the voltage for the fuel rack. However, because the fuel rack is difficult to move, the amount of diesel injected doesn't increase, and therefore the speed doesn't increase either. So, the MSG continues to increase the voltage for the fuel rack until it starts to move. Once it starts to move, the amount of diesel injected corresponds to the voltage. However, due to the difficulty in moving the fuel rack, the voltage is already much too high, and therefore the speed also exceeds the low-load speed.
The MSG then reduces the voltage for the MSW (mechanical speed control) slightly. However, because the MSW is difficult to move, the amount of diesel fuel doesn't decrease, and therefore the speed doesn't decrease either. So, the MSG continues to reduce the voltage for the MSW until it starts to move. Once it starts to move, the amount of diesel fuel corresponds to the voltage. However, the voltage is already too low due to the difficulty in moving the MSW, which is why the speed also drops below the low-level (LL) speed.
etc. etc. etc. Well, are all the ambiguities regarding the difficulty of operation and the resulting regulatory issues resolved?


'while shifting across the entire speed range brings about a small change,' does this mean that the idle speed could be adjusted with it, or does the preset idle speed generally take control?
Since the LL speed is regulated, the MSG will always adjust the idle speed to the target value (as long as it is within the control range), and it is not possible to increase it. However, you might be able to shift the position where the MSW becomes difficult to operate, so that it does not come into effect at idle speed.


Hehe, the description of Marcello sounds quite easy, except for that stupid triangular screw, which I can't figure out. Of course, I would prefer a software-based setting, obviously.
Well, the Torx screw is probably the least of your problems. Even Aldi once offered a similar attachment in a security bit set (around 100 bits for 15 euros). So, it should be available at most decent hardware stores.

...I'm at the ILA in Berlin. If anyone there has VAGcom and is willing to help me - for a reasonable fee, of course - please get in touch. It would be even easier to plan from here; just send me your phone number via email, and I'll call you back. Alternatively, I can also check my emails while I'm on the go.
Jan6k is from around here and has VAG-COM, maybe he can help you... *hides* Hopefully he won't get angry at me for mentioning that... (@Jan, please delete this if you want, you're a moderator too).

Regards,
Private.

Hi,

Quote:

Hehe, the description of Marcello sounds quite easy

.
However, that's not the case. Without a diagnostic system, you won't be able to achieve a proper configuration, or you'll have to spend a very, very long time.

The triangular screw is the least of the problems...
- to moor
- Drill a hole in the head.
- Take off the lid.
- Unscrew the remaining piece of the screw and find a matching screw of the same length with a standard head.

Best regards, Rainer.

@private area

It's quite possible that the MSW (mechanical speed limiter) is stiff. The theory that the STG (sequential transmission control) has to 'overshoot' the MSG (manual shift gate) to move it is not entirely dismissible. It would be great if this could be proven without having to disassemble too much. I'll see if I can find a special key for it, or maybe I'll go to Bosch; with that mileage, it shouldn't be a warranty issue anymore.

@rainer k.

It can be tricky to readjust things without a diagnostic system... I know, I know. Therefore, I would recommend first trying to adjust it using software, and only then resorting to the mechanical method.

@joergs

Thank you for offering your help. And here's the important information: whoever wants to assist me with the setup should have the 2x2 pin adapter, as my C4 needs it. I have my laptop with email access with me, so hopefully someone in Berlin with VAGcom will read this in the next few days, while I'm at the ILA.

Tuppie.

Here's a brief update:

I've been to Bosch and several workshops, but so far, no one has been willing to adjust it. They claim that the same sawing noise would occur even with a higher idle speed, supposedly because an anti-stall system causes it when the ESP is worn out. No one wants to give me the dreaded triangular wrench; those who have it hide behind liability concerns, and the rest simply don't have it. Tomorrow, I'll try making my own.

What seems strange to me is that the AU (emission test) slip shows a target idle speed of 700-850, while the actual value is 725, which is at the very lowest end of the range. Today, I looked at two identical A6 cars, but in both of them, the idle speed was higher, exactly in the range where mine is also not working correctly. (For reference: the service mode of the climate control shows a value of 70(0) to 75(0) rpm for engine speed in parameter 28 on mine, while on the other two A6s, it was 75(0) to 80(0) ...).

There has to be a reason why the idle speed is so low on mine - and that's why it's stalling.

Could you please post your idle speeds (AAT and AEL models only)?

Tuppie.

Here's what I can tell you about the ATJ engine (115 hp, 310 Nm). Ours is struggling at the low end (around 800 rpm) and has a slight misfire due to an old mass airflow sensor (yes, it's a PD engine). It's time I increase the idle speed (to around 850 rpm). The problem is that I don't have the full version of VAG-COM.

Best regards, WarLord.

Hello everyone,

Driven to near despair, I must ask for your help again... After visiting 8 workshops, all of which refused to even attempt any adjustments with a variety of excuses, I went to a VAG workshop where an apprentice dared to use the original VAG 1551 device on my Audi. Let's just say he read the error memory (as always, nothing was found) and performed a basic adjustment. After that, I took a closer look at the VAG 1551 and tried to perform the adaptation myself...

Okay, MSG was selected with option 01.
With a score of 10, the adaptation is acceptable.
From 01 to 05, I tried (it didn't work; briefly, a scale appears, but then disappears immediately; the display says the value is not available or something like that).
Okay, then with 11 logins (okay).
'12233 entered, confirmed (communication freezes - data word is sent) - only turning the motor on/off helps.'

I've tried all sorts of sequences, like logging in first, then adjusting, but either the communication gets stuck on the seemingly incorrect '12233' login, or after entering the adaptation channels, it briefly displays a scale, then shows 'value not available' or something similar...

What's the reason? Does the older A6 with the AEL engine simply not have any adaptation channels, or does it require a different login?

Maybe someone here has a clue; mine is slowly running out.

Tuppie.

Everything that has a beginning also has an end .

Am Freitag habe ich, da sich kein Boschdienst dazu durchringen konnte, mir den Spezialschlüssel für die ESP auszuleihen, den Schlüssel mittels Feile und Ringschlüssel selbst hergestellt. Einmal abgeschraubt, habe ich die unselige Schraube dann auf normalen 7mm Sechskant umgefeilt. Und Well?

After cleaning the separation joint and removing the remaining 3 Torx screws, the cover of the flow meter could be easily removed. The internal components appear perfectly clean, as new. The question now was, is this part now stiff or not? To my disappointment, the shaft of the flow meter rotated absolutely smoothly with very little effort. There were no irregularities throughout the entire 90-degree range of motion. It was tested multiple times, and the vertical play was also checked, perhaps around 1mm or slightly more. In any case, there was no indication of any problems with the flow meter.

Of course, I couldn't resist, so I just loosened the three screws that hold the two sensor arms in place, just for fun, and fiddled with the arms a bit to see if they were really making contact. Well, on the other hand, why should something that's constantly immersed in diesel suffer from corrosion? So, I reassembled everything carefully and started the engine, and it runs perfectly fine.

'As a test, I removed the resistor I had temporarily installed to increase the idle speed. I restarted the engine... and now here's the thing... the idle is now at 750, and it's completely stable. It's happened before, where the engine would stall, but usually a quick tap on the accelerator would fix it. This time, that didn't work. Now, the engine only has a perfectly stable idle at a clean 750 rpm, no matter what I try.'

To date, I've already done x test drives, spent 75 minutes stuck in traffic, repeatedly checked the tachometer, and thoroughly examined all the known 'defects.'

- The sawing sound is completely gone (the best news in weeks).
- The DZR (presumably a measurement or metric) has improved by 0.2 seconds.
- The black smoke that used to be noticeable during full-throttle acceleration is now barely visible.
- The air conditioning system no longer causes the structure to vibrate when idling.

Specifically, the last two points surprised me, as they had been occurring since I bought the car and were, so to speak, completely standard.

Today, I gave my beloved car a full-body exfoliation or, rather, a really thorough polishing, and now it looks brand new again and drives just as well.

I would like to sincerely thank everyone in this forum who has contributed to the success, whether through tips or by providing useful articles, and also for sparking interest in TDI technology. After the last few visits to workshops actually added problems rather than solving them, I will probably do more of the work myself in the future.

Tuppie.

Hi Tuppie, Your success gives me the courage to continue researching my problem independently.
Something is wrong with the injection start adjustment (mechanical or hydraulic). However, I had to finish my work during the holidays because I couldn't reach two Torx screws of the ESP while it was installed. More details: /viewtopic.php?t=5866&start=48

Cool, how you simply filed off that stupid Bosch-branded screw .

Regards,
Holger.

Hello Tuppie!!

I can only say THANK YOU, THANK YOU, THANK YOU, THANK YOU!!!!!
Unfortunately, I'm a little late.... But it doesn't matter!!

I'm experiencing the exact same problem as you! I'm currently using a resistor in the accelerator pedal. But now I'm going to try the same thing you are...

I'm curious to see if it will work for me too.

Thanks, Tuppie, you've given me hope again that this problem can be solved!
I was already thinking about replacing all the piping tips just in case... But I think I'll hold off on that for now!

Best regards,
Hannes.