Performance issues A4 Avant 1.9 TDI - 90hp AHU 1996

Hello everyone,

I'm relatively new here and I'm having a problem with a friend's car. His Audi A4 Avant with 1.9TDI engine won't go at all. The maximum speed is just over 3000 rpm and it drives like a tractor... :-(

I connected the car to VCDS and found the following error...
[i]
Address 01: Motor Label file: RKS-906-018-AFN.lbl
ECU Part Number: 038 906 018 R
Part and/or Version: 1.9l R4 EDC 00SG 1632
Coding: 00002
Operating Number: WSC 06325
VCID: 254598D8BFFA27B

1 Fault found:

00522 - Temperature sensor for coolant (G62)
30-10 - Open circuit / Short to earth - Intermittent

Readiness: Not available
Okay, I understand. Please provide the German text you want me to translate. I will translate only the readable text, leaving any HTML tags, BBCode tags, and URLs as they are.
Furthermore, I took a test drive and logged the data...it appears that the turbocharger is indeed faulty, as the boost pressure is no longer being built up. The readings for the 3, 8, and 11 measurement gaps were logged...

Hmm, I'm not very impressed with mechanics here, especially since I live in France, and they don't really seem to put in any effort...it seems that some are overwhelmed by the engine or want to install a complete engine right away...of course, all without a diagnosis or proper test drive!
[I]I would be very grateful if you could take a look at the file and give me some feedback.[/I]
Edit Admin: Data cleanup completed.

Thank you,
Flo

Hi,

I had a similar problem with my ALH, nothing worked above 110 km/h. There were no errors in the fault memory etc...

The also had a faulty turbo and wanted to install a new one for me.

The garage in my village then agreed to open the hood: in my case, it was a broken vacuum hose that was causing all the problems.

Maybe you could take a look, I remember it being "on the way" to the engine control unit.

Viele Grüße,
Marco

Okay, please check if the VTG adjustment actually moves and if there is vacuum at the VTG vacuum connection. The vacuum should already be present at idle. This is easily checkable/palpable when the hose is disconnected.

When the vacuum hose is connected, the VTG linkage should move approximately 10mm.

If hissing or whistling sounds occur during acceleration (i.e., as soon as the boost pressure is built up), this could indicate a leak (e.g., a crack in the hose) in the ducting between the turbocharger, air-to-water cooler, and intake pipe.

Definitely replace the faulty sensor.

Post the results. Then we'll proceed. If there should be no vacuum, please first check the ducting for damage.

And please post the log files as they were saved by the program.

Hello,

I've taken the liberty of extracting the (small) useful parts from your log and modifying the graphics.

Please, in the future,
/viewtopic.php?t=12979
should be considered when creating logs. Also, converting to .XLS with KDataScope is unnecessary.

Your log shows insufficient air mass, even though an attempt is being made to build up boost pressure.
Therefore, the injection amount is limited, and the car doesn't move forward.

Please check the following:
- The air mass sensor is the
[b]correct[/b]
and ok? Does the VTG adjustment work perfectly? Temporarily replace the LMM with a similar one (VAG part number identical, including the letters at the end!) for testing.

- Does the catalytic converter rattle when tapped? The catalytic converter can come loose and tilt within the housing, resulting in almost completely closed exhaust with a corresponding low air mass flow.

- Is the hose to the pressure gauge of the air compressor ok? Without pressure, the air compressor pressure is limited to 0.6 bar... See: TDI underpressure venting: /viewtopic.php?t=3101

Best regards, Rainer

Oops, I completely forgot about the cat. Now he has something to do.

I would suspect a wastegate in the A4. The part number for the control unit is not AFN

According to the original poster (TE), there should be an ALH (which I believe owns a VTG).

ALH would be a Golf/Bora engine, not a long-stroke engine like in the A4 I would initially consider this to be incorrect

Okay, I'm convinced, a 90hp diesel in the A4 B5 will be a 1Z or AHU engine

[quote="klahaui"]Persuaded, a 90hp diesel in the A4 B5 will become a 1Z engine 99% of the time [/quote] For a 1996 model, it's definitely a 1Z engine 100%. If it were newer, the AHH engine might also be an option, but not in this case.

Maybe. I think in 1996 it will be A4 - B5 and therefore Longstroke = AHU. 1Z was the counterpart in the transverse engine installation :wink:

Would the part number speak for itself? As far as I remember, the 1Z still had the 028's.

Okay, here's the translation, keeping the HTML tags, BBCode tags, and URLs intact:

Hab meins schon überarbeitet
Könnte wie gesagt auch der AHU sein.
Denn noch beides Wastegate wie Mulle schon sagte.

038906018R is the control unit for the AHU, at least according to AKTE
But the 1Z was also available in the B5, as I had one myself.

EDIT: The AHH was available from 98.

There was a problem with the identification numbers, that's true. Did they run out of numbers or something?

Also, der 1Z Motor wurde auch im Audi als Langmotor eingebaut. Als die Motornummern ausgegangen sind, wurde daraus ein AHU. Für das Baujahr 1996 kommen AHU und AFN in Frage. Aber vielleicht kann Charmillo bestätigen, welchen Motor er tatsächlich hat?
hg
Herbert

Hello everyone,

First of all, thank you for your help. I made a mistake, the A4 has an AHU motor... (ALH was my old Ibiza... )

I will check the VTG this weekend and possibly also check the LMM. Unfortunately, I don't have a suitable LMM available... Hmmm, I will therefore check the diode test...

/viewtopic.php?t=3347&highlight=Diode

Best regards