Defective Switch: Can It Be Hauled?

I'm planning to buy an Audi A3 TDI AHF (110 hp), manufactured in 1998, this weekend.
I might be able to get it for a very good price, but the problem is that, according to the owner, it doesn't start (fault code related to the mass airflow sensor).

So far, with the VP37, I've always been able to get the vehicle running by towing it.
Was do you think, was it just luck, or what are the chances that it could work out here too?
It sounds a bit like guesswork, but maybe someone has more experience in this area than I do.
I would then clean the pump at home, following the instructions.


It's a 200km drive to get there, and I'm unsure whether to drive with a trailer or get red license plates instead.

So far, I'm leaning towards a drop-top.

Best regards,

Hi Klaui!

First, use VCDS to read the error code precisely. If you're still sure you want to make a deal, then take it home with you on a trailer.
It's possible that the KW screw has a problem, the injection timing is misadjusted, and that's why it's not starting.
200km later, it might have been the end of the bargain.

Best regards from Munich!

DieselBär30x wrote:

Hi Klaui!

I really hope you made a typo.

I thought the "killer screw" problem only affected the 90hp engines, or the AFN engine occasionally?
The current owner says that the car was previously at Audi, and they wanted to install a new ESP (Electronic Stability Program) system.
I will call again tomorrow to confirm if it is indeed the MSW and to find out exactly what error codes are stored in the system.

I just bought a hammock, otherwise I would have gotten too hot.

I'd like to refer to this thread.
I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

I'm going to take a torque wrench and a 19mm socket to check and tighten a loose screw.
VCDS will also be present.

Yes, Klaui, I have user dyslexia, you know.

Generally, the 1Z/AHU (90 hp) engines are very susceptible to the KW screw problem. The AFN and similar engines are affected less, but it happens more often than rare .
"Always check the crankshaft pulley and bolt on VAG engines, especially if there are corresponding symptoms and an ESP (electric steering pump) is present in the timing drive system."

Even my first car (a 1987 Passat with a 70hp diesel engine - I can't remember if it was a CY model...) was severely damaged shortly after I sold it to the next owner (a neighbor), despite my having taken perfect care of it - and without any modifications! He had the timing belt replaced by a workshop, even though I had already replaced it myself, and then he had them do it again. Coincidence or not, the engine was beyond repair after that.

Therefore, as before: Use VCDS to read out the data and don't let your own "crystal ball" be obscured by more than three walls.

Best regards from Munich!

..also EDIT: With VCDS, you can check if the problem is actually related to the MSW (Engine Control Module), whether it has been tampered with, and finally (if you manage to get it working), use the timing checker to adjust the crankshaft pulley.

I will report back, otherwise it was a nice trip .
Thank you for the hint .

I called again today.
He told me that a local repair shop tried to fix it, but they messed with the "MSW" – I suspect they were actually working on the "RSW".
Is it even possible to achieve a proper alignment again after cleaning the MSW (Multi-Station Welding machine)?

Best regards,

Yes, regarding the values of the start-stop voltage during the interlocking system test.

Can you display the measuring blocks from the engine control unit using VCDS?

Best regards, Rainer.

Basically, yes. We have target values, and you can see the actual values and error entries using VCDS before you buy. With a little patience and luck, the mechanical adjustment can also be achieved.
However, during price negotiations, I would assume that the ESP is broken, or that the engine will rev uncontrollably and fail after the next adjustment.
hg
Herbert.

Thank you very much.
When negotiating, I'm already assuming there's engine damage.
Or do you seriously mean that it would happen like that ?

"Shit happens."

The 1.9 TDI engines from the A3 are no longer affected by the "killer screw" problem.
The central screw is thicker, the KW wheel has a larger contact surface, and the flat area on the KW stub is much larger.

Unfortunately, the AFN engines are affected to the same extent as the 1Z and AHU engines because they have the identical crankshaft design.
I just did that to my Sharan, which I use as a cargo van.

I checked it thoroughly when I bought it today, and it's a perfect fit.
According to VCDS, the RSW voltage is 0.7V, but it should ideally be between 1.2V and 1.7V.
I hope they only worked on the RSW (Rotary Screw Welding) unit and didn't disassemble and incorrectly reassemble the MSW (Modular Screw Welding) unit.

Hi,

Quote:

...should actually be between 1.2 and 1.7V. ....

refers to the idle state. You probably see the 0.7V when the ignition is on. It's somewhat borderline, but not necessarily a problem.
What exactly does the error memory say, and what do you see in block 19 when the ignition is turned on, and in block 1 when starting the engine?
hg
Herbert.

Unfortunately, the error memory is empty.
I've now set the MSW (Main Supply Voltage) to 0.760V.
The engine still won't start.
In the Mwb 19 specification, the minimum voltage is 0.760V and the maximum voltage is 4.5xxV.
"Interestingly, in Mwb 1, neither the speed nor the mg/h of fuel injection changes."
Both are at 0.
Coolant temperature is plausible.
What I've noticed is that when I try to start the car, the instrument cluster flickers and the daily mileage counter resets to zero.
Now, I'm going to check for any faulty ground connections.
Relay 109 is working correctly.

Würde ein defekter NW-positions Geber in Fehlerspeicher stehen? Actually, yes?
Best regards,

klahaui wrote:

Would a faulty NW-position sensor store a fault code? Actually, yes?

No. The engine doesn't have one, actually.

I think there's something else wrong, and the search for the relay is heading in the right direction.
If the engine control unit is not tampered with, there would be something in the error memory.

Best regards, Rainer.

Sounds plausible .
According to the previous owner, the MSTG is untouched.
Theoretically, something should be mentioned in the documentation, besides the fact that the MSTG is activated when the system starts.
no electricity.
The positive and negative connections from the battery are at least okay.
Relay 109 is engaged, which means it's receiving power.
Unfortunately, I don't have a wiring diagram to help me understand it better.