Audi A4 TDI Quattro Problems: Common Issues & Fixes

Hello,

I received the vehicle with approximately 6,000 kilometers on the odometer (previously a demo car), and I immediately had the impression that there was a performance issue.

After several visits to the workshop, and in consultation with Ingolstadt, a performance test was carried out.

All measurement blocks supposedly okay, but the calculated torque within the measurement block is too low.

The mass airflow sensor (MAF) and the boost pressure should also be fine.

The performance test results showed 181.5 horsepower (compared to the standard 180 hp) and 338 Nm of torque (compared to the standard 370 Nm).

According to the dealer's statement, it is within the tolerance range.

According to the manufacturer, the fuel injection pump will probably be replaced.

What do you think about it?

Regards,
Michael.

Hello,

The information you provided is insufficient to make a statement about a potential problem.
Given that your measured torque is significantly lower than expected and the maximum torque likely falls around 2000 rpm, you should record boost pressure, air mass, and fuel injection volume using a suitable tool.
That is, the performance under full throttle and acceleration across the entire RPM range.

Does the engine exhibit any other unusual characteristics, such as black smoke, delayed turbocharger boost, misfires, etc.?

Which parts have already been replaced during your visits to the workshop?

Best regards, Rainer.

Hello,

Unfortunately, I don't have the ability to read the control units myself. This has always been done at the workshop, and they also transfer the data to Ingolstadt.

Currently, only the mass airflow sensor (MAF) is being swapped out.

'There is no noticeable lag or hesitation, but the acceleration in 5th gear (Tiptronic) is very sluggish, and overtaking maneuvers on country roads are also very slow.'

When starting, it takes a moment to get going, which I assume is related to the weight and turbo lag.

I once had a chip tuning device installed, and it made a strange noise around 2000 RPM, like something was leaking pressure. However, the noise disappeared after I removed the chip tuning device.

When accelerating from a low speed, around 20 km/h, you often hear this typical 'cold start knocking' sound, but it can also be perfectly normal.

I also deactivated the EGR valve once, and initially I felt like the airflow was better. However, now it doesn't make any difference anymore.

Thank you in advance for your help.

Michael.

Hello,

The problem has now been resolved. After replacing the fuel injection pump, the torque values are also within the acceptable range.

Michael.