Dead spot below 1500 rpm

[TonyMoneo]

Hello my fellow tractor drivers

I have an issue with my B7 2.0 TDI. In South Africa the Le Mans was a special edition of the 2.0 TDI engines (125 kW) with the BRD engine code. I bought the car second hand, and thought that the low power below 1500 rpm was just a lag issue. I browsed the forum and it seemed like the Le Mans was known for its terrible lag. So I just accepted it.

In an attempt to reduce what I thought was just turbo lag, I had the DPF removed, did the downpipe and got a software upgrade. It did improve high end power but the "lag" was still terrible.

I had the turbo, clutch and flywheel replaced over the weekend. The technician that worked on my car also drives a Le Mans. After seeing what my car should be like I am quite upset. Especially keeping in mind that his Le Mans didn't have any of the upgrades that I have done on my car - and he doesn't have the same issue at low rpm.

It is definitely not turbo lag, there must be some other issue and the best that I can describe it is a dead spot. There is absolutely NO power until you go beyond 1500 rpm.

We had the following checked in an attempt to find the culprit for the dead spot:

*Overhaul the fuel pump
*Check pulley allignment
*Replace N75 solenoid
*Thoroughly test the injectors
*Replace the boost pressure sensor
*Check for vacuum leaks
*VNT actuator is brand new so the turbo spools at low rpm

When the boost pressure sensor is removed completely, the low end power seems to be fine (but you get a significant amount of overfueling).

This is as far as my fault-finding ability goes. Any one with similar experiences or advise will be much appreciated.

Thanks!

[canadianA4B7]

Compression test done? Don't know if it wud help but just curious?

[TonyMoneo]

Tested the compression, all 4 cylinders are good :) thanks for the reply though!

[M3mPh1z]

Which city you in?

[TonyMoneo]

Johannesburg :)

[TonyMoneo]

The problem has been resolved :) :) :)

So in short what happened was the following:
The shaft of the oil pump got worn out pretty bad. This lead to an oil pump failure which gave a low oil pressure warning on the dash. As a result, no oil made its way to the turbo causing it to cease. The exhaust gas temp (EGT) sensor is situated right next to the turbo. I'm guessing things got quite hot when the turbo wasn't cooled down, but something caused the EGT sensor to fail. As a protective measure the sensor assumes the most conservative reading to prevent further damage to the vehicle. Some investigating on VCDS showed an EGT of 1000°C!! It was difficult to identify the faulty sensor because no errors were logged. After replacing the sensor the car pulled like a dream again ;)

[konarider94]

Nice update. A lot of people don't take the time to do that. It would be cool to see the diesel versions more popular in the US. Their latest scandal certainly won't help that.

[Ovi789]

All 2.0 Tdi from 2004 to middle of 2010, B7 and B8, will have the same issue. Is a well known issue and most of already have fixed the issue by making a new hole and a new shaft. For example i have an 10mm to 6mm in the pump.

Warning for those in europe, if u change just the shaft, it will wear again, and will end up with same problem or with your engine destroyed. Maine failed at 180/h and did cost me 4000euros to remake engine.

No 2.0 until middle of 2010 will escape this.

[massboykie]

Johannesburg :)

Always SO cool to see folks from the homeland posting on here! Wife and I are both from SA.

Cheers
Massboykie