Power loss after new cylinder head | Posts 64+

A new cylinder head was installed in my BMP 2.0 TDI PD, and the screws for the timing belt were rotated back 180 degrees (previously they were 225 degrees).
Since then, I've been experiencing a loss of power in the lower RPM range, specifically between 1400 and 1800 RPM.
Before, the mail would start moving at 1400 rpm, but now it's completely stopped.
The car shifts into a higher gear later (only starting at 2300 rpm). As soon as the next higher gear is engaged, the RPM drops to 1800.
So, nothing really happens between the years 1400 and 1800.
In addition, the AGR coolers and turbocharger were replaced. The turbocharger's compressor side was checked for leaks, and the N75 valve was replaced.

Does anyone have any idea why there's a loss of power around 1400-1800 rpm?

Hi.


Yes, and what is your synchronization angle?

Best regards, Rainer.

Hi, thanks for the quick reply!

When the engine is cold:
Rotation angle at standstill: 0.0 degrees KW. Injection start: 5.9 degrees before top dead center (BTDC).
Idle torque angle: -2.0 degrees crank angle, fuel injection start: 3.1 degrees before top dead center.
Rotation angle at 2205 revolutions: -2.5 degrees KW. Feed start: 7.1 vOT.

With a warm engine:

Idle torque angle: -2.0 degrees crank angle, fuel injection start: 1.9 degrees crank angle.
Rotation angle at 2050 revolutions: -2.5 degrees. KW (likely referring to a control signal or parameter), start of feed: 2.8 vOT (likely a voltage or timing value).
Rotation angle at 2050 revolutions: -2.0 degrees KW. Feed start: 9.3 vOT.
At idle, Lambda 2.79, air mass 215 mg/H.

Hello,

Quote:

Rotation angle at 2050 revolutions is: -2.5 degrees KW, feed start 2.8 vOT

Not good, adjust the camshaft wheel until you're within +/- 1° KW. Ideally, 0°.

In addition, I would also check the vacuum hoses. You can use the VCDS actuator test to make the VTG rod extend and retract nicely.

Best regards, Rainer.

Okay, I will. The turbo is new and leak-free, and the vacuum hose fits as well.

Am I correct in assuming that a twist angle of -2 degrees favors higher engine speeds?
Does a twist angle of +2 degrees favor motor power in the lower RPM range?

Adabei wrote:

Thank you, I will do that. The turbo is new and leak-free, and the vacuum hose fits as well. Am I correct in assuming that a twist angle of -2 degrees favors higher engine speeds? And does a twist angle of +2 degrees favor motor power in the lower speed range?

Probably