Engine Power Loss After Head Replacement | Posts 64+

A new cylinder head was installed in my BMP 2.0 TDI PD, and the timing of the camshaft was adjusted by rotating it 180 degrees (previously it was 225 degrees).
Since then, I've experienced 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 from 2300 rpm). Once the next higher gear is engaged, the engine speed drops to 1800 rpm.
So, nothing really happens between the years 1400 and 1800.
The AGR and AGR coolers, as well as the turbocharger, were replaced. The turbocharger's pressure side was checked for leaks, and the N75 valve was replaced.

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

Hi.


Yes, and what is your synchronization angle?

Best regards, Rainer.

Hi, thanks for the quick reply!

With a cold engine:
Rotation angle at standstill: 0.0 degrees KW. Injection start: 5.9 degrees BTDC.
Idle rotation angle: -2.0 degrees crank angle, injection start: 3.1 degrees before top dead center.
Rotation angle at 2205 revolutions: -2.5 degrees. Power output: 7.1 kW. Start of delivery: 7.1% of operating time.

With a warm engine:

Idle camshaft angle: -2.0 degrees. Fuel injection start: 1.9 degrees before top dead center (BTDC).
Rotation angle at 2050 revolutions: -2.5 degrees. KW (kilowatt), start of feed: 2.8 vOT (volts open circuit).
Rotation angle at 2050 revolutions: -2.0 degrees. KW (kilowatt) power, start of feed: 9.3 volts open-circuit.
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

nicht gut, verstelle mal das Nockenwellenrad bis Du unter +/- 1°KW bist. Ideally, 0°.

In addition, I would also check the vacuum hoses. You can use the VCDS actuator test to extend and retract the VTG rod, which is a good way to see if it's working properly.

Best regards, Rainer.

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

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 speed range?

Adabei wrote:

Thank you, I will do that. The Turbo is new and leak-free, and the vacuum hose also fits. 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