Advice

BMW engine mounding with DPF cut out and worn out injectors - how to fix it?

I have a problem that is recurring. During the DPF firing procedure, you can hear a loud engine noise, this is the sound of knocking combustion, so stated the mechanic to whom I presented it. The sound intensifies in the rev range of about 2000-2500.This occurs during load, when adding gas. On the o

Piotr Bodera – webmaster BM Cars

06 May 2024 — 3 min read

BMW_530d_Gran_Turismo_(2009)_-_rear

BMW 5 driver's question about the engine's mounding with the DPF cut out

I have a problem with a BMW with a DPF cut out engine smelling. Unfortunately, this is the model I bought and for some time now it smokes terribly when firing up. However, only on a cold engine. My mechanic says it's the fuel injectors, but I need to be sure because it's quite a big expense. What could be the reasons for the car to smoke like this? Please advise.

The problem was on the BMW 5 F07 GT, but it may also occur on other models.

BMW z wyciętym DPF — BMW 530d Gran Turismo F07 | Mattes / CC BY-SA

Response from BM Cars service regarding the problem of BMW's engine smoking with DPF cut out and worn injectors

The BMW 5 F07 GT model you own, equipped with the N57 engine, is designed to work with a DPF. The control program contained in the DDE engine controller contains sequences related to the constant monitoring of exhaust gas composition and control of DPF afterburning. If this filter has been removed and the car is not displaying Drive Failure messages, this means that the engine controller control software has also been modified.

Such a change can cause a whole avalanche of consequences also related to fuel consumption, exhaust gas quality and kicking during acceleration and when starting the engine. An additional element that has a direct impact on the so-called "kicking" of the engine is the EGR control valve, whose task is to control exhaust gas recirculation. When the engine is started, the valve should be closed. If the engine controller software has been modified, we can't be sure that this is the case. Opening the valve directs a portion of the exhaust gas to be re-combusted, ensuring the quality of the exhaust gas and the absence of kicking.

Another component responsible for the so-called BMW engine's mounding is the fuel injectors. The quality of their operation is relatively easy to check by building them out of the vehicle and checking them on a test bench and computer diagnostics of the engine. Pouring injectors can cause not only the mounding, but also serious engine damage by burning the bottom of the piston or engine valves. Your car has a mileage of about 360,000 km. Considering the modern design of BMW vehicles, it is reaching the end of its life. If the injectors have not been replaced before, then their condition is certainly close to operational wear.

We suggest you follow the steps below to remedy the problem of a BMW engine with a DPF cut out of the engine to smoke

Full computer diagnostics of the vehicle and engine. With special attention to fuel injector corrections.
Checking engine compression along with an oil test, in addition to point 1.
Checking the operation of the EGR valve.
Restoration of the DPF filter and standard DDE controller software.
Removal of other engine-related defects identified in point 1, such as replacement of glow plugs.

Without performing basic diagnostic activities, it is impossible to make an accurate diagnosis related to the problem you reported.

We invite you to take advantage of our service.