Air Mass Too Low: Troubleshooting & Solutions

hi,
After thoroughly searching and checking for potential issues with my engine, I unfortunately haven't been able to identify a known cause for my problem.

symptom:
Air mass is constantly too low. The target value is 850 mg/m³.
The actual value is always between 765 and a maximum of 800, with a charging pressure of 1550 bar.
The actual value exceeds the target value only during pressure overshoots (maximum 1800 bar), with values ranging from 865 to 910 mg/r.
From this, I conclude that a higher airflow rate is possible and measurable.
Furthermore, I conducted several test runs using a 6 mm drill bit.
and also compared old measurement results with a new mass airflow sensor.
The same values always result.

I have checked the following points:
- The air passage between the LMM (likely referring to a mass airflow meter) and the turbocharger is blocked.
- The air passage between the turbocharger and the air intake manifold is sealed.
- exhaust and catalytic converter are clear.

mdb, I need help.

best regards, leo

Hi Leo,

Have you checked your EGR valve?
Perhaps it's not closing properly.

Regards,

Borys.

I once had an AGR.
is probably defective!

Hi Leo,

Hi Leo,

How did it break?
If only the hose has come off, then the valve might still be slightly open.
Given a boost pressure of 1.55 bar (approximately 0.6 bar more than atmospheric pressure), I'm surprised that the target value is only 850.
'On my ALH, the target value is also around 850 mg/H, but the ATL delivers a boost pressure of 1.95 bar.'
Is the EDC software still the original version?

Regards,

Borys.

hi,
The AGR (Abgasrückführung) is deactivated! (Sealing without hole).
The message is original.
I only installed the small LLK (low-loss coupling) from ACV.

Hi Leo,

hi,
Is the airflow for this boost pressure reasonable or too low?
Is it a good idea to fix the problem by increasing the pressure by 0.1 bar?

Hi Leo,

leo_b wrote:

Is the airflow for this boost pressure relatively or too low?

Unfortunately, there are no universal rules of thumb for this, because every restriction on either the intake or exhaust side(!) reduces the airflow. This means that engine A, with the same displacement and rpm, can achieve higher mass airflow rates than engine B, which has the same displacement.

As far as I know, the model-specific bottlenecks are primarily the turbocharger and the air passages between the compressor and the engine.

If you install an additional cooling coil, the colder air will increase the airflow, but at the same time, the additional pipes and the cooling coil itself will restrict the flow.

hi,
I read this article:
/viewtopic.php?t=13246
and that's how I came up with the idea that the pressure in the crankcase has become so high due to wear that a large amount of air is being expelled from the crankcase.
and therefore, the LMM must produce a value that is too low.
I'm going to test the pressure conditions at the KGE today.

Hi Leo,