123d: Fuel Injection & Data Logging (Reference Car)

Hello everyone,

still because of: https://community.dieselschrauber.org/en/viewtopic.php?t=25553

Can anyone tell me where I can find the specifications for the 123d?

Fuel injection quantity, air mass, boost pressure, etc.

I couldn't find anything about it anywhere on the web.

Can you inquire about something like that from BMW? I doubt they'll readily share that information.

Thank you in advance.

Best regards,

Okay, please provide the German text you would like me to translate.

Hello,

In control loops, it is reasonable to read the target value and the actual value via diagnostics; otherwise, there's no point in using OBD.

Best regards, Rainer.

dieselschrauber wrote:

Hello, In control loops, it is reasonable to read the target value and the actual value via diagnostics; otherwise, there's no point in using OBD. Best regards, Rainer

Okay, cool. Then it's not going to be that difficult after all...

You're welcome.

Best regards,

Okay, please provide the German text you would like me to translate.

I now had the opportunity to log some data... (cf.: https://community.dieselschrauber.org/en/viewtopic.php?p=189899#189899)


Unfortunately, there's nothing quite as useful as measurement block 3-8-11 in BMW vehicles. Here are the data points that I found to be relevant and have logged.

The actual air mass is always higher than the target mass (typically exceeding 1400 mg/H at its peak).


It is noteworthy that both the boost pressure and the fuel injection volume exhibit nearly identical trends relative to their respective target values. There is practically no oscillation.

Look closely; you might not immediately notice that there are actually two lines in each case.

In addition, there is a value for the current rotational moment (torque) and a value for the minimum limit, which is the lower of the smoke limit and the torque limit. I don't understand how the current torque can be above the limit... the values are clearly calculated.

Hello,

Is that engine a 2-liter, 4-cylinder, right?

Overall, everything looks good except for the somewhat high air mass. However, I think >1400mg/H at 4000rpm seems a bit too high for a 500cc single cylinder engine with 2500mbar of boost. Even BMW engines tend to overheat, so I would have expected around 1200mg/H.

Simple leak in the charge air hoses or the intercooler?

Best regards, Rainer.

Hello Rainer,

dieselschrauber wrote:

Is the engine a 2-liter 4-cylinder, right? Best regards, Rainer

Sure.

dieselschrauber wrote:

Overall, everything looks good except for the somewhat high air mass. However, I think >1400mg/H at 4000rpm seems a bit too high for a 500cc single cylinder engine with 2500mbar of boost. Even BMW engines tend to overheat, so I would have expected around 1200mg/H. Simple leak in the charge air ducts or the intercooler? Best regards, Rainer

Okay, so you mean that pressure is being lost, and the turbocharger is compensating by increasing its speed, which in turn increases the amount of air being drawn in.

That would be a problem in itself; but is it capable of explaining underperformance?

The boost pressure is being maintained according to the target value. I was actually surprised that the 2 bar of boost pressure wasn't sustained up to around 4000 RPM. However, the fuel injection amount seems to be okay, so in my opinion, the performance should also be fine.

Am I making a mistake in my thinking?

How exactly does the Register Turbo regulate the boost pressure? The swirl flaps only distribute the air between the large and small turbochargers. Is there a wastegate like in the past?

Thank you in advance.

Best regards,

Okay, please provide the German text you would like me to translate.

Bo Duke wrote:

Okay, so you mean that pressure is being lost, and the turbocharger is compensating by increasing its speed, which in turn increases the amount of air being drawn in. That would be a problem in itself; but is it capable of explaining underperformance? Bo

.

Na ja, da mit "schärferer" Ansteuerung des Laders ja auch der Gegendruck steigt, schließlich muss die Mehrmasse Luft ja angesaugt und verdichtet werden und der Lader selbst ist ja auch ein Hindernis im Abgastrakt, würde es schon etwas Minderleistung erklären. Wie"Many things are possible?"

Best regards,

Okay, please provide the German text you would like me to translate.

Hello,

Quote:

That would be a problem in itself; but is it capable of explaining underperformance?

Yes, in order to achieve boost pressure even with a leak, the variable turbine geometry (VTG) must close, or the wastegate must remain closed.
As a result, the exhaust back pressure increases significantly, while the actual air mass flow rate in the engine decreases, causing the engine to operate at an unfavorable air-fuel ratio.
"Russ, etc., are not visible due to the DPF, but the DPF itself becomes full quickly."
Since the mass airflow sensor (MAF) measures all the air being drawn in, it also detects the air that is being lost through the leak but is not available for combustion, which would explain the relatively high readings.

That can easily result in a loss of 20-30 horsepower.

I cannot provide further assistance regarding the specifics of your engine's turbocharger. However, the scenario I mentioned above is a general problem that is independent of the specific technical implementation of the turbocharging system.

Best regards, Rainer.

dieselschrauber wrote:

As a result, the exhaust back pressure increases significantly, while the actual air mass flow rate in the engine decreases, causing the engine to operate at an unfavorable air-fuel ratio. "Russ, etc., are not visible due to the DPF, but the DPF itself becomes full quickly." Since the mass airflow sensor (MAF) measures all the air being drawn in, it also detects the air that is being lost through the leak but is not available for combustion, which would explain the relatively high readings. Best regards, Rainer

Thank you for the detailed explanation. I also figured out the first part myself (see above).

I would have thought that if the boost pressure is still achieved, then everything is fine in that regard; there would be enough air available.

BUT: Due to the high compression ratio, the intake air temperature will definitely increase, which reduces the air density. At the same time, the mass airflow sensor (MAF) is essentially "telling" the engine control unit (ECU) that there is plenty of air available. This would then result in a poorer lambda value. I believe this is even measured in BMWs. A lot of things are measured around the particulate filter...

Should I start logging the intake air temperature and, if I find it necessary, the lambda value now?
If the Lambda value is measured and is less than 1, an error should actually be logged.

Ich habe gelesen, dass deutlich zuviel gemessene Luftmasse auch zu einem Fehlereintrag bei BMW führt. Ich weiß allerdings weder, was zuviel ist noch für welche Fzg. TyThat's a good point.

I don't know exactly how yet, but I probably need to have the intercooler system checked (or cleaned). With my main job, side job, and house renovations, I definitely won't be able to do it myself.

Best regards,

Okay, please provide the German text you would like me to translate.

Hello,

Quote:

so, should I log that Lambda?

if it is, for example, measured using a broadband lambda sensor inside the DPF, then yes, but if only a "calculated" value is output, it is more likely useless.

Best regards, Rainer.

Hello,

Well, as I said, the air mass is noticeably high, and an increased charge air temperature would also indicate a leak. However, I'm not sure what charge air temperature is considered "normal" for that BMW engine.

Do you have the option to check a comparable vehicle?

Best regards, Rainer.

dieselschrauber wrote:

Hello, Quote: so, should I log that Lambda? if it is, for example, measured using a broadband lambda sensor inside the DPF, then yes, but if only a "calculated" value is output, it is more likely useless. Best regards, Rainer

The lambda value seems to be coming from a sensor; a voltage value is being displayed.

dieselschrauber wrote:

Do you have the option to check a comparable vehicle? Best regards, Rainer.

I'll start looking into it.

I can't post in the upload section because of this message: "Only users with special permissions (e.g., members of the 'Blaumänner' group, or those with a 'Licensed' or 'Support' key) are authorized to create posts in this forum." Therefore, I'm posting here instead.

It is noticeable:

The reference vehicle (manufactured in May 2010) has more power.

Boost pressure build-up and fuel injection increase are slightly delayed (as of September 2007).

The air mass is quite high in both vehicles, exceeding 1,400 mg/H at 4000 RPM.

In the older model (manufactured in 09/2007), the air volume under the small loader is generally higher than in the newer model.

Can I still assume that the values do not indicate an intercooler leak?

In the 05/2010 model, the fuel injection amount is significantly reduced at higher RPMs compared to the older 09/2007 model. The newer model easily revs past 5000 RPM in third gear. In the older model, reaching 5000 RPM in third gear is not possible. The fuel injection is abruptly reduced around 4700 RPM, creating a sensation similar to a gasoline engine's rev limiter. This is supposedly also the reason why the top speed cannot be reached in the older model; achieving it would require 4800 RPM in sixth gear. The 1-series forum extensively discusses this issue.

P.S.: K-Power is a s u p e r c o o l tool!!!

Best regards,

Okay, please provide the German text you would like me to translate.