Engine Power & RPM: Explained Simply

To all professionals,

I have two questions.

My diesel TDI with 115 horsepower, engine code AJM, 5-speed manual transmission.
is very weak at higher speeds.
That means it comes on based on the climate control system (not the speedometer).
at 185 km/h on a straight road with no wind.
That's all there is. Suit and tie, from top to bottom.
He runs powerfully.
I know that a diesel engine doesn't have much power at higher RPMs.
But I can't even reach 4200 RPM.
The LMM is clean (visually). The wires are definitely okay.
blank. Is this normal, or what could be the cause?


What is the deadline for submitting the application?
Ich hab mal versucht, im 4. Walked all the way to...
rote Feld, bis fast bei 4.9000 U/min. No reaction.
Regarding throttling!

I don't want to try again, unless...
Does the automatic start-up system (ASU) cause the engine to rev up to its maximum speed?

Thank you for your help.
Best regards, Holger.

Hello Holger!

Unfortunately, only for point 2, as I am not a professional.

During the emissions test (ASU), the inspector fully depresses the accelerator pedal (while stationary, without engaging a gear) until the engine reaches its maximum RPM limit. During this process, both the time it takes for the engine to reach its maximum RPM and the level of pollutant emissions are measured.

Best regards, D.

Hello D.

'I understand everything, but what I meant was...'
is when the engine does not automatically shut off.
As far as I was in the red zone, that shouldn't be possible.
'Is it not normal?' or 'Isn't it normal?'


Best regards, Holger.

Hi Holger!

My wife drives an A4 with a 115 hp AJM engine. The top speed, according to the speedometer, is 220 km/h. If you can only reach 185 km/h, something is definitely not right (what kind of car do you have?). The most common issue seems to be the mass airflow sensor (MAF). It doesn't necessarily have to be visibly dirty to provide incorrect readings. It's relatively easy to test by driving a different car. Your workshop will likely lend you one for a test drive.

"Your engine will definitely reach its rev limit, that's for sure. Diesel engines, by their design, cannot achieve high RPMs. The electronics typically cut off at around 5,000 RPM. Comparable gasoline engines often run up to 7,000 RPM or more and can sustain those speeds for longer periods. It's important that the engine is operating under normal conditions, especially that the oil temperature should be at least 80 degrees Celsius. Then you can give it full throttle even when idling without any problems; nothing will happen."

Best regards,
Uwe

Thank you all very much, especially Uwe.

I'll try that out with the LLM.

Oh yeah, I have an Audi A4 Avant.

Best regards, Holger.

Hello,

It's not always the LMM that's at fault. To get a clearer picture, simply have the measurement data blocks printed out. For the AJM, they are available in the error database.

Sure, thanks in advance.

I'll get it checked out.

Best regards, Holger.