Wave Acceleration ARL: Benefits & Applications

Once again, I'm having a small issue with my Leon ARL at 65,000 km and could use your help.

'When accelerating from the 5th to 6th gear, around 1500-1900 RPM, I experience noticeable jerking or a wavy acceleration pattern.'
Unfortunately, I haven't been able to find what I was looking for using the search function.
I already sealed the EGR valve because I initially suspected it was the cause, but it turned out not to be the problem.
Yesterday, I collected some log files, and I need your help analyzing them because I haven't been able to identify anything myself.

My suspicion leans towards a problem with the PD (positive displacement) pump or a faulty tandem pump, or possibly just pressure surge. However, I consider the latter to be less likely.

Here are my three data logs, all recorded while in the 5th and 6th gears. Please don't be surprised if you see a small surge of power recorded in some of them.

I also hope that you like the materials we used.
'Thank you in advance.'

g1om wrote:

I experience noticeable jerking or a wavy acceleration when accelerating from the 5th/6th gear, specifically in the range of 1500-approximately 1900 revolutions per minute. Unfortunately, I haven't been able to find what I was looking for using the search function. I already sealed the EGR valve because I initially suspected it was the cause, but it turned out not to be the problem. Yesterday, I collected some log files, and I need your help analyzing them because I haven't been able to identify anything myself. My suspicion leans towards a problem with the PDe's or a faulty tandem pump, or simply an overpressure surge in the charging system, although I consider the latter to be rather unlikely.

LD fluctuations never cause "hard" jolting, but at most lead to mild surging effects.
However, we can rule this out because the blurring remains constant above the engine speed (rpm) starting from 1400 rpm.

The cause of the engine misfire is likely related to the diesel fuel supply system...

In which two values will the distortion be visible in this case?
Is that normal?
When you talk about supply, are you assuming that a tandem pump might be the solution?

g1om wrote:

In which two values will the blurring be visible in this case?

/viewtopic.php?t=12979 (Download, MWB sheet)

Quote:

When you talk about supply issues, are you assuming that a tandem pump might be the problem?

In principle, anything between the tank and the high-pressure pump (PDE) could cause it, where air can enter or fuel pressure can be lost.

Okay, unfortunately, I haven't become much wiser from the other text, but...
I'm going to take a closer look at my fuel sender tomorrow, as I had a heater installed a few months ago, and I want to make sure everything is working properly.
I will report back as soon as I find something.

Okay, unfortunately, I haven't found anything wrong with either the fuel level sensor, the distributor (DiFi), or the 'frog' (presumably a component).
still other places
To rule out a problem with the tandem pump, I would like to try restricting the return flow.
Are there any damages caused by such a measure in the case of an intact TP (presumably referring to a 'traffic participant' or similar)?


I found another oil leak on the coolant hose at the inlet of the heat exchanger. We've seen this before, and it caused a wavy acceleration pattern.
Personally, I'm not convinced that this is the root cause.

g1om wrote:

To rule out the tandem pump, I would like to try "narrowing" the return flow once. Are there any damages caused by such a measure with an intact TP?

As far as I know, no. Then, the return diesel is redirected back into the supply line via a pressure relief valve instead of going to the tank, and it's circulated within the system.
However, the diesel temperature then increases significantly because the cooled supply from the tank is no longer available.

Quote:

I found another oil leak on the LLD hose at the inlet of the heat exchanger. We had a similar issue here before where it caused a wavy acceleration pattern.

?? Do you have another link to that topic?

The cause of this was not determined, but we are heading in the right direction.

/viewtopic.php?t=14588&highlight=flutter

How did you actually get the fuel supply?
Based on the official documents (MWB) or based on my statements?
Could it also be the PDEs? (MWB 23???)

The engine has power, starts well, and otherwise seems fine until you get on the highway and are driving between 1500 and 1900 RPM with some load, typically in 5th or 6th gear. I also experience this issue when using GRA (presumably referring to a specific driving mode or system).