Caddy performance issues

I have a Caddy BJB with 105 horsepower that has absolutely no power.
The owner has already tried the following.

- new diesel filters
- AGR closed.
- Exhaust system installed and used with a turbocharger.
- Camshaft checked for wear.

"But it all yielded no results. I once did a logging run, but besides the fact that the LD has a massive overshoot and then drops off significantly, slowly recovering (probably due to a heavy VTG), I didn't notice anything else." Limits are all as they should be, including the injection duration.

Even in the MWB 23 report, I found nothing to indicate a fuel shortage.
The dataset is also the original one.

I also checked the pressure from the tandem pump; it's reading 2.5-3 bar in the low gear.
At 4000 rpm, the pressure is 7.5 bar (target value).
While driving, I also have a maximum of 7.5 bar. I made a video, but unfortunately, the scale on the pressure gauge is unreadable.
However, if I clamp the return hose on the LL (likely referring to a specific piece of equipment), the pressure increases up to 10 bar. That would suggest faulty O-rings, but it also starts immediately even after a long period of inactivity.

Even though I'm giving it full throttle, it struggles to reach the rev limit, and I initially thought it might be due to a restrictive exhaust, but the owner has already ruled that out.

Has anyone experienced a significant loss of performance due to defective PD O-rings? It could be worse than an SDI.
Does anyone have any comparative data on fuel pressure while driving? Specifying the target value for VW at LL (low load) and 4000 rpm is not ideal.

I'm not sure where to start, whether it's O-rings, a tandem pump, or something else entirely.

The .rar files contain logs in xlsx format.

Hi,

How did the error occur? Are the correct PD elements installed, and are they properly configured? If the engine has the mileage mentioned, then nothing should have been tampered with...
Why does the boost start so early, considering the boost duration already ends in overboost territory? Have there been any attempts at flashing or tuning the vehicle? What is the fuel temperature in the corresponding measurement block?

Best regards, Rainer.

An elderly man is driving a car, and he thinks it's normal (this has been the case since he bought the car).
Now, his son, who also went through all the preliminary tests, noticed it.
That's why I can't say whether these are the correct PD elements or if they are installed correctly.

The fuel temperature was 55°C after the test drive, with an outside temperature of 10°C.

I compared the file with an original, and it is completely identical.
I just double-checked the SB maps, and they match the log.

I tried it with a tuning file today, but it's still not better.
I need to postpone this to a later date, as I am currently experiencing significant health issues (knee problems).

But if anyone has any ideas, I would be grateful for any suggestions.

As I said, I would check the PD setting. What is the maximum current injection amount displayed by your diagnostic system, in mg/hour?
Perhaps the conversion to injection quantity is going wrong due to faulty sensor readings or software errors... I don't remember off the top of my head whether the injection angle shown in the log is correct, as there are significant differences depending on whether the DPF is present or not (different PD units).

Best regards, Rainer.

With the original software, I get 45mg/H.
With the modified version, I'm getting around 55mg/H.

It largely matches the data in the file (DM quantity curve).

I also suspect that the previous owner may have made some changes regarding the PD (powder deposition) elements, perhaps by installing a different nozzle or using different components. The car is from the Czech Republic; maybe they combined three cars into one.

I'll definitely have to check that out when I'm back on my feet.

"45mg/h @ 4000rpm would be approximately 125 horsepower, not 105 horsepower. Is that really what's shown in measurement block 1 at that RPM? Or was it within the range of maximum torque? Perhaps my "max" statement was a bit unclear; I meant the injection amount at maximum power output." The engine shouldn't produce any soot if there's not enough fuel, is that correct?

Best regards, Rainer.

45 mg/H is the maximum value it displays, which corresponds to the highest torque.

It doesn't produce any soot either. I usually only log the duration of the pumping process. I only briefly checked what the MWB 1 displays as its maximum value.

At 4000 RPM, it produces 232 Nm of torque, which is approximately 38 mg/H according to the original specifications.
With the mod, I then measured approximately 51 mg/H at 4000 liters per minute.

Are you sure that 45mg/H should correspond to 125 horsepower?

chli1976 wrote:

Are you sure that the 45mg/H should be 125PS?

Yes, based on a rough estimate, it's already above 4000 rpm. 38 mg/H at 4000 rpm is approximately the expected value for 105 horsepower.

Best regards, Rainer.