Lack of power in Fiat Marea TD 100

Hello,

This is my first post in this forum. I'm a complete novice when it comes to diesel technology.

Here's the translation:

'I'm experiencing a problem with my car (Fiat Marea TD 100, first registered in 02/98, 170,000 km). It's been losing power for some time. There's not enough power when starting, and it also lacks power in the higher RPM range. The maximum speed is barely reached.' It seems like the engine 'doesn't know' anything about the turbocharger; it only delivers its full power for a few seconds occasionally.
Under full load, there is a noticeable amount of dark smoke, and the oil consumption is approximately 1 liter per 10,000 km (but it was almost zero until around 150,000 km).

What has happened so far:
Air mass sensor cleaned with brake cleaner.
Air filter, mileage: 7,000 km. Diesel filter, mileage: approximately 27,000 km.

Hoses (pressure side) inspection: no faults found.

Diagnosis Workshop I: 'The turbocharger is slightly stiff.'

Diagnosis Workshop II: Performance test results: approximately 10 kW of power is missing, the turbocharger spools very late, the power delivery is consistently increasing and decreasing, suggested next steps: check the fuel injectors; the mass airflow sensor is unlikely to be the cause.

Diagnosis Workshop III: Error code indicates: Mass airflow sensor, value too high. Suggestion for next steps: Replace the mass airflow sensor.


In which direction should I continue the search?

Hello,
What does the workshop mean when they say 'the turbocharger is slightly stiff'?
Has the vehicle primarily been used for short trips, resulting in a full catalytic converter due to excessive soot?
Best regards,
Günther.

Hello,

If you're a beginner, is it okay to ask how many attempts it took you to answer the registration questions?

Or are those the assumptions of your colleagues?

Best regards, Rainer.

Hi,

That's a bit too little information about the car...

But I think I can remember the engine. It's a 1.9-liter CR engine with a VTG turbocharger.
Since VW isn't the only manufacturer experiencing issues with the VTG (vaneless turbocharger), it's likely that you're also experiencing this problem. Therefore, Workshop 1 was spot on with their diagnosis. Workshop 2 is on the right track, but initially heading in the wrong direction, and Workshop 3 is completely off course.

Sure, here's the translation:

"Here's a small tip:"
Search function: "stuck VTG"

Hello,

Thank you for the initial suggestions. That was really super fast.


The answers, in order:

1. The car is mainly used for short trips from Monday to Friday, and on weekends it's driven twice, each time for 400 km. (I commute home on weekends).

2. I'm not entirely sure what the workshop meant when they said 'slightly stiff.'
The invoice stated: 'Turbocharger checked for play; runs slightly heavy when warm' and 'Fuel pressure OK (0.3 bar)'.

3. This was the first attempt.

4. According to my records, it's a 1910 ccm engine that is not a common rail (I believe common rail technology was introduced with the JTD series at Fiat).

5. The turbocharger with wastegate pressure control valve is a GT 15 model from Garrett.

Does anyone have a suggestion on how the search should proceed?

Hello,
You should check the boost pressure and try to figure out why it might be a bit low (possibly due to smoke).
If it's the initial nozzles, it might be worth considering having them checked (or replaced?) as smoking also indicates a lack of performance.
Best regards,
Günther.

If the turbocharger is warm and sluggish, it's likely that there's also a lack of boost pressure.

Does it only smoke when accelerating, or also when running at full throttle continuously? Possibly have it observed by someone following behind.

And have the boost pressure measured, ideally recording the difference between the target and actual values during one or more full-throttle acceleration runs in 3rd gear. Gang or higher.

Has the EGR valve ever been checked?

Hello,

And once again, thank you for the quick responses.

There are still some of the original nozzles.

It smokes even when running at full throttle.

'Boost pressure was measured during the performance test and found to be within the acceptable range. However, the data was not recorded. Here begins one of my real problems: I haven't been able to find a workshop that is truly knowledgeable in diesel technology and that can also read the engine control unit. The engine control unit is from an Italian manufacturer, and neither Bosch (I have already visited 3 Bosch workshops...) nor ATU can read it.' This makes it impossible to compare target values with actual values at this time.

@Roger: Do you think the EGR valve might not be closing properly and is constantly mixing exhaust gases into the intake air?


I don't understand why the engine sometimes seems to 'remember' its turbocharger, and most of the time seems to 'know nothing' about it.

I would appreciate any further assistance.

Greetings.
Stefan.

Quote:

@Roger: Do you think the EGR valve might not be closing properly and is constantly mixing exhaust gases into the intake air?

AGR-Fachartikel:
(or)
AGR Technical Articles:
Okay, I'm ready. Please provide the German text you want me to translate.

Either that, or the loader won't be able to reach its target pressure anymore. However, the diesel control system should ideally detect this and compensate for it by reducing the amount of fuel injected.

Therefore, the AGR deserves a critical examination.