My Car's Power Has Decreased and Fuel Consumption Has Increased

[balici]

Hello,

Recently, I've been experiencing some performance issues with my car, and this problem has been occurring for the last 3-4 months. I feel like the power has decreased. When I used to press the gas pedal 1 cm, I would get the response I needed, but now I have to press it 4-5 cm to get the same reaction. Additionally, fuel consumption has noticeably increased. What used to be 7.5L/100km is now up to 10L/100km.

Furthermore, while accelerating, fuel consumption increases, but when driving at a constant speed, either with cruise control or by pressing the gas pedal to maintain a steady speed, there is no issue, and fuel consumption remains normal.

The problem started around 3-4 months ago, and during that time, I haven’t made any changes or modifications to the car.

I have a VCDS cable, so I can provide the necessary data for fault diagnosis (for example, turbo pressure). I’ve also cleaned the diesel particulate filter, the MAP and MAF sensors, and the throttle body, but the issue persists.

If anyone has any insights or has experienced similar problems, I would appreciate your suggestions.

Thank you!

 

[Sasquatch]

What's the vehicles mileage?

What compression are you seeing across the cylinders?

 

[DaveD]

Hello,

Recently, I've been experiencing some performance issues with my car, and this problem has been occurring for the last 3-4 months. I feel like the power has decreased. When I used to press the gas pedal 1 cm, I would get the response I needed, but now I have to press it 4-5 cm to get the same reaction. Additionally, fuel consumption has noticeably increased. What used to be 7.5L/100km is now up to 10L/100km.

Furthermore, while accelerating, fuel consumption increases, but when driving at a constant speed, either with cruise control or by pressing the gas pedal to maintain a steady speed, there is no issue, and fuel consumption remains normal.

The problem started around 3-4 months ago, and during that time, I haven’t made any changes or modifications to the car.

I have a VCDS cable, so I can provide the necessary data for fault diagnosis (for example, turbo pressure). I’ve also cleaned the diesel particulate filter, the MAP and MAF sensors, and the throttle body, but the issue persists.

If anyone has any insights or has experienced similar problems, I would appreciate your suggestions.

Thank you!

I wonder if your EGR valve isn't closing fully when it should, so that under acceleration your engine is still drawing in some exhaust gases?
Just an idea.

 

[balici]

What's the vehicles mileage?

What compression are you seeing across the cylinders?

https://imgur.com/a/QodEe1k

140000km-86991mi

 

[balici]

I wonder if your EGR valve isn't closing fully when it should, so that under acceleration your engine is still drawing in some exhaust gases?
Just an idea.

How can I check this?

 

[CJW]

https://imgur.com/a/QodEe1k

140000km-86991mi

Wait. What? You can do a compression test with VCDS?

 

[Sasquatch]

Those number are good, round 20 bar and fairly even,

I'm presuming it's an indirect calculation based on input from various sensors...?

 

[balici]

Those number are good, round 20 bar and fairly even,

I'm presuming it's an indirect calculation based on input from various sensors...?

According to this video , when the average of the 4 values is calculated, each cylinder's value should deviate from the average by a maximum of 6 RPM. My values are: 288.5, 288.5, 253, and 290.5, and the calculated average is 280.125. The differences from the average are: 8.375, 8.375, 27.125, and 10.375, respectively. Does this mean there is an issue with my cylinders, especially the 3rd one?

 

[Sasquatch]

According to this video , when the average of the 4 values is calculated, each cylinder's value should deviate from the average by a maximum of 6 RPM. My values are: 288.5, 288.5, 253, and 290.5, and the calculated average is 280.125. The differences from the average are: 8.375, 8.375, 27.125, and 10.375, respectively. Does this mean there is an issue with my cylinders, especially the 3rd one?

I'd want to measure the compression properly before making a judgment on that.

 

[balici]

I'd want to measure the compression properly before making a judgment on that.

How can I properly measure compression?

 

[Sasquatch]

With a compression tester.

Compression may well be fine, but if you've eliminated the obvious items its pointless chasing your tail checking other stuff until you know the basic engine is fundamentally sound.

 

[Grim Reaper]

I call them Depression Tester's, because if the time has come for you to use one, you're probably going to be very depressed when you see the results.