V50 Engine 2.0D : - Rough acceleration when engine is warm

darlik · Apr 23rd, 2022, 16:00

Hello guys,
I'm new to this forum and I need your help. I have a 2008 Volvo V50 2.0d 136hp. The car has a problem during acceleration between 1500 - 2100 RPM. The whole cars is shaking back and forth when the pedal is normally pressed. If I fully press the pedal there is no problem. The problem is only present in this RPM range and when the cooling liquid temperature is above 60 degrees. When the engine is cold there is no problem.

It all started after the turbo failed. I've managed to turn off the engine by engaging 5th gear and releasing the clutch. After that the turbo was replaced and it turned out that one of the injectors was bad too. The faulty injector was replaced. After 600km this problem appeared. After that all injectors were inspected again and they are fine. There are no error codes or anything. It's not the pedal position sensor because the problem is present during cruise control acceleration too. Fuel filter is replaced too. I have no clue what to check next. I know that the fuel pressure should be different when the engine is cold and when it is warm, but I don't know the exact numbers to make a reference.
I hope someone can help me.

Cheers!

passenger · Apr 23rd, 2022, 21:19

Wish you have some code reader.

I would go for EGR valve. Try to disconnected EGR valve (just connector) and try it. Volvo VIDA would solve problem. You could see movements of EGR

darlik · Apr 23rd, 2022, 21:33

Quote:

Originally Posted by passenger

Wish you have some code reader.

I would go for EGR valve. Try to disconnected EGR valve (just connector) and try it. Volvo VIDA would solve problem. You could see movements of EGR

Thank you!
I've tried disconnecting the EGR valve but there is no difference. With a standard diagnostic tool there are no error codes. I will find somebody with a VIDA and report back if we find something.

passenger · Apr 23rd, 2022, 22:45

Huh no idea more sorry.

Quick google put me on this forum and this thread

https://www.volvoforums.org.uk/showthread.php?t=297220

darlik · Apr 29th, 2022, 17:47

Hello again.
We resolved the issue. There is one-way valve on the fuel return pipe and it was blocked. It is located under the y-shaped throttle body and it is part of the fuel temperature sensor assembly. The whole assembly needs to be replaced.

The explanation is that when the engine is cold and also in higher RPMs there is high fuel consumption and there is no excess fuel but in lower RPMs the excess fuel can't pass through the valve and the engine is running on really rich mixture.

I hope this helps somebody else out. It took us 3 weeks to find the problem.

Cheers!

Apr 23rd, 2022, 16:00	#1
darlik New Member Last Online: Apr 29th, 2022 18:22 Join Date: Apr 2022 Location: Varna	Rough acceleration when engine is warm Hello guys, I'm new to this forum and I need your help. I have a 2008 Volvo V50 2.0d 136hp. The car has a problem during acceleration between 1500 - 2100 RPM. The whole cars is shaking back and forth when the pedal is normally pressed. If I fully press the pedal there is no problem. The problem is only present in this RPM range and when the cooling liquid temperature is above 60 degrees. When the engine is cold there is no problem. It all started after the turbo failed. I've managed to turn off the engine by engaging 5th gear and releasing the clutch. After that the turbo was replaced and it turned out that one of the injectors was bad too. The faulty injector was replaced. After 600km this problem appeared. After that all injectors were inspected again and they are fine. There are no error codes or anything. It's not the pedal position sensor because the problem is present during cruise control acceleration too. Fuel filter is replaced too. I have no clue what to check next. I know that the fuel pressure should be different when the engine is cold and when it is warm, but I don't know the exact numbers to make a reference. I hope someone can help me. Cheers!

Apr 23rd, 2022, 21:19	#2
passenger Master Member Last Online: Apr 2nd, 2024 21:40 Join Date: Feb 2021 Location: Mountains	Wish you have some code reader. I would go for EGR valve. Try to disconnected EGR valve (just connector) and try it. Volvo VIDA would solve problem. You could see movements of EGR

Apr 23rd, 2022, 22:45	#4
passenger Master Member Last Online: Apr 2nd, 2024 21:40 Join Date: Feb 2021 Location: Mountains	Huh no idea more sorry. Quick google put me on this forum and this thread https://www.volvoforums.org.uk/showthread.php?t=297220

Apr 29th, 2022, 17:47	#5
darlik New Member Last Online: Apr 29th, 2022 18:22 Join Date: Apr 2022 Location: Varna	Hello again. We resolved the issue. There is one-way valve on the fuel return pipe and it was blocked. It is located under the y-shaped throttle body and it is part of the fuel temperature sensor assembly. The whole assembly needs to be replaced. The explanation is that when the engine is cold and also in higher RPMs there is high fuel consumption and there is no excess fuel but in lower RPMs the excess fuel can't pass through the valve and the engine is running on really rich mixture. I hope this helps somebody else out. It took us 3 weeks to find the problem. Cheers!

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