2007 C220cdi low power and high fuel costs

[mjhk2001]

Hi Guys my names MJ.

I'm new to the forum.

I hope everyone is well.

I need some help with my 2007 mercedes c220 cdi w204

I bought the car from my friend who bought it for his mum new from mercedes. The car has only done 52000 miles with a full service history.

I got the car a couple of months ago for my mum and thought it would be a good purchase. And i wanted to upgrade her w203 c220cdi which was completely built proof.
So i thought its a no brainer i know the cars history and its a mercedes with low Miles.

But since ive had the car its had some issues.
Firstly the thermostat was faulty, car would not warm up etc soo i had it replaced. Thats fine but the car was always sluggish and was drinking alot of fuel. £50 i am getting less then 150 miles. Soo anyway took it for diagnostics at my local garage. It came up with fuel rail pressure regulation and fuel rail sensor high pressure. Besides that i had a code for the TCM and ESP. (i will attach the photos).
So i had fuel pressure regulator changed on the fuel rail. Cleared the codes. No codes. Awesome. NOO.

Its still driving slow and drinking loads of fuel and now i have no fault codes.

Soo i need your advise what to do next.
Your help would be much appreciated.

Thanks guys hope to hear from you soon.View attachment 92064 View attachment 92064 View attachment 92064

 

[Petrol Pete]

Hi MJ , welcome. That fuel consumption sounds terrible (better to try to put it into Mpg) but £50 of diesel should get you more than 150 miles thats about 18 Mpg ! My C55 5.4 Liter V8 does better than that around town.

Someone on here will come along soon with some answers. Be aware any un-burnt fuel could find it's way past the piston rings into the sump which will dilute the oil and destroy the engine. Check your oil level is not high. Or change the oil and check the old oil for diesel fuel. Good luck .

 

[mjhk2001]

Hi Pete thanks for the reply. Sorry Yeah the mpg is around that much which is really poor.

I did check the oil and its steady at half and seems clean. Ill try do the oil change anyway this weekend.

One mechanic said to me it could be leaking fuel injectors but i dont want to spend that money on a guess.

Yh hopefully someone can come and help me solve the problem.

Thanks for your help Pete.

Kind regards

 

[amazighman]

Does the engine run smooth or it sounds lumpy?

Did you try to clean the MAF and EGR ? Cheap starting point?

 

[Blue30]

When I had rail pressure high and low codes on mine it was the quantity control valve rather than the pressure regulator. Round on the front of the engine. The engine would often sound really harsh on throttle tip in and the performance would be really hit and miss.
If you can get a graph of rail pressure up while you’re driving it should respond instantly to throttle, not delay then spike up etc.

 

[mjhk2001]

Hi Guys, thanks for the replies.

Sorry been really busy so haven't had a chance to respond.

Amazighman:
In terms of the engine sounding smooth or lumpy its the second one. It runs rough and when im driving it seems restricted. The throttle response when driving seems hesitant but when im not in gear its fine.

I did test the MAF and it seemed okay but i will try it again. Where abouts is the EGR located? I will try to clean it.

Blue30:
Yh i did read about QCV. The fuel rail pipe coming out it has some corrosion. Which software do i need to obtain a graph of the rail pressure?

Thanks Guys.

 

[Blue30]

I used Dash Commander on my iphone, you can put graphs up of rail pressure, let me know if you manage it I can screenshot one of mine too?

 

[steve333]

Hi MJ,welcome to the forum-did the car go on star for diagnostics or a non Mercedes code reader?