C220 CDI awful MPG. SOLVED.
Discussion
Hi chaps
Any Merc specialists here? i have a c220cdi 2004 with DPF and i am getting basically around the 25mpg mark on average. it has been on star and all sensors are working as they should the DPF is not clogged up and there is basically nothing showing that could be causing this issue. all the brakes were done at the last service. 2 injectors have been replaced by the previous owner, it drives absolutely fine, I'm totally at a loss with it now. Open to suggestions.
Any Merc specialists here? i have a c220cdi 2004 with DPF and i am getting basically around the 25mpg mark on average. it has been on star and all sensors are working as they should the DPF is not clogged up and there is basically nothing showing that could be causing this issue. all the brakes were done at the last service. 2 injectors have been replaced by the previous owner, it drives absolutely fine, I'm totally at a loss with it now. Open to suggestions.
How old is the car? Mileage? How about cleaning the EGR, it could make HUGE difference.
One other very well known issue with W211 is the thermostat.
My car started running with low MPG and I've notice that the temp never goes above 65/67C... the light bulb went on
Trip to Mercedes dealer and about £60.00 quid later I walked back home. The thermostat is very easy job to replace, it took me about 20 min from start to finish. 2 miles into the test drive temp gauge went dead on 92C and my MPG went back to normal.
The 60 quid above were for 1.5 lt original Mercedes coolant and the thermostat including housing and new temp sensor (all in one box). years ago you were able to replace just the thermostat, now is all in.
However as I've mentioned is very easy job to do, 5 bolts, two hose clamps and 2 hoses. If you need more detail info of how to let me know.
PS I see that you done STAR diagnostic, I was the same and they never noticed the temp, so look into it yourself when you driving.
One other very well known issue with W211 is the thermostat.
My car started running with low MPG and I've notice that the temp never goes above 65/67C... the light bulb went on
Trip to Mercedes dealer and about £60.00 quid later I walked back home. The thermostat is very easy job to replace, it took me about 20 min from start to finish. 2 miles into the test drive temp gauge went dead on 92C and my MPG went back to normal.
The 60 quid above were for 1.5 lt original Mercedes coolant and the thermostat including housing and new temp sensor (all in one box). years ago you were able to replace just the thermostat, now is all in.
However as I've mentioned is very easy job to do, 5 bolts, two hose clamps and 2 hoses. If you need more detail info of how to let me know.
PS I see that you done STAR diagnostic, I was the same and they never noticed the temp, so look into it yourself when you driving.
Edited by pavka007 on Saturday 27th July 16:37
Edited by pavka007 on Saturday 27th July 16:37
Yep all that has been checked, the other thing being because of the DPF there is no bloody smoke which would indicate over fueling.
also it plods on ok but i wouldnt call it rapid. i can hear the turbo spin up so i dont think the issue is there. Leaving just the injectors, But can they have such a huge effect on mpg?
also it plods on ok but i wouldnt call it rapid. i can hear the turbo spin up so i dont think the issue is there. Leaving just the injectors, But can they have such a huge effect on mpg?
DennisTheMenace said:
Leaving just the injectors, But can they have such a huge effect on mpg?
Oh boy, now you are talking big difference. When I was living in the US I was introduced to a guy from Boise in Idaho. He is perhaps one of the most knowledgeable people I ever met regarding diesel engines, diesel fuelling systems and everything associated with it.His expertise is so well known that even major tdi tuners and engine manufacturers have been known to seek his input.
Please let me assure you that this is not just a talk here
He is a very valuable user in VWTDI forum. His user name is DRIVBEWIRE.
He is running his own business and his customer list reads like the world map
Many people even here from the UK are using his services. His website is:
http://www.dbwllc.net/
Just to give you a small "inside" regarding his knowledge and expertise please have a read of some of his posting to the above mentioned forum.:
http://forums.tdiclub.com/showpost.php?p=2340534&a...
http://forums.tdiclub.com/showpost.php?p=2621267&a...
The following link was posted when he was selling (long time ago) his car, have a read, it is very interesting, the guy is meticulous......NO he is perfectionist in everything he does.
http://forums.tdiclub.com/showthread.php?t=249972
His name is Pete and his email: DBWLLC@live.com
Get in touch and he will answer every question you may have. I never knew anyone so willing to help.
The bottom line to answer your question is: YES. Spray nozzles out of calibration can rob you of 20/25% of your MPG
Edited by pavka007 on Sunday 28th July 12:10
Righto, update time....
Car is all fixed, without the help of a specialist (guessed ECU, was faulty but not the cause) MB dealer (guessed injectors.... wrong!)
The previous owner had the precat drilled through as it was blocked. Therefore the front part of the exhaust wasn't getting up to temp to carry out a regen on the DPF, so, the car was contantly trying to regen the DPF and enjoyed a tipple of diesel whilst doing so. New precat and DPF and all is well, MPG is back up to around 43mpg.
funny thing is i had a gut feeling about this when i got the car, and by taking it to an MB "specialist" and main dealer i would have expected them to have found it. but then no fault codes so "computer says no"
Car is all fixed, without the help of a specialist (guessed ECU, was faulty but not the cause) MB dealer (guessed injectors.... wrong!)
The previous owner had the precat drilled through as it was blocked. Therefore the front part of the exhaust wasn't getting up to temp to carry out a regen on the DPF, so, the car was contantly trying to regen the DPF and enjoyed a tipple of diesel whilst doing so. New precat and DPF and all is well, MPG is back up to around 43mpg.
funny thing is i had a gut feeling about this when i got the car, and by taking it to an MB "specialist" and main dealer i would have expected them to have found it. but then no fault codes so "computer says no"
DennisTheMenace said:
Righto, update time....
Car is all fixed, without the help of a specialist (guessed ECU, was faulty but not the cause) MB dealer (guessed injectors.... wrong!)
The previous owner had the precat drilled through as it was blocked. Therefore the front part of the exhaust wasn't getting up to temp to carry out a regen on the DPF, so, the car was contantly trying to regen the DPF and enjoyed a tipple of diesel whilst doing so. New precat and DPF and all is well, MPG is back up to around 43mpg.
funny thing is i had a gut feeling about this when i got the car, and by taking it to an MB "specialist" and main dealer i would have expected them to have found it. but then no fault codes so "computer says no"
Good news, then.Car is all fixed, without the help of a specialist (guessed ECU, was faulty but not the cause) MB dealer (guessed injectors.... wrong!)
The previous owner had the precat drilled through as it was blocked. Therefore the front part of the exhaust wasn't getting up to temp to carry out a regen on the DPF, so, the car was contantly trying to regen the DPF and enjoyed a tipple of diesel whilst doing so. New precat and DPF and all is well, MPG is back up to around 43mpg.
funny thing is i had a gut feeling about this when i got the car, and by taking it to an MB "specialist" and main dealer i would have expected them to have found it. but then no fault codes so "computer says no"
How was it diagnosed?
after talking with a mate and explaining it we decided to pull the exhaust off as it was smelling of fumes in the car, and none of the injectors were leaking.
so with the help of said mate we pulled the precat off and DPF to be met with a hole drilled through the pre cat! Ordered a new one and a new DPF and all is well again.
so with the help of said mate we pulled the precat off and DPF to be met with a hole drilled through the pre cat! Ordered a new one and a new DPF and all is well again.
DennisTheMenace said:
after talking with a mate and explaining it we decided to pull the exhaust off as it was smelling of fumes in the car, and none of the injectors were leaking.
so with the help of said mate we pulled the precat off and DPF to be met with a hole drilled through the pre cat! Ordered a new one and a new DPF and all is well again.
So much for specialists and dealers! Eyeball mk1 wins...so with the help of said mate we pulled the precat off and DPF to be met with a hole drilled through the pre cat! Ordered a new one and a new DPF and all is well again.
No worries, as you say it's a pain when someone has an issue and doesn't finish off the thread! i have found a few threads with similar issues and no closure to them.
Just glad it's now all sorted, because i love the car, and i still think its the best looking of the C-Classes
Needs a polish, but i think i have got this shining again!
Just glad it's now all sorted, because i love the car, and i still think its the best looking of the C-Classes
Needs a polish, but i think i have got this shining again!
eldar said:
So much for specialists and dealers! Eyeball mk1 wins...
I think it's more a case of thinking logically and not being so bloody reliant on a diagnostic machine to tell me A.what's up and B.how to fix it.
Modern mechanics have nothing on the older pre-OBD chaps.
Although modern cars are getting stupidly technical, the basic principals of how the internal combustion engine work, have stayed the same.
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