2003 C220CDI - Fuel gauge reads 1/4 full, tank empty.
2003 C220CDI - Fuel gauge reads 1/4 full, tank empty.
Author
Discussion

daemon

Original Poster:

40,098 posts

226 months

Tuesday 28th December 2010
quotequote all
Just bought a Mercedes C220CDI Avantgarde. Very nice car, well pleased, everything working as expected, BUT the fuel gauge reads 1/4 full when its actually empty. Also, the trip computer reads around 100 miles still to go.

I spoke to the previous owner and he said it did that for years with him, they just didnt let it go below 1/4 full on the gauge.

I'd like to rectify it. Any ideas what it might be?

auto-mobile

6 posts

223 months

Tuesday 28th December 2010
quotequote all
sender units in the tank, there under the rear seats, chances are there telling the instrument cluster that there is 1/4 tank of fuel left, if you find it changes its mind in between switching the car on and off it will be the rear sam unit, my moneys on the sender units

Scott

ClassicMercs

1,703 posts

210 months

Tuesday 28th December 2010
quotequote all
I'm sure this same topic came up with the last qtr - but haven't searched back. Give it a look.

Deva Link

26,934 posts

274 months

Tuesday 28th December 2010
quotequote all
The tank is saddle shaped and yours has a problem with the system that balances the two sides. It takes fuel from one side and returns un-needed fuel to the other side.

daemon

Original Poster:

40,098 posts

226 months

Wednesday 29th December 2010
quotequote all
Is there any way i can test which of these problems it may be without spending any money up front?

Deva Link

26,934 posts

274 months

Wednesday 29th December 2010
quotequote all
How much fuel does it take to fill it when it reads quarter full?

There's a thread on one of the MB forums from an indie who says he's recently had a couple of high pressure pumps with sticking valves - this causes a lot of fuel to be sent back to the tank and one side to empty while the other stays quarter to half full.
He doesn't explain why the tanks don't balance though - I thought it was done by a tube at the tank, but perhaps it's more complicated than that.

daemon

Original Poster:

40,098 posts

226 months

Wednesday 29th December 2010
quotequote all
Deva Link said:
How much fuel does it take to fill it when it reads quarter full?

There's a thread on one of the MB forums from an indie who says he's recently had a couple of high pressure pumps with sticking valves - this causes a lot of fuel to be sent back to the tank and one side to empty while the other stays quarter to half full.
He doesn't explain why the tanks don't balance though - I thought it was done by a tube at the tank, but perhaps it's more complicated than that.
Will check it out next time it needs a fill - probably early next week.

Cheers

daemon

Original Poster:

40,098 posts

226 months

Tuesday 18th January 2011
quotequote all
ok, well when the car is 'empty' (ie, its reading a quarter full) then it takes just 40 litres to fill it.

This would suggest as has been said that the tank isnt draining fully.

What can i do from here? I have it going to a mechanics later this week, but he seems lost as to what to do to check it?

Deva Link

26,934 posts

274 months

Wednesday 19th January 2011
quotequote all
daemon said:
I have it going to a mechanics later this week, but he seems lost as to what to do to check it?
Try a Merc specialist - any here near you? http://www.mbclub.co.uk/forums/general-discussion/...