Issue with Fuel Gauge and Sending Unit
Thread Starter
Junior Member
Joined: Oct 2013
Posts: 25
Likes: 1
From: Memphis, TN
2004 S 430
Issue with Fuel Gauge and Sending Unit
Just recently replaced the fuel pump and sending unit in my 2006 CLS 500. I was smelling gas, pulled up the rear seat and had a puddle of gas on top of the fuel sending unit. Also, the car was hard to start when cold and the fuel rail was not holding pressure any longer than a couple of hours. So I replaced both units. Car cranks right up and holds pressure now. Everything was ok, or so I thought. Problem is now the fuel gauge reads a 1/4 tank when, in fact, it is empty. Went back in to make sure everything is ok i.e. the floats are free, loose and appear to be operating as they should and all wires are connected. Not sure what to do at this point. Open for suggestions. Does the gauge have to be reset or something? Thanks for any help.
Newbie
Joined: Sep 2024
Posts: 10
Likes: 1
From: South Carolina, USA
2014 E350 Convertible
Hello TTaylor993. I'm responding to old thread you posted but I'm hoping you can help me. I have a 2008 CLK with exactly the same issues with my fuel gauge after replacing the fuel pump and sending unit.
Were you ever able to resolve your issue, and if so, how did you do it?
Were you ever able to resolve your issue, and if so, how did you do it?
Junior Member
Joined: Jun 2021
Posts: 24
Likes: 1
From: GA
CLK550; Prior CLK500
[Fuel Tank Misreading
It appears these cars have an automatic date sensor for this issue to occur. My 2007 CLK550 outta nowhere started reading four gallons less than it has in it. Strange.
QUOTE=SRRobirds;9123561]Hello TTaylor993. I'm responding to old thread you posted but I'm hoping you can help me. I have a 2008 CLK with exactly the same issues with my fuel gauge after replacing the fuel pump and sending unit.
Were you ever able to resolve your issue, and if so, how did you do it?[/QUOTE]
It appears these cars have an automatic date sensor for this issue to occur. My 2007 CLK550 outta nowhere started reading four gallons less than it has in it. Strange.
QUOTE=SRRobirds;9123561]Hello TTaylor993. I'm responding to old thread you posted but I'm hoping you can help me. I have a 2008 CLK with exactly the same issues with my fuel gauge after replacing the fuel pump and sending unit.
Were you ever able to resolve your issue, and if so, how did you do it?[/QUOTE]
Newbie
Joined: Sep 2024
Posts: 10
Likes: 1
From: South Carolina, USA
2014 E350 Convertible
Thanks for your note MrChanlyn. Were you able to solve your fuel gauge issue, and if so how did you do it?
I've got no confidence in my gauge after the car ran out of gas with the gauge showing over half full!
Thanks for any insight you can give me.
I've got no confidence in my gauge after the car ran out of gas with the gauge showing over half full!
Thanks for any insight you can give me.
Junior Member
Joined: Jun 2021
Posts: 24
Likes: 1
From: GA
CLK550; Prior CLK500
Fuel Gauge Issue - Not Resolved Yet...
I haven't addressed the issue yet. It appears to be getting worse. Meaning instead of being empty and showing a quarter tank, it's now empty and showing a half tank.
After putting approximately 3 1/2 Gs into the vehicle over the past several months, I decided to get a 2012 Infiniti G37 hard top convertible. I'll get back into that fuel gauge issue in some months, and post what my mechanic says or did. Found a good open and honest guy in the ATL after being here for a decade.
If you find out before me, please post....
QUOTE=SRRobirds;9124987]Thanks for your note MrChanlyn. Were you able to solve your fuel gauge issue, and if so how did you do it?
I've got no confidence in my gauge after the car ran out of gas with the gauge showing over half full!
Thanks for any insight you can give me.[/QUOTE]
After putting approximately 3 1/2 Gs into the vehicle over the past several months, I decided to get a 2012 Infiniti G37 hard top convertible. I'll get back into that fuel gauge issue in some months, and post what my mechanic says or did. Found a good open and honest guy in the ATL after being here for a decade.
If you find out before me, please post....
QUOTE=SRRobirds;9124987]Thanks for your note MrChanlyn. Were you able to solve your fuel gauge issue, and if so how did you do it?
I've got no confidence in my gauge after the car ran out of gas with the gauge showing over half full!
Thanks for any insight you can give me.[/QUOTE]
Newbie
Joined: Sep 2024
Posts: 10
Likes: 1
From: South Carolina, USA
2014 E350 Convertible
It turns out my issues were related to a third party fuel pump I purchased from RockAuto, supposedly built "to OEM specs". The pump was evidently sending the wrong information to the gauge. Since replacing the pump with a genuine MB pump the gauge has worked flawlessly. To RockAuto's credit, they gave me a full refund for the third party pump.
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Newbie
Joined: Sep 2024
Posts: 10
Likes: 1
From: South Carolina, USA
2014 E350 Convertible
The third party supplier was US Motor Works. In fairness, the model number identified by RockAuto was incorrect for my car. I never attempted to find the correct US Motor Works model - the issue was driving me nuts, so I just went with the MB part, even though it was about 60% more expensive.
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