Mercedes E320 Fuel Gauge Problem - PeachParts Mercedes-Benz Forum

nyko46 · #1 12-13-2019, 09:49 PM

This is what is going on with my 2008 E320 Bluetec fuel gauge:
On 12/06/19 I filled up my tank in a station where I always use.
As always the fuel gauge went to the top of fuel indicator.
My car normally drive around 620 miles with one full tank.
Driving the car normally, with less than 200 miles the gauge dropped right bellow 1/2 tank mark. I continued driving going and coming from work noticing the gauge going down faster than normally.
At around 300 miles the gauge went to "reserve light on" and after couple more miles the :message "Low Fuel" came on in the multi function display.
I then stop at the station to fill the tank again expecting an almost empty tank.
For my surprise the tank took only 10.18 gallons of fuel. Now I was expecting the gauge to go to the full tank mark but it went only to the 1/2 tank mark.
In the same day, driving the car back home the fuel gauge level went completely blank, showing no status of the fuel level.
Any idea about this symptom and why the "light indicator for low fuel level" and the "message on multi function display" came on if there was more than half tank remaining when I refill the tank?
Are there someone that had the similar problem?
What should I check first to troubleshoot this problem?
Thanks

speednjay · #2 12-14-2019, 11:29 AM

Sounds like something is wrong with the float on the sender. In not too familiar with the cdi. If the sender assembly can be reached easily I’d check that first. Possibly that the float is leaking

tjts1 · #3 12-14-2019, 11:44 AM

One of your 2 fuel level sender (it's a saddle tank) is bad. The fuel gauge combines the signal from both to work out the total fuel level. When the fuel level starts acting up you need to hook it up to a scan tool that can give you the raw signal from both fuel level senders. The system is setup to constantly move fuel from the left side to the right so it's normal to have more fuel on the passenger side.

nyko46 · #4 12-14-2019, 11:52 PM

Quote:

Originally Posted by tjts1

One of your 2 fuel level sender (it's a saddle tank) is bad. The fuel gauge combines the signal from both to work out the total fuel level. When the fuel level starts acting up you need to hook it up to a scan tool that can give you the raw signal from both fuel level senders. The system is setup to constantly move fuel from the left side to the right so it's normal to have more fuel on the passenger side.

Would a bad fuel level cause the fuel gauge at the dash board to go blank like happened with me?
I did not get any "engine light" as a warning for car malfunction. In that case connecting the scanner should show any message?
Thanks

tjts1 · #5 12-15-2019, 01:48 AM

Quote:

Originally Posted by nyko46

Would a bad fuel level cause the fuel gauge at the dash board to go blank like happened with me?
I did not get any "engine light" as a warning for car malfunction. In that case connecting the scanner should show any message?
Thanks

It could be an issue in the cluster, or rear SAM. Pull codes from each module.