Fuel Gauge Errors after maintenance
Thread Starter
Newbie
Joined: Sep 2013
Posts: 5
Likes: 0
From: Rogers, Arkansas, USA
'05 E320, '09 ML320 Bluetec
Fuel Gauge Errors after maintenance
I have an '09 ML-320 Bluetec w/ about 122,000 miles on it. It has recently been hard to start, with the start sequence timing out before engine start. This was intermittent but eventually, and naturally miles away from a shop, it failed to start at all. I suspected a fuel pump issue because my cheap scanner said I only had around 70 psi fuel rail pressure during cranking and there's no way that's enough pressure to overcome the cylinder pressure at the top of the compression stroke.
Sure enough, after the wrecker got it to the shop, we discovered the in-tank fuel pump failed, the pump relay and filter also needed to be replaced and we replaced the fuel filter in the engine compartment. I got the truck home and filled it up the next morning, however the fuel gauge only indicated about 7/8 full. Two days later I filled it to the top and checked again; still 7/8 full on the gauge. I've called and made an appointment with my indie MB mechanic who said not a major issue, just keep track of my miles and continue to drive it until he could work me in.
Next day and now the gauge reads empty, regardless of the quantity in the tank. Then today the gauge started working again indicating very close to what my cheap scanner says is in the tank (60.13%).
Is there a reset ritual I can execute to resolve this problem of does it really need to go back to the shop? After all, they just replaced the in-tank pump 5 days ago.
Oh, and I have the perpetual P0101 Can't read Mass Air Flow error even though the dealer and factory worked together to solve that problem. None of the symptoms show up, but the CEL stays lit and that's the only code found.
Sure enough, after the wrecker got it to the shop, we discovered the in-tank fuel pump failed, the pump relay and filter also needed to be replaced and we replaced the fuel filter in the engine compartment. I got the truck home and filled it up the next morning, however the fuel gauge only indicated about 7/8 full. Two days later I filled it to the top and checked again; still 7/8 full on the gauge. I've called and made an appointment with my indie MB mechanic who said not a major issue, just keep track of my miles and continue to drive it until he could work me in.
Next day and now the gauge reads empty, regardless of the quantity in the tank. Then today the gauge started working again indicating very close to what my cheap scanner says is in the tank (60.13%).
Is there a reset ritual I can execute to resolve this problem of does it really need to go back to the shop? After all, they just replaced the in-tank pump 5 days ago.
Oh, and I have the perpetual P0101 Can't read Mass Air Flow error even though the dealer and factory worked together to solve that problem. None of the symptoms show up, but the CEL stays lit and that's the only code found.
MBWorld Fanatic!
Joined: Oct 2011
Posts: 7,107
Likes: 765
From: Bronx, N.Y.
2002 ML 320 & 2006 ML500
Zero, I do not own a diesel veh. but I can only supply you with info on fuel pressure which should be 116 psi. which refers to the fuel filter in the left rear.
As for the misreading of the fuel level at the Instrument Cluster, read the PDF which calls for a recoding of the I.C.
Also diesel vehicles do not have "P" codes. They have six digit code numbers. You must have a scanner which will produce the correct code numbers.
As for the misreading of the fuel level at the Instrument Cluster, read the PDF which calls for a recoding of the I.C.
Also diesel vehicles do not have "P" codes. They have six digit code numbers. You must have a scanner which will produce the correct code numbers.
Thread Starter
Newbie
Joined: Sep 2013
Posts: 5
Likes: 0
From: Rogers, Arkansas, USA
'05 E320, '09 ML320 Bluetec
Zero, I do not own a diesel veh. but I can only supply you with info on fuel pressure which should be 116 psi. which refers to the fuel filter in the left rear.
As for the misreading of the fuel level at the Instrument Cluster, read the PDF which calls for a recoding of the I.C.
Also diesel vehicles do not have "P" codes. They have six digit code numbers. You must have a scanner which will produce the correct code numbers.
https://www.amazon.com/Autel-MD802-D...ateway&sr=8-3/
As for the misreading of the fuel level at the Instrument Cluster, read the PDF which calls for a recoding of the I.C.
Also diesel vehicles do not have "P" codes. They have six digit code numbers. You must have a scanner which will produce the correct code numbers.
https://www.amazon.com/Autel-MD802-D...ateway&sr=8-3/
I was able to monitor the raw data coming off the fuel level sensors and while the data itself is suspect (13.33% full after burning 10 gallons) the gauge also fails to correlate to the input data. Another interesting point is the low-fuel-level light (LFL) doesn't necessarily come on when the gauge points to empty. On a 6 hour drive yesterday, started with full tank, the gauge read 7/8 full for about an hour, then went directly to empty but didn't illuminate the LFL for about another 30 minutes. The LFL finally came on and the input data value began increasing from 1.13% up to 60.12% which the gauge tracked nicely.
BTW, I'm not sure why MBWorld is showing me as a Newbie, my first post was back in 2013 and dealt with replacement of the in-tank fuel pump on the '05 E320s.
