No power to fuel pump = no start
Thread Starter
Newbie
Joined: Feb 2023
Posts: 3
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E350, C230, E300
No power to fuel pump = no start
2006 E350
Engine cranks, will come alive on starting fluid, but no pressure in fuel rail,
replaced the fuel filter in the sender unit. But noticed no voltage going to the fuel pump (under the passenger rear seat )
i checked the fuse in the trunk (fourth from bottom) and also swapped the relay near it (bottom) but still no voltage
I bench tested the motor to verify its working.
I guess I can jump/ Hotwire the relay.
It is there a way to check the signal at the ECU to see if it’s at least putting out a signal?
or anybody have something similar?.
Engine cranks, will come alive on starting fluid, but no pressure in fuel rail,
replaced the fuel filter in the sender unit. But noticed no voltage going to the fuel pump (under the passenger rear seat )
i checked the fuse in the trunk (fourth from bottom) and also swapped the relay near it (bottom) but still no voltage
I bench tested the motor to verify its working.
I guess I can jump/ Hotwire the relay.
It is there a way to check the signal at the ECU to see if it’s at least putting out a signal?
or anybody have something similar?.
MBWorld Fanatic!
Joined: May 2021
Posts: 2,527
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From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
How did you test power at the fuel pump?
The pump is energized for a few seconds when turning the key to prime the pump,, then when cranking and the engine starts. I will use a test light at the pump. When you turn the key the light will be lit for a few seconds, then off. If there is no pressure in the rail with the key on, and the test light passed, the pump is not working.
Do NOT permanently bypass the relay/ECU. It is a safety feature in case of an accident.
The pump is energized for a few seconds when turning the key to prime the pump,, then when cranking and the engine starts. I will use a test light at the pump. When you turn the key the light will be lit for a few seconds, then off. If there is no pressure in the rail with the key on, and the test light passed, the pump is not working.
Do NOT permanently bypass the relay/ECU. It is a safety feature in case of an accident.
Thread Starter
Newbie
Joined: Feb 2023
Posts: 3
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E350, C230, E300
Thanks for the advice, I used a DVM to check for voltage to the pump, but I didn’t think to be sure it’s only in the first few seconds that it’s energized.
I’ll build a test lamp to verify the power at the pump
mahalo
I’ll build a test lamp to verify the power at the pump
mahalo
MBWorld Fanatic!
Joined: May 2021
Posts: 2,527
Likes: 2,044
From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
If you have a decent MB featured scanner you can monitor the individual floaters. I did it and one was down to 0, and the other 1/4. Using a scanner it saves you opening the tank service cover. Adding a bit of fuel, say 1 or 2 gallon, and test the car to start. If it does it may work until some fuel is consumed, and the rest is pumped to the other side and stays there
Thread Starter
Newbie
Joined: Feb 2023
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E350, C230, E300
Thanks I don’t that’s fancy of a scanner just a basic one, but I built a test lamp to test the voltage going to the pump and I verified with continuity that the fuse is good and I shorted the fuel pump relay t be sure that it was not in play, and the bulb showed no voltage was going to the fuel pump when the car was cranking
I used external power source to power the pump and then I was able to start and run the engine as normal.
anybody have a good electrical diagram for the W211?
I used external power source to power the pump and then I was able to start and run the engine as normal.
anybody have a good electrical diagram for the W211?
Newbie
Joined: Jul 2024
Posts: 6
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2006 mercedes e350
Thanks I don’t that’s fancy of a scanner just a basic one, but I built a test lamp to test the voltage going to the pump and I verified with continuity that the fuse is good and I shorted the fuel pump relay t be sure that it was not in play, and the bulb showed no voltage was going to the fuel pump when the car was cranking
I used external power source to power the pump and then I was able to start and run the engine as normal.
anybody have a good electrical diagram for the W211?
I used external power source to power the pump and then I was able to start and run the engine as normal.
anybody have a good electrical diagram for the W211?
MBWorld Fanatic!
Joined: Jan 2014
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From: Republic of Texas
'99 and '05 E55 AMG
