Fuel system, electrical
Thread Starter
Newbie
Joined: Jun 2018
Posts: 1
Likes: 0
From: Washington State
2003 E500
Fuel system, electrical
Hello everyone,
I have an 03 E500. Yesterday I stopped at a 7-11, when I came out the car started, sputtered then died. Had it towed home and started diagnosing things. I couldn't here fuel pump so checked fuse, it was good. Then checked to see if pump had power. It did not. Then checked to see if fuel pump relay had power (from continuous power side) and it did. So I hooked up a jumper wire to bypass relay and nothing happened. Still no power at fuel pump.
Now I'm really stumped. I've been looking all over but can't find a wiring diagram. Is there anything between the relay and fuel pump wiring plug?
Thanks for the help!
Adam
I have an 03 E500. Yesterday I stopped at a 7-11, when I came out the car started, sputtered then died. Had it towed home and started diagnosing things. I couldn't here fuel pump so checked fuse, it was good. Then checked to see if pump had power. It did not. Then checked to see if fuel pump relay had power (from continuous power side) and it did. So I hooked up a jumper wire to bypass relay and nothing happened. Still no power at fuel pump.
Now I'm really stumped. I've been looking all over but can't find a wiring diagram. Is there anything between the relay and fuel pump wiring plug?
Thanks for the help!
Adam
MBWorld Fanatic!
Joined: Jan 2014
Posts: 3,969
Likes: 1,317
From: Republic of Texas
'99 and '05 E55 AMG
Just wires. Use a multimeter to confirm end-to-end continuity and then confirm the power wire is not shorted to chassis but the pump return wire is connected to chassis. FWIW, the pump only powers up for one second when the key is turned to position 1. Try hanging a fuel pressure gauge off the fuel rail to confirm pressurization or not.
The link to the following post is for an E55 (*not* your E500! very different!) but will provide you some additional info that may or may not help.
https://mbworld.org/forums/showpost....5&postcount=36
Pelican Parts has a good troubleshooting guide:
https://www.pelicanparts.com/techart...mp_Testing.htm
The link to the following post is for an E55 (*not* your E500! very different!) but will provide you some additional info that may or may not help.
https://mbworld.org/forums/showpost....5&postcount=36
Pelican Parts has a good troubleshooting guide:
https://www.pelicanparts.com/techart...mp_Testing.htm
MBWorld Fanatic!
Joined: Jan 2009
Posts: 9,225
Likes: 1,798
From: V E G A S
1922 Ford Model T / no OBD
Sounds like you are trying to repair car without scanner.
There might be lot of reason why there is no power to fuel pump. Common is bad CPS.
Without a scanner you are walking blindfolded.
There might be lot of reason why there is no power to fuel pump. Common is bad CPS.
Without a scanner you are walking blindfolded.
