Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
You must remove the low pressure hose off of the high pressure pump on the left front of the engine. You will see a rubber hose coming from the fuel filter hosegoing to the high pressure pump, just remove this rubber hose and run it into a container. You may want to purchase some extra long hose so you can set the container on the ground. Now you must jump the fuel pump relay with a jumper wire.
I'll post instructions on how to do it in a few minutes. The relay is in the right rear panel in the cargo area. I just have to look up which fuse number it is.
I mean relay number.
Micheal, to see rubber hose coming from the fuel filter hosegoing, do I have to look from top or from under the engine?
No right on top
You took off the one piece engine cover right?
You don't have to go under the car at all for this procedure
Do you have any photos of the hose, by any chance?
I assume, it's easy to disconnect the hose from high pressure pump and no need any clamps or whatever to connect it back?
Well maybe just a few hose clamps
I'll post a pic
what's jumper wire?
Just a wire use to connect 2 terminals together
Did you fill your tank up with gasoline?
No, I need to drain it for shipping
You will notice this high pressure pump on the driver's side front of the engine
Right where the yellow arrow is pointing, there is a rubber hose that is clamped there.
Take this rubber hose off and follow it to the fuel filter about 10 inches away.
Remove this end of the hose also. Take this hose to an autoparts store and buy like 6 feet worth of hose that same size.
Connect the new 6ft rubber hose to the fuel filter and put the other end into a suitable container
when I will jump wire the relay, the fuel will start to flow from the filter housing, right? Or I have to start engine too?
No, just jump the relay. That will turn the pump on and pump it all out into the container
The engine will not start anyways since you are disconnecting the fuel line to it.
Post your vin # XXXXX I'll look up the relay location.
OK. waiting for fuse number.
fuse 57, there should be a small black relay right next to it
To make sure it is the relay, pull the relay and try and start the car. If it doesn't start, then you have found the right one. The engine should just turn over but not start
You should notice the relay has 5 pins on it
You will need to jump pins 30 and 87 with a makeshift wire
I mean make your own wire
You actually could pop the cover off of the relay and get something to pinch the 2 conacts together if you don't want to make a jumper wire
Is it all the same, including fuse number, for gasoline 2012 ML350? (I will have it in 2 weeks, and likely would have to drain it's fuel too).
Yes, same for the gasoline engine too
Except to drain that fuel system, you will need a different hose.
To connect to the fuel rail under the hood.
Michael, looks like I got the answer. I am planning to drain it on Monday. Can I hit accept after I do it?
You will need this hose. http://www.tooltopia.com/mastercool-84722.aspx
Yes, you can wait until then
you mean this hose for gasoline ML350?
The hose I just showed you screws into the fuel rail on the gasoline engine for all mercedes
There are no rubber hoses to disconnect on the gasoline engine but there is a nice test port on the fuel rail that that hose will screw onto
Use the kinked end of the hose to screw onto the fuel rail since that hose is only a one way flowing hose
If you connect it to the other end, no fuel will flow
got it. Is fuel rail located at the same place?
Its actually on the passenger side, right on top. You will have to lift up the air cleaner a little bit to see it. There is a black plastic cap covering the test port.
I'll post a picture.
Actually, sorry the gasoline port should be right on top in the center with a black plastic cap
I don't think I'll be able to locate a picture for that right now but it should be pretty obvious.
does pins 30 and 87 has this numbers on them or how I have to figure out which 2 out of 5? thanks
No the relay is marked 30,31, 87,87a
So just use pins 30 which is means battery power in mercedes-benz terms. And 87 which means switched battery power.
So you are really just jumping the normally constant battery power "circuit 30" to the fuel pump.
Do not connect it to 87a
So just talk to me Monday if you have any questions. I work at the dealer during normal business hours so I may not be able to respond immediately
I will try and look at it tomorrow
Ok, just let me know.