Do both fuel pumps have to be working to get fuel to the engine on a 2006 MBZ E-350
Thread Starter
Junior Member
Joined: Jun 2007
Posts: 68
Likes: 2
From: Midwest
2000 S430, 1992 500 SEL, Range Rover HSE, 1975 450SL, 1984 Porsche 911 Convertible, 2006 MBZ E-350
Do both fuel pumps have to be working to get fuel to the engine on a 2006 MBZ E-350
My 2006 MBZ E-350 with 133,00 miles quit running all of the sudden while driving down the road. I have replaced the crankshaft sensor, fuel pump on driver's side (the pressure pump), the relay, and fuse. And the car still doesn't start.
Turning the key to the on position, I do not hear the pump making any sound, and am going to take a multi-meter to it this morning and make sure it is getting voltage. It may be quiet enough I just can't hear it, but I put my hand on it and can't feel any vibrations or anything when the key is turned on.
I did not replace the fuel pump in the passenger side because it doesn't provide the fuel to the engine, the left side does, but I was wandering if it is designed such that both have to work or the engine won't start.
Also, I assume that just taking the gas cap off and turning the key off and on for a few times will prime the pump and get it going. The pump is totally submersed in gas, and so I would assume it should prime.
My battery did go completely dead, but I assume that jumping it from the main battery in the trunk, the auxiliary battery will get charged as well.
Any ideas?
Turning the key to the on position, I do not hear the pump making any sound, and am going to take a multi-meter to it this morning and make sure it is getting voltage. It may be quiet enough I just can't hear it, but I put my hand on it and can't feel any vibrations or anything when the key is turned on.
I did not replace the fuel pump in the passenger side because it doesn't provide the fuel to the engine, the left side does, but I was wandering if it is designed such that both have to work or the engine won't start.
Also, I assume that just taking the gas cap off and turning the key off and on for a few times will prime the pump and get it going. The pump is totally submersed in gas, and so I would assume it should prime.
My battery did go completely dead, but I assume that jumping it from the main battery in the trunk, the auxiliary battery will get charged as well.
Any ideas?
Thread Starter
Junior Member
Joined: Jun 2007
Posts: 68
Likes: 2
From: Midwest
2000 S430, 1992 500 SEL, Range Rover HSE, 1975 450SL, 1984 Porsche 911 Convertible, 2006 MBZ E-350
I am somewhat confused--in your first paragraph you provide a glowing account of the car quits running-----------then in the last paragraph you say Oh by the way my battery did go dead--are you saying that is why the car stopped running, if so did you see any indication on the dash!!
With the key in the on position do you have voltage??
With the key in the on position do you have voltage??
I jumped it because the battery has gone dead, but it wasn't the reason it quit running. The engine wasn't getting fuel. Knowing the car had 133,000 miles on it, i decided to replace the fuel pump, relay, and even crankshaft sensor. After doing all of that, it turns over fine but doesn't start. I further diagnosed it this morning. The relay is working, but no voltage is showing up at any of the pins on the plug that plugs into the fuel pump ( left side). So it is something between the relay and the pump.
Thread Starter
Junior Member
Joined: Jun 2007
Posts: 68
Likes: 2
From: Midwest
2000 S430, 1992 500 SEL, Range Rover HSE, 1975 450SL, 1984 Porsche 911 Convertible, 2006 MBZ E-350
I really appreciate your reply. MBZ says the relay in the back is the only relay for the fuel pump, but there has to be another one as you are suggesting. Do you have a diagram handy pointing to the ones you are referring to?
At present, I am going to bypass them and go directly to the voltage supply of the relay in the trunk. Doing a voltage and continuity test, the most forward pin looks to be 12 volt full time to run the relay, the middle pin looks to be ground, then the two most rear pins both switch on when the key is turned on and so I was just going to hotwire the red/yellow wire in the connector to one of them directly. Or I was just going to wire it directly to the battery and make sure I won't get a short anywhere with the wire. The pump is brand new, so I am not worried about it drawing too much current.
But if I could check the relays you are referring to, it would be golden.
Thanks again, and if you have diagram, it would be great!
At present, I am going to bypass them and go directly to the voltage supply of the relay in the trunk. Doing a voltage and continuity test, the most forward pin looks to be 12 volt full time to run the relay, the middle pin looks to be ground, then the two most rear pins both switch on when the key is turned on and so I was just going to hotwire the red/yellow wire in the connector to one of them directly. Or I was just going to wire it directly to the battery and make sure I won't get a short anywhere with the wire. The pump is brand new, so I am not worried about it drawing too much current.
But if I could check the relays you are referring to, it would be golden.
Thanks again, and if you have diagram, it would be great!
MBWorld Fanatic!
Joined: Oct 2011
Posts: 1,084
Likes: 68
From: Athens, GA USA
2011 E63, 2011 Hyundai Genesis 4.6 v8, 2013 GMC Denali XL, 1965 Ford Mustang, 2005 Merc. E500
On your other post I suggested to have the car towed and to get a STAR diagnostic at a shop so not to waste money and labor on items not needed. I think that is your best path to get it repaired and not waste time and money.
Thread Starter
Junior Member
Joined: Jun 2007
Posts: 68
Likes: 2
From: Midwest
2000 S430, 1992 500 SEL, Range Rover HSE, 1975 450SL, 1984 Porsche 911 Convertible, 2006 MBZ E-350
Thanks again for the replies. The things I am doing to this car were going to be done shortly anyway, and so I am really not out anything in already putting in a fuel pump (driver's side), relay, and crankshaft sensor. The one item remaining is the passenger side fuel pump.
Can you tell me if the passenger side fuel pump is considered the pressure/sending pump, or is it the driver's side? I thought driver's originally, but am thinking it is the passenger side now. I replaced the driver's side thinking it was the pressure pump since it connected directly to the fuel line and is the initial electrical connection. But I am now thinking it is the passenger side pump that actual creates the pressure because of the way it connects up to the driver's side.
Anyone know for sure which one it is?
Also, if anyone can tell me what pins do what on the attached document it would be great. I threw away the old pump and don't want to take this one back out to find out.
Lastly, here is a picture of my front fuse/relay assembly. If you can point me to circuits 15 and 15R it would be great!
Can you tell me if the passenger side fuel pump is considered the pressure/sending pump, or is it the driver's side? I thought driver's originally, but am thinking it is the passenger side now. I replaced the driver's side thinking it was the pressure pump since it connected directly to the fuel line and is the initial electrical connection. But I am now thinking it is the passenger side pump that actual creates the pressure because of the way it connects up to the driver's side.
Anyone know for sure which one it is?
Also, if anyone can tell me what pins do what on the attached document it would be great. I threw away the old pump and don't want to take this one back out to find out.
Lastly, here is a picture of my front fuse/relay assembly. If you can point me to circuits 15 and 15R it would be great!
