Mercedes-Benz C280

1996 Mercedes-Benz C280 Fuel System   

I have 96 C 20 that has set for about a year. It would not start. I drained the fuel tank, replaced the fuel , changed the fuel filter, fule pump and the fuel pump relay. I was able to get it to run for about two hours. Then it would not restart. I refille the fuel and still no luck. I can hear the fuel pump come on sometimes and not at other times. If the fuel pump comes on it will start. I am now thinking that is some sort of sensor the triggers the fuel pump to operate. DOES THE FUEL PUMP WORK CONTINIOUS OR IS THE A SENSOR THE SENCES LOW FUEL PRESSURE AND ALLOWS IT TO WORK? iS WHERE IS THIS UNIT? DO YOU HAVE ANY OTHER IDEAS?

what engine do you have?

You need to do a fuel pressure test to see what you are getting and you may have a possible fuel pressure regulator problem.

thanks, how much pressure should I get? where is ther fuel pressure regulator? What king ogage will I need?

you can get a fuel pressure gauge at an auto parts store. the fuel pressure regulator will be at the end of one og the fuel lines a little valve looking cannister
with a vacume hose connected at the bottom or on the side of it.
There will be on the side of the fuel rail a valve stem to connect the gauge to and it should be at about 35-40 pounds of pressure .

I looked under the hood and did not find it. Went to auto parts store looking for the fuel regulator. No help, didnt carry it and no diagrams or locations info. Anda as to where this fuel regulator might be located?

it will be connected to the fuel lin right next to the intake manifold toward the front of the engine.

Does it have a hard line comming and a hard line going out? If so, I may have found it. It has the two hard lines and a rubber line on top, looks like a vacume line. Is this it?

befor you purchase the regulator you will still want to do a test of your fuel pressure at the intake manifold.
The fuel injection pressure regulator will have a gas line goig into it and the other end will be going into the intake manifold and will look like it is part of the intake
for your model I do not see it as a stand alone unit with two lines connected to it and a vacume hose,
The picture I see has a fitting for a hos plus a vacume line and a end with two-steps and two o-rings attached to it
I hope this helps

The unit I found is mounted on theright side of the engine about have way back. I took the lines loose and no fuel. the part I foungdm is mounted to the engine witha a bolt that takes a 10mm wrinch to loosen. There is only one bolt holding it in place. there is a line that is about1/2 inch id going to the unit and the same size line comming out of the unit. The outfeed line is about 10 inches long and has a 90 degree bend and I cant tell where it goes from there. Do you have access to a parts book that will give the location of this fuel regulator? The unit I found has an 1/8 inch line that I think is vacume. Could this regulator be under a cover? Every thing on this thing is very close and covered, thaks Jim

It sounds like you have the part. I have a picture that I can send you of what it looks like if you give me an email address to send it to

Thanks, its [redacted]

let me know when you recieved it

I got the photo but I can tell if its the part. What does this regulator fit into? CAN YOPU SEND ME A PARTS BOOK ILLISUSTRATION OF THE LOCATON?

The regulator fits into the intake manifold and one fuel line srecws into it while the vacume hose connects to the other side.
I cannot find any details on the location but the discription that I gave you.
They all look the same for your year car

I have looked and no joy, any Idea?

You will have to look onto the fuel rail it is posible that you are looking right at it and not recognizing it.
It is held in by a clip or snap ring, Pull straight out, push new one straight in, install retainer