300E Fuel Relay Location
 

Where is the fuel relay located in a 300E and does anyone know the part number...Would it be in the same location in a 87 and in a 90...thanks Jim

behind the battery...should be the same for both models. there are two relays in the same area...black , rectangular.... one is the a/c relay...may say "klima" on it...

Don't know if it's unique to the 400E, or just later-year W124s in general, or what, but on my car, the fuel pump relay is under the rear seat cushion on the right side.

Part number for 1987 model is 002 545 27 05 up to engine number A396764 and 003 545 24 05 for engines after that, is what I was told.

However, important to make sure you get the 6 cylinder relay, not the 4 cylinder version. I was using a pattern relay numbered 003 545 24 05 in my 300E and it wouldn't rev over 4,000 rpm. Turned out it was for a 4 cylinder engine.

The correct item should have 6zyl/6350 stamped on the side.

About the location, you'll find it behind the battery in the front on the 4 and 6 cylinder 124s. I'm guessing that the 400E and 500E relays are located in the boot next to the battery because there isn't room under the bonnet

The fuel pump relay contains the rev limiter function, so if you use a four cylinder relay in a six cylinder engine, you will only get two-thirds of design engine revolutions.

Conversely, if you use a six-cylinder relay in a four, the rev limiter will be about nine grand, but I definitely would not recommend this "mod".

Duke

Hmmm....Isn't the fuel pump relay a part of the MAS computer on the 1990 300E? And not a separate relay like on the earlier models?

Or am I experiencing confusement?

95% sure that it part of MAS Relay. Think I remember that because when I first got my '90 300E one of the lists recommended carrying a spare relay.
Couldn't find one, because it's part of the MAS relay.

Steve

fuel relay part
 

http://www.***************/catalog/lookup_parts.cfm?SubcategoryID=3380&VehicleID=1193846&Qualifier=%20&CFID=514133&CFToken=80575963

See if this link will work... it's the listing from one of the suppliers.

I carry a spare in my 1989 300e trunk. Also have an OVP spare

You are correct... the 1990 is different.

http://www.***************/catalog/lookup_parts.cfm?SubcategoryID=3380&VehicleID=1193857&Qualifier=With%204%20Pin%20Connector%20and%203 0%20Amp%20Fuse&CFID=514133&CFToken=80575963

Jim,
You evasive rascal. You are not going to tell us what year we are dealing with so I'm not going to tell you where it is, because I don't know.

Peter

1987&1990
 

Peter, I am parting out 2-300E's... a 1987 and a 1990...I have had 4 different answers so far...I have found the fuel relay in the 87.....The 90 is being evasive...Jim

not there? maybe that's why the car isn't running :)

N16/1 is the item you're looking for.

If it's a 103 engine, it's behind the battery, next to the OVP relay and adjacent to the AC relay (which is marked klima)

Yup, on my 1990 m103 (300SE) it's part of the MAS.

Confused
 

Yes, I was confused and it is next to the battery with the klima on the 87...The engine was running when I started stripping the car....thank every one for their help and ideas...I am going to close this thread....Jim

Danwatt is correct. In the 1990 model the fuel pump relay is included in the MAS unit along with the Klima relay. That is the unit by the battery that has the knob on it. Sometime in 1991 the MAS unit was eliminated and the fuel and A/C relay are incorporated into the main computer.

Peter

So they went from a free-standing relay near the battery(maybe $50), to one incorporated into the MAS($450 @ dealer), to one incorporated in a computer(sell your house-sleep in the car).

Things get old, they break and you PAYYYYYY.

Love ya MB.