I need a new fuel pump

[Baxterdown]

My 72 280SE 4.5's fuel pump is leaking. Do I really need to spend $325 on an OEM pump or is there an aftermarket alternative?

Jose

[twinockchef]

There is always a risk with the low quality after market products.

[97 SL320]

Does this have a carburetor ( mechanical or electric pump? ) or fuel injection ( electric only ) ?

There are many quality aftermarket "universal" electric fuel pumps on the market. Walbro , Airtex , Carter make inline pumps that look like a fuel filter with wires. These are solenoid pumps that pulse in operation so insulate them well to reduce noise.

There are quiet motorized pumps that look like 3 D cell batteries in a stack that might do you better. This type is a must with high pressure FI.

[Graham]

Originally Posted by Baxterdown

My 72 280SE 4.5's fuel pump is leaking. Do I really need to spend $325 on an OEM pump or is there an aftermarket alternative?

Jose

That would be a D-Jet. And it should have a D-Jet pump. It is a lower pressure pump than the later K-Jets and it has an internal relief valve to protect the injector hose connection in case of blockage in the return line.

I would be surprised if you could buy an OEM pump for $325. The original pump is no longer available, but Bosch do have a replacement Part 0580464999.

You can also use a pump for a Datsun or Nissan 280ZX (1975-1978) Nissan part number is 17011-P7211. Often available on eBay 280z Fuel Pump Genuine Nissan 1975 1978 | eBay

I would avoid aftermarket pumps like Airtex & some others that claim their pumps are suitable, but they more than likely don't have the internal relief and pressure/flow characteristics could be wrong.

[Baxterdown]

Hi Graham,

Mine is fuel injected. I'm getting the Bosh pump from MBCC -- MB Part #001 091 71 01. Retail is $390. My MBCA member price is $312 to be exact.

j.

[fasterlaster]

Originally Posted by Baxterdown

Hi Graham,

Mine is fuel injected. I'm getting the Bosh pump from MBCC -- MB Part #001 091 71 01. Retail is $390. My MBCA member price is $312 to be exact.

j.

I had to deal with this to get mine on the road. It can be made to work, but is not a direct replacement. My '73 had one of the pumps you are ordering installed, but it seemed to have seized after sitting for a long time, so we worked to replace it. I ended up getting one pump working by combining 2 different pumps.

The two issues I observed were:

1. The pump is physically smaller and does not snugly fit in the frame.
2. The electrical connector placement cause the wires to stretch more than I liked to see. (no slack)

[fasterlaster]

Oh, and FWIW our host has the Bosch version for less
1973 Mercedes-Benz 280SE 4.5 Sedan - Fuel System - Page 2

[Baxterdown]

The whole thing sounds really complicated. I thought there might just be an aftermarket alternative.

I don't like to modify my car. So, Bosch it is!

Thanks for the replies guys!!!

[Graham]

Originally Posted by Baxterdown

Hi Graham,

Mine is fuel injected. I'm getting the Bosh pump from MBCC -- MB Part #001 091 71 01. Retail is $390. My MBCA member price is $312 to be exact.

j.

It is fuel injected, but it has electronic fuel injection (Bosch Djetronic). Later Mercedes with same engine have K-jetronic mechanical fuel injection and use a different higher pressure fuel pump.

This site is from Germany and as you can see offers the part number I mentioned (BOSCH 0580464999)as a replacement for Mercedes part A0010917101. (That German PartsSPOB site is, I believe, a Bosch site)

Provided you buy from the Classic Center and give them your VIN number and they send you a pump with part number A0010917101, you should be good to go. The pump you get might look a little different than the old one - the originals are no longer available) $312 is a good price if it is for a Djet pump.

Just be careful, because some other vendors will send you a Kjet pump which is not the pump you need.

[97 SL320]

Define "modify the car" . Given the approved replacement pump apparently doesn't fit one to one some mods will have to be made. With the universal pumps a bracket can be made, hoses rerouted , sub harness made so it plugs into the stock wiring harness.

However, if you are uncomfortable specing a replacement, get the MB replacement.

I've built enough stuff from scratch so this kind of work is no big deal. And $312 Vs $70 is a big factor in my decision. If a one to one replacement was $ 125 I'd be getting the one to one to eliminate fab costs.

Here are couple of choices. I don't recall for sure D jet operational PSI but I'm thinking 15 PSI ?

See attached pic.

AIRTEX E8094 Electric Pump & Strainer Set; Rollervane; 12 volts; 12-17 PSI; 45-50 GHP; 5/16 hose; GM TBI $69.79


Higher pressure, looks the same.

AIRTEX E8445 Rollervane; 12 volts; 45-65 PSI; 35 GHP; 5/16 hose; Universal Fuel Injection $63.79

[Graham]

Originally Posted by 97 SL320

I don't recall for sure D jet operational PSI but I'm thinking 15 PSI ?

Djet: 2L/min at 30 psig and 12V. Controlled by the fuel pressure regulator.

OP should get a proper D-Jet pump with relief valve built in and flow and pressure characteristics as per Bosch original design. $316 is not much considering original Bosch pump on my '72 car still works fine after 44 years!

The new replacement pump should fit right in with little or no modification needed. It will just "look" a little different.

By the way Baxterdown, what is wrong with your existing pump?

[Idle]

Back in the 80's I needed a new fuel pump for some weird German car. It was not one I had for long.

I knew I was putting in a pump that put up a higher pressure than the old one, but that's what relief valves are for. Right?

So everything was great until the original fuel lines started cracking and spraying fuel all over the engine.

No fire, but all the hoses needed to be replaced.

[Graham]

Originally Posted by Idle

No fire, but all the hoses needed to be replaced.

There were fires in the early days of Djets due to leaky injectors as well as fuel and injector hoses and connections. I once found a burn hole in the fuel cross-over at front of engine where an ignition wire had been arcing to the fuel line. I am sure I dodged a bullet in finding that just in time. Presume there must have been something conductive in the rubber fuel lines.

[97 SL320]

I'm applying sound engineering principles not randomly picking parts out of a catalog. If the OP feels more comfortable with the MB approved but still not the same as OE pump at $ 312 , have at it.

The D jet pump specs out at 2 Liter / Min, this is 31.7 GPH . The AIRTEX E8445 has a 45 - 65 max range and is 35 GPH flow. This looks to be a good fit.

For a fuel system that uses a relief style pressure regulator , max fuel pump pressure capability is meaningless as long as it is capable of a pressure just over what the regulator is set for. You could run a 200 PSI capable pump on a 3 PSI system and the pressure won't exceed 3 PSI. ( This is assuming that the 200 PSI pump isn't of such a grossly high volume that the relief pressure regulator can't bypass enough fuel. )

A relief style fuel system is one that a pressurized line runs to the engines fuel rail , around the injectors then ending at the relief regulator. Excess fuel is them bled off to the tank controlling pressure. ( This traditionally how FI systems are built, though there are newer returnless systems that control pressure at the in tank pump )

Now, there is a over pressure relief internal to most motorized electric fuel pumps. This is to protect the pump should the filter clog. This does not exist to control overall system pressure.

Motorized electric fuel pumps come in a few pumping element types. Roller vane , georotor , rotary screw. These three are positive displacement and require a relief style pressure regulator. A turbine style pump can be deadheaded but that would be a misapplication of the pump.

On a fuel system without a pressure regulator / relief ( as found on a carburetor car ) , system pressure is controlled by the pump it's self. This type of pump has a variable displacement element such as a diaphragm or solenoid. Here, a spring dictates fuel pressure and these can be dead headed without system pressure getting to high. Put a positive displacement pump in one of these applications and pressure will rise to whatever the internal relief is set to.

As for an aftermarket pump causing all sorts of leaking hoses, the hoses were already failing and the new pump didn't cause that.

[Graham]

Originally Posted by 97 SL320

I'm applying sound engineering principles not randomly picking parts out of a catalog.

The internal relief valve protects the entire system. Both supply and return sides. This includes possible blockages in fuel pressure regulator, damper, return line that runs under car and venturi system at bottom of tank which is prone to blockage.

Looks like the OP will do the right thing and go with a quality Bosch or OE pump.

That's it for me.