Fuel Pump Replaced

If you own an e30 with an old fuel pump then I recommend replacing it even if it isn’t yet making death-rattle noises: the difference will be so obvious you’ll swear your e30 has more horsepower. This is a 20 minute job.

I got my pump and sender from the Pick n’ Pull for $70. Normally I would not have installed used parts in this application but I found a remarkable specimen and scooped it. If you have the means I suggest buying new for reliability and because there are so many after-market pumps available that are excellent and cheap especially if you have an engine with a higher than average LPH (litres per hour) requirement.


In my photo above you can see the new pump and sender have nice white plastic bits while my old parts are all brown. This isn’t aging it indicates a material update seen in newer fuel pumps. Expect to spend $250-280 for a new pump and sender, less if you retrofit a non-OEM pump.


The before (top) and after (bottom).

This job is dead simple and well documented. This thread on r3vlimited has some insights into noises and rusty fuel tanks. I won’t duplicate the step by step but I will share my notes on the procedure:

  • was happy to find foam seal still in place, though incorrectly installed
  • was not happy to find 1/8″ of dust covering everything
  • one of the nuts that hold the sender to the pump was missing: someone was in here before me apparently
  • cleaned up the dust as best i could, next time i’ll bring a brush and vacuum
  • stuffed paper towels all around the hoses
  • disconnected plugs and fuel hose (came off easily, no need to mangle the hose)
  • tried to block the hose with a sharpie but it was too big – a bic pen would work better
  • removed sender and put it in a bucket
  • could have used a hammer and screwdriver but just used muscle to spin & remove pump
  • pump locks onto the gas tank simular to the child-proof cap on medicine bottle
  • discovered the filter sock had fallen off and was in the tank
  • car has probably been guzzling all manner of dirt and gunk for years
  • based on that suspect fuel filter (1 year old) is gunked up and will need to be replaced next
  • went to home depot and bought a little claw to get the filter sock out of the tank
  • proceeded with new (to me) parts, clean up, etc.
  • car ran super rough initially probably due to air in the fuel line
  • eventually cleared up: car feels stronger, smoother acceleration
  • fuel guage still reading incorrect, may need to replace 2nd fuel level sender
  • filled up tank to try to dislodge sender float, will see how guage changes as i drive it
  • whole car reeks of gas, as do i.

Update (Monday 2012-01-28):

My e30 is messed up, stuttering and lacking power. Though it ran strong for an afternoon my “exceptional specimen” didn’t have much life left. Here’s how I’ve determined that the pump fuel supply is the problem: When the car stutters during acceleration, check the tachometer and fuel economy guages. If the RPMs drop that usually indicates a lack of spark. If the fuel economy drops that indicates the engine is starving for fuel.


My car is doing the latter, puttering at between 5 and 0 MPG in every gear and whenever the throttle is open. Tomorrow I’ll get up early and try hopefully swap in my old pump.

Update (Tuesday 2012-01-29):

The old pump improved drivability but I can tell it’s a short term fix because my old pump is making noise sometimes and the MPG frequently and nearly bottoms out just driving normally. This could be a combination of factors (fuel pump, fuel pressure regulator, injectors) but I suspect the pump.

This time it only took me 15 minutes to swap pumps but I’ll be doing it again soon so maybe I can do it even faster next time. There are several aftermarket pumps available but I decided on an OEM pump from TurnerMotorsport (they have the best price).

The bodger retrofit is to buy a pump and kit and rig it into the pump armature. The most common pump for that applicaiton is the Walbro 255 GSS-340 (DIY Retrofit Instructions). Cars with higher displacement engines or turbos sometimes put in a pump with greater LPH (litres per hour) such as the  Deatschwerks 300 LPH but that’s not necessary for a stock engine, even an s52 let alone an m20.

I’m a sucker for OEM.

Update (Sunday 2012-02-03):

I’m still convinced I have a fuel issue but my mechanic drove the car and says it has the tell-tale signs of a spark issue. I replaced the plugs in the 4 troublesome cylinders (which were actually o.k), replaced a cracked HT wire and swapped in the new distributor cap and rotor from my trunk kit for good measure: problem persists. If my mechanic is correct then the next item to inspect is the ignition coil.

Update (Tueday 2012-02-05):

My new OEM fuel pump arrived last night and I installed it in the dark. Works great and I can definitely feel that the car has new energy. Afterwards I drove it around the block with the pump exposed and the seat cushion off and it was crazy how loud the pump is. However my surging and powerloss issues prevail and I am going to replace the ignition coil to try to remedy that. As I’ve read, the coil can fail completely but it can also fail slowly causing exactly the symptoms I’m experiencing.

One last thing, It’s worth noting that every time I’ve done this there has been very little fuel in the hose coming off the pump, but this time there was much, much more fuel. It’s a good idea to remove the fuel sender before disconnecting the hose so you have somewhere to drain all that fuel.

How to:

Fuel Pump Replacement 

Part Numbers:

Suction Device with Pre-Supply Pump (255 LPH) 16141179415
O-Ring 16111744369
Sending Unit Assembly 16141152266 

Service Diagram (via RealOEM)

BMW e30: Fuel Pump Replacement

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January 26, 2013 mechanical, repairs