Stage 3 Fuel Pump from Spoolperformance DIY


May 24, 2019
2008 135i 2008 CLS63 AMG 335D
Let me start of by saying I was not sponsored by Spool but holy cow what and amazing Kit! Video at the bottom of page

I contemplated what fuel system to up grade to for 3 years before finding this one and I was completely hesitant on purchasing a bucketless set up for a daily and SCCA toy.

I went with their kit for a few reasons, life time warranty, developed and engineered by Spool, and the activation of the secondary pump got my attention.

Now this is way overkill for my set up, not even 100% FBO but, tons of room for power down the line the when I replace the fuel line the piece of mind to run E85 straight from the pump(I also have MOTIV FLEXFUEL)

Spool if you want to hook me up with a line form tank to fuel sensor, I'll gladly take one off your hands lol, but seriously.

There are so many DIY Fuel pump replacement on the E9xE8x platform I'll keep it short and post a video.

Safety glasses and gloves are highly recommended! Best to this with low amount of fuel in the tank!

-Disconnect power to the fuel pump, in my case negative battery cable
-Remove rear seat, carefully, with firm tug UP
-Remove 4 10mm bolts holding the cover to the tank, pump area
-Note the DOT on the front of the cover, this means it points forward
-Remove the two electrical connectors, squeeze and pull
-Remove the two fuel lines, squeeze and pull
-Use special tool, pump/tank ring removal tool and turn left, counter clockwise
-Now time to remove the well know PITA clip everyone has heard about
-These, should, just squeeze and pull of and almost never do, it is best to have an extra in case it breaks during removal
-The only thing you'll need from your existing set up is the float, or fuel level sensor and top hat
*Now time for assembly of the pump(s)
-Locate the correct harness for the pump to top hat to the harness going back to the body
-You will need to carefully mark and drill holes in the top hat for the power and ground of the additional pump
I- started with 9/64" drill bit and drilled my pre-marked and measured holes into the fuel hat assembly
-Use the supplied hardware with harness and carefully tighten, use your head it's only plastic and doesn't nee the strength of the HULK to ensure it's tight
-Pre-assemble the pump, harness and level to know how to locate it when placing back into the tank and take a mental note, draw a picture or what ever you need to remember the orientation and you have to assemble the two pumps while in the tank using one hand and your finger tips as a sixth sense or image there are eyeballs on your fingers, watch the video you'll see what I mean.
-Ensure all lines are secured you don't want them popping off like I did (installer issue)
-Check for binding or any areas of concern before putting the top back on and sealing it back off with the ring tool.
-Start the vehicle to make sure at least your primary pump is running and operating
*Secondary fuel pump activated VIA Spoolperformance harness and vacuum line HOBBS switch, this is a very clean and hidden set up, ties into the vacuum line coming off the brake booster to vacuum pump line(note you'll loose exhaust flapper)
-With the supplied harness, run from the pump, through the metal cover
-Run harness through, under the back seat
-Connect you fused and relayed harness to power and ground
-Connect to HOBBS switch
-Locate the brake booster hose that goes form booster to pump, you'll see a vacuum line attached
-Remove that and cap it off with supplied hardware
-The vacuum line the is going to blow off valve and to the intake manifold will be teed off with the vacuum line that goes to the exhaust flapper valve
-Open trunk, if you haven't done so already, remove the driver's side cover in the trunk, remove the pull/push clips how ever you personally know them, snake out the large and awkwardly shaped cover out of the way
-Cut and splice your HOBBS switch into that vacuum line.
*Now to test, in a controlled environment of course
-Connect your preferred devise to communicate with your preferred tuning thing and run some live data log to watch as you hit boost and and your secondary pump activate
YouTube video: