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Bosch 040 into an S15

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Firstly, I (and hardtuned.net) take NO responsibility in what you do to your own or anyone else's car, you do this at your own risk, just as I did.



I recently put a bosch 040 into my S15. I was looking on the net for a guide but couldn't find one to suit because the S15 has a slightly different layout...


Things you will need:


Bosch 040 fuel pump

1 x M5 nut

1 x M6 nut

10mm socket/spanner

Ring terminals



Flat head screw driver

Needle nose pliers

Hose clamp




Now, before anything, many people recommend to disconnect the battery as a safety precaution. It is also handy to open the fuel tank lid (when you re-fuel into) to let a bit of pressure out.


First, open your boot, you can find the access point to the fuel pump here:



Take out the false floor in the boot and peel back the carpet on the little shelf. It's a lot easier if the back seats are folded forward so the carpet can be laid flat. Now you will see a grey plate with 4 screws, undo these:



When you lift up the cover (it may take a little but of pulling) there will be two plugs which you have to undo so it can be tucked out of the way. Now you will see 3 hoses, undo these one by one. I started at the hose closest to the rear of the car and worked my way forwards, and I didn't seem to lose much fuel, although I doubt it would make much of a difference. Once they are off you now need to undo the black ring, it screws off but is pretty stubborn, so get your mellet and screw driver and show it some love:



Now you can lift off the white lid. There are 2 more connectors to undo, I decided to peg these to one of the black hoses so they wouldn't fall into the fuel and so I could easily access them later. You may notice that the cradle isn't attached to the lid like on other S chassis cars, you now have to reach inside the fuel tank and pull the cradle off a slide. it comes out really easily. Now you should have this:



You will need to remove the standard (tiny) S15 pump from the bracket and fix the 040 into place. Before you do this however, you will need to measure where the existing pickup point is so you can keep that same point with the new, larger pump.



I measured from the first kink in the cradle and it was approximately 24cm. This means that you will need to cut off some of the pipe so the new pump will sit at the right height. There are two bumps at the end of the pipe, I cut to the underside of the second one which took about an inch off. Now you need to either cut off the 90° bend at the bottom of the cradle or bend it out of the way, I chose to bend. Now put your hoses on and hose clamp that mofo to the cradle.



Now you need to do the wiring. On the standard connector with the two red wires, it will tell you which wire is positive and which is negative, so no multi-meters etc are required. Simply cut off the loom, put the ring terminals on the end and connect the positive to the red, and the negative to the blue on the pump.



Now slip the cradle back in the tank on to it's slide (easier than you think). Don't forget any plugs/looms that need to be connected. Put the lid on, do up the black ring (POS!!), hook up the top hoses, the other plugs/looms and get a fire extinguisher ready. prime the fuel pump a few times to make sure there is fuel in the system ready to go (and listen to the new bee's in your tank), then start the car. Let it idle for a bit, make sure it's not doing anything silly, take it for a short drive and do the same thing.


Have fun with your new pump!

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I'll add this is pretty much the same for a Walbro 255L/hour pump.


Main differences i've noticed are;

- The wiring from standard to the walbro is exactly the same, plugs straight in.

- And you don't need to cut or clamp it to the cradle. You get an extra rubber bottom piece that will need trimming, but the pump will fit after you chop the metal feed pipe.


Was going to do my own write up but i found this and one on boostcruising


Boostcruising - Walbro 255L/h Fuel Pump Upgrade



Hope this helps.


EDIT: I should add, the little T looking white plastic piece at the very top of the rubber line, is a restrictor. Best to axe it ASAP if you want to use the pump to its full potential. Pic 4 just underneath the white lid.

Edited by 67RCE

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I just installed the Walbro Pump today as well in my S15.


I bought the GSS341, which is the incorrect one for a direct nice fit.


The problem was that the inlet and outlet on the GSS341 was opposite to each other.

If you buy the GSS342, the intlet and outlet are on the same side which makes it easier to fit onto the craddle with the rubber mount.


Also i found it harder to put back on the black cap then taking it off. I suggest you place a little lubricant such as WD40 around the edge and slowly twist it in.

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I'd also like to add guys to be careful with the orientation of the top plate when you put it back in. There are mating marks with a white mark on the car and an arrow on the top plate. I actually put mine back in within range but the right angle connectors put twisting pressure on the top plate nipples and I had a hairline crack in one of them casuing fuel to piss out everywhere.


The tip is to hook up the connectors and make sure there is not too much pressure yanking sideways at those nipples, screw the top plate into a positionso there is no pressure yanking on them. Just some food for thought! It cost me $100 and a lot of misery to solve this problem! Not to metion the stink of fuel leaking everywhere.



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Do you know if the installation is similar between an S14 and an S15?

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