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How to hardwire a fuel pump. Evo 7 8 9

66K views 62 replies 24 participants last post by  robinjamess 
#1 ·
How to hardwire a walbro 255 fuel pump in an evo 7,8,9
It is rely quite simple when you know how. To do this i bought the neverneverman kit for 35pounds. But you can buy the parts for about 10 max from maplins etc.

The main component is the four pin relay. If you know how these work then its easy to understand what your doing. Basically, its an electric switch turned on and off by the existing low voltage from the loom. How its wired:

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Right now how i did the install, start by locating the trigger wire that goes to the pump. Take out back seat, remove plastic side sill and pull rear carpet up a lil bit behind drivers seat.

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I mounted the relay right next to here, so needs a feed from the battery. Easiest way is to go across the back seat, down the passengers side of the car, then into the engine bay where the rest of the loom goes through. Make nice and neat with cable ties etc.

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Leave plenty of wire to get to the battery in engine bay. Next get the relay. You can connect the wires to it ready with spades. The neverneverman kit comes with fancy holder and the wires with crimps on ready. But not to hard to make up youself.

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You need to connect one of the trigger sides of the relay to ground. Drill a little hole, and put a small self tapper through a hoop crimp thing, connect to relay.

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Next i secured the relay, as i already had the wires attached. I just sticky padded it in the corner our the way and put a cable tie around as a safety.

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Okay so now get the pump wire we will use as the signal. The single red one down there, and cut it leaving a few cm each side to strip and crimp onto.

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Now crimp the side with the plug on as your trigger wire to the relay. And the other side as your outlet from the relay.

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So thats that side done. All you have to do now is connect up in the engine bay. Put the wire round to the battery neatly, and connect an inline fuse holder before connecting onto the battery.

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And thats it. Check it all works and put your car back together.
 
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#13 · (Edited)
Thanks for the info in this post :) Going to come in real handy! I have an EVO 6, but it looks like I might just have a slightly different plug setup (where you splice into). Concept should be the same.

Couple of questions though:

- I understand you are hardwiring because the stock fuel pump power wire in the loom cannot supply the amps required, if that is the case, why is the 12v direct connected battery wire (via the relay switch - the beefed up wire you're adding) joining up to the factory wire? (The wire that actually plugs into the fuel pump). Isn't that the wire you're trying to bypass because it can't take the amps? *edit: Just came to me then! maybe it's just the wire plugs in the loom you're looking to bypass?

- What size fuse is required on the power wire coming off the battery?

Cheers :)
 
#14 ·
Sorry guys. .I bring up this old thread because ..I just need to diy the kit as per post because my evo 7 need to have sufficient fuel generate from walbro 255..on last quote by racingroo..I need to know whatis the aadvisable fuse amp for the power direct wire ? Now I'm using 15 ..is it ok ?
 
#16 · (Edited)
Basicly same thing, but connector behind driver seat is little different, 10pin type and pump power wire is black/blue at pin number 10 (thickest wire). Works with evo 5, but I suggest to check with multimeter and workshop manual before cutting wires ;)

And one more good diy mod for evo 4-5. Bypass fuel pump relay 2 and resistor. Theres resistor used when cruising small engine loads and fp relay 2 causes a small fp voltage cut when it changes low volts to high volts. Thought this little voltage cut bug is fixed at evo 6 and later models. If you hotwire pump anyway, connect fp relay 2 pins 2 and 5 to get constant 12v for triggering new fp relay. Again, check with multimeter and workshop manual before cutting wires. Evo 5 workshop manual page c-29
 
#22 ·
Bump for a top 'How to' :)

Just finished hardwiring my IX and I wish I'd done it ages ago because I've now bypassed the resistor which lowers the pump's voltage. :thumbdown

As a result I have said goodbye to bunny hopping at low revs and hello to improved off boost response! :smthumbup:smthumbup:smthumbup

The only thing I did differently to the OP was filing down the pump output spade (#87) on the relay so I could plug the red wire directly to it. I then made a short lead with female spade crimps either end and plugged one end into the socket and the other to the coil of the relay (#86). The only advantage is that I didn't need to cut any existing wiring. :gay:
 
#31 ·
Can you do this without any mapping? I've got a few bits to do to mine one Sunday, so was going to attack this mod lol
 
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