Fuel Pump Direct Feed Rewire.

[R 2 THE J]

ok i just read every post in this thread and im more confused than ever.....does someone have photos or a diagram showing what has been done.....i get that you run power cable from the +ve batt to the relay to the pump, and ground the pump to the chassis.....then how do i wire up the oem pump wiring to the relay? oem +ve to +ve on relay? then oem -ve to relay then -ve on relay to chassis or oem -ve straight to chassis.....hope this makes sense

Cheers

Yeh, I don't have a clue what's going on either.

Relay connections...HUH ???

This is a diagram I made...from what I've done so far. Any mistakes...

I really need to know what to connect on the relay and where to connect it?

[heller44]

use the original positive feed wire to the pump as the positive trigger for the relay.

a relay is composed of two parts; a coil, and a switch.

so.. you use the positive wire from the original pump installation, onto one side of the coil

then you earth the other side of the coil to chassis. so if the car says for the pump to go, the relay clicks and switches over.

then.. you attach you new big beefy power feed to one side of the switch section.

and then attach the wire from the othe side of the switch section, on a contact that is normally open circuit, to go to your pump psitive terminal.

bingo pumpo working.

therefore, your pic is ok, just needed to add the trigger wire (from original wiring) and work out which terminals are coil, and which ones are the open circuit switch.

look here --> http://www.traxide.com.au/Relay_Info.html for relay terminal piccies and descriptions..

remember, you want to use the contacts that DON'T make a circuit until the coil is activated.

hope that helps.

james.

Edited September 2, 2008 by heller44

[R 2 THE J]

use the original positive feed wire to the pump as the positive trigger for the relay.

Uhh ok..still clueless!

Maybe I should buy the relay from Jaycar first...

Are there many terminals on it or just the 3...Switch Earth and Positive

Care to elaborate A LOT LOT Deeper for a stupid guy like myself.

ie. terminals...WHAT wire goes WHERE, and in what TERMINAL!!!

I'm a 1st yr Electrician so i know basics, but not that far!!

[heller44]

look at edited post above..

If you still can't get it.. remember that places are still open in that bricklaying course.

Edited September 2, 2008 by heller44

[R 2 THE J]

Beautiful..uhh ur a farkin champion mate

yeh i know basics of relays..N/O and N/C..just didn't know what the fark was going on

A lot easier now!

Thanks

[R 2 THE J]

OK..

So this is it then in the drawing right...

So the positive that was originally goes to the pump goes into the Relay to activate the Coil and turn on.

But how does this Bypass the original Relay used as that is what i wanna do.

I want to re-wire the pump switch, where do i get that switch wire from?

This is for an R33 by the way?

Cheers

[heller44]

Simple. Don't care about modifying the previous install. Still use it to trigger the new circuit as then you will keep all the safety side of it with the ecu controlling the pump turn on and turn off. Use the lil wire that used to go to the positive on your pump to instead go to your coil on your relay.

Even if you lose a volt or two in the run of cable, the relay will still switch reliably as it only needs about 4 volts minimum to pull in.

Don't touch any more of your previous wiring other than taping up or otherwise removing the original pump negative wire. That one is no longer needed.

[R 2 THE J]

uhhh ok..so NOW..the original positive is now ONLY used as a switch..not to supply the voltage.

And the new voltage is now from the battery..gotcha...done and dusted.

thanks again!

[gumflapper]

just a question...

im gonna do this weekend. i read a few pages back someone asking the question "how is the new wiring run from the fuel pump itself to outside the tank?" how has everybody done this? i was thinking of making up a plug of sum sort and trying to use the stock connections on the cap to the fuel tank. but finding empty plugs that are compatible with those sockets are hard to come by, and by that i mean i cannot find any. so how has everybody done this?

uploaded a diagram of what i am going to do electrically but am still undecided on how to get the power into the tank for the pump

any ideas or suggestions would be appreciated

[heller44]

Are you asking about the feed to the pump itself or inside the tank for an aftermarket pump? Outside just twitch and solder and heatshrink the lot. Inside you can do the same but I am unsure that heatshrink will last immersed in fuel. I used crimps done properly.

Edited December 8, 2008 by heller44

[gumflapper]

both actually...

what i have done is wired up the "power" side of my relay unit in 6mm2 wire. im gonna mount this next to the other relays next to my battery in the boot. signal wire coming from the ECU obviously goes to the standard relay which is already next to the battery. so what im doing is taking the signal wire from that, using it to energise the coil for the fuel pump relay and using the relay to switch the fuel pump on and off like the stock wiring does... thats all sweet... what i would like to know is how ppl have run their wiring from their relays, into the fuel tank to the aftermarket pump...

pump btw is a bosch 040

[gumflapper]

anyone?

[heller44]

use the existing wiring passthrough into the tank. a little bit of thinner wire won't drop bugger all volts.

[gumflapper]

yeh i understand about voltage drop and all that stuff (im an electrician)... i was just wondering how ppl decided on how to go about it that was all...

[mtopxsecret6]

When i did my install.. i fed the larger positive wire all the way to the fuel pump itself. I also upgraded the earth wire from the pump to chassis. the only thing i had to do was increase the hole size's on the pump bracket inside the tank for the new wire to fit in. It's easy to do and should really be done i believe.

Edited December 12, 2008 by mtopxsecret6

[gumflapper]

did this 2day. also installed my bosch 040 fuel pump aswell. i can honestly say im pretty happy with the results. and i can totally understand how some ppl get confused with the wiring. easy to draw on a piece of paper, a little bit confusing curled up in the boot of ur car. what i was having trouble with was integrating my relay cct into the 33's wiring system. i took quite a few pictures of what i was doing and ill upload them tmrw arvo/nite since im @ my gf's house atm.

if you can spare a few hundred $$$ and a saturday/sunday, id reccommend doing this install. i plan later on 2 get my 33 upto around 260-270rwks and having this mod installed in my car will help with this goal.

and btw, to all those ppl out there who rekn the pump is noisy? wtf r u's all talkin about? the only time i can really hear the pump is when i turn the car over from "ACC" to "ON". the pump runs for <3 seconds and thats it (priming the fuel lines mayb). driving in traffic i cannot hear a thing and at lights with the stereo off and just the sweeeeet noise of the RB engine humming @ 750rmp idiling, i can barely hear it.

[gumflapper]

as promised a couple of fotos from the day

[mtopxsecret6]

I hope you soldered those crimps on the fuel pump, and did you run the large earth and positive wire through the original plug? so large wire's.. through original wire on plug then to large wire to pump? thats kind of only going to be as good as the original wire, it will be acting as a restrictor. Some might say it wot make much of a diference.. but.. why do the upgrade in the end if your going to retain some/part of the original wire?? It does look like a nice job, though i would modify those couple of points myself.

[daisu]

I don't see why he needs to solder the crimp connections, as long as he used quality connectors and a proper tool to crimp them.

Though you are correct in saying that the length of original wiring will act as a resistor, resistance is proportional to the length of the wire (as well as the cross sectional area), so considering the length of the original (smaller size) wiring looks like about 5cm, any difference in resistance would be negligible.

Using large diameter wiring all the way through the connector would require repinning the connector, which on some connectors can be a real PITA.

Edited December 27, 2008 by daisu

[mtopxsecret6]

go around the connector. it has a rubber boot seal.. cut a slit and go through that way.. pull the wire out and the seal reseal's itself. The crimp provides mechanical strength for the connecion.. the solder provides electrical srength for the connection, being a vibratory piece of equipment.. it could, though may not, suffer from loosness, or tearing from the vibrations etc. Crimps are only the quick and easy option anyway. My dad being an ex electrician always taught me, my work must outlive the component im workng on.

Though it does look like a good job.