R34 Gtt Neo – Fuel Pump Direct Feed Rewire

[suwidji]

not too sure what kind of relay, but it has all the numbers lol. i asked jaycar and they gave me this particular relay. I'm assuming it's the same because same termnial numbers...

i dont know if it clicks because when i try to start my car all i hear is it trying to start up lol. Kinda too far away from the relay to hear what it's doing.

[Hanaldo]

All automotive relays have the same numbers, they are defined by the DIN standard. There should be an amperage rating stamped on it somewhere. Something like NO = 70a / NC = 60a?

Don't try to start the car. Just turn the key to the ON position. The relay click is very audible, you should easily be able to hear it.

[suwidji]

oh ok, i'll have a look when i get home tonight.

What will it mean if it does click, and vice versa?

[Hanaldo]

If it clicks then the relay is working. Which means the problem is between the relay and the pump. If it doesn't click, then the relay isn't working. So either you've wired it up wrong (which I don't believe you have) or you have a busted relay.

I have a suspicion about what might be up though. Are you doing this rewire because you have just installed a new pump?

[suwidji]

hmm alright.

yeh i did just install a walbro pump. it was working fine too, until i did this re-wire.

[suwidji]

strange turn of events, i got home and car started without a hitch.

Stunned :| but glad.

measured the voltages, reading a steady 14.0-14.1

Cheers for the help Martin

[Hanaldo]

Ha! Cars

No worries mate, glad it's working for ya! Enjoy

[Hanaldo]

I would suggest wiggling all the wires and connections around with the car running though. You may have a dodgy connection somewhere. Best to just double check before it dies on you while driving.

[suwidji]

Yeh, did that too

also gave a bit of a quick squirt around the block, and ran fine.

Only thing is that the original wiring i cut is so short that there's no slack in the wiring to relocate the relay anywhere but leaving it on the parcel shelf lol. I'm sure by soldering some new wires onto the existing you can do it, but for now it's sitting tight on the shelf lol.

just glad the car runs

[Hanaldo]

Haha Yeh I had that problem too. I extended the wires by 5cm or so and mounted the relay on the back of the seat. Saves the relay getting bashed around by bumps in the road etc.

[suwidji]

so when i woke up today,the car would struggle again, and needed to be tried about 2 times before it actually worked.

also, after leaving it parked at bondi for 2 hours, it also struggled and would not start (took me 4-5 tries until it did)

Any idea what the problem is?? whenever i try to crank it up, it also takes longer to start than it used to.. like it tries a lot longer

[Hanaldo]

It's gotta be a dodgy earth mate. Where have you earthed everything?

[suwidji]

uh ok, i'll try earth it elsewhere. There's a bolt up the top left behind the parcel shelf and behind the speaker etc.

Not really sure how to describe it, but it seemed like a good spot..

that's where the ground for the relay is.

[Hanaldo]

Is it painted? Try taking it back to bare metal with a wire brush if that's where you want it. Or use a multimeter to find a better earth.

What about the fuel pump, where have you earthed that? You said at the battery? Is your battery in the boot? What size cable are you using?

[Got a Pulsar]

Don't wanna Hijack but, just a quickie...

When Earthing the Pump, is it OK to just Splice into the Earth wire or should it be cut?

I Spliced in and the pump definately spins harder but sometimes when revs drop back to idle, it sounds like the pump slows down a bit like it is still being controlled. (Due to Battery under the Bonnet, I have only Earthed my pump, not upped the Voltage.)

[suwidji]

Is it painted? Try taking it back to bare metal with a wire brush if that's where you want it. Or use a multimeter to find a better earth.

What about the fuel pump, where have you earthed that? You said at the battery? Is your battery in the boot? What size cable are you using?

nah it's bare metal, not painted. Using a multimeter from the positive and to that ground gives me 14.1V, so im assuming it's a good ground..

My battery is under the bonnet, and using 8g cable.

BUT i think i have a breakthrough!

When i turn the ignition to ON instead of trying to start the car, I can hear the relay "turning on" i guess? Once the noises have stopped, i proceed to start the engine, and it starts up without a hitch. Is this normal :\ because I haven't heard of anyone needing to wait for the relay to start up lol.

I've tried this a few times today, and the car starts up everytime.

Also, why do i read that people can hear buzzing from their pump after this rewire? I don't hear any difference :\

[Hanaldo]

Don't wanna Hijack but, just a quickie...When Earthing the Pump, is it OK to just Splice into the Earth wire or should it be cut?I Spliced in and the pump definately spins harder but sometimes when revs drop back to idle, it sounds like the pump slows down a bit like it is still being controlled. (Due to Battery under the Bonnet, I have only Earthed my pump, not upped the Voltage.)

Use a multimeter to check.

Splicing will likely work, but better to give it a solid earth. Just run a wire to the chassis somewhere.

nah it's bare metal, not painted. Using a multimeter from the positive and to that ground gives me 14.1V, so im assuming it's a good ground..

My battery is under the bonnet, and using 8g cable.

BUT i think i have a breakthrough!

When i turn the ignition to ON instead of trying to start the car, I can hear the relay "turning on" i guess? Once the noises have stopped, i proceed to start the engine, and it starts up without a hitch. Is this normal :\ because I haven't heard of anyone needing to wait for the relay to start up lol.

I've tried this a few times today, and the car starts up everytime.

Also, why do i read that people can hear buzzing from their pump after this rewire? I don't hear any difference :\

Well what you're doing is priming the fuel pump. When you turn the engine off, the fuel all drains back into the tank. When you turn the key to ON, the fuel pump primes for 3 seconds which restores pressure. BUT, I don't think this is gonna be your issue. Personally I think you should always prime the pump before cranking, but it isn't totally necessary. Fuel pressure will build, even if you don't prime the pump.

I think you should re-earth your pump. I have never understood why people think things need to be connected to the negative terminal on the battery. The battery is earthed to the chassis, therefore the whole chassis is earthed. The shorter the earth cable, the better. Running a cable all the way back to the engine bay from the boot is just asking for trouble. Its necessary for power, it isn't for earth.

Re-earth the pump to the chassis closer to the pump and see if that helps.

[Hanaldo]

Also, the buzzing you speak of is the pump motor. Some pumps are louder than others, but you should definitely be able to hear it prime. Not sure what pump you have, some can't really be heard when the car is running (also depends how loud your exhaust is). Basically the pump spins faster with higher voltage, so the buzzing gets louder.

[suwidji]

uh alright, fair enough. I'll re-earth the pump and see if it works.

Only reason i grounded to battery is because of the tutorial lol.

My exhaust is fairly loud (blitz nur spec) so maybe that's why i can't really hear it. Maybe if i chuck the silencer in, it'd be more audible lol.

thanks!

[Got a Pulsar]

Use a multimeter to check.

Splicing will likely work, but better to give it a solid earth. Just run a wire to the chassis somewhere.

Yeah I spliced / Tee'd a wire into the Earth wire and attached it to a nearby bolt and put a nut on it, but I didn't cut the wire from the controller, I just stripped some insulation back.