How To Install Walbro Gss-341 In An R34?

[Hanaldo]

Man that was quick

I don't understand that though, why would it not? Voltage drop on 2.5mm wire that is 3 maybe 4 meters long would be minimal. Resistance in series would reduce current flow, wouldn't do much to voltage. Telephone wire can flow 125v down the wire the size of a string, just low current.

I don't see how there can be anything wrong with the wiring if the pump isn't blowing fuses?

[StealthX]

Nah man maybe it refers to the pump need more voltage I.e. Stock pump - 12v, walbro - 14v.

And yeah didn't mean those thng as literal suggestions, just that 'rewire' could mean anything, need specifics. I wanna know too, I've got the same pump and have installed it with standard wiring.

[TriniGT]

What most do is use the stock wiring to power a relay and then run a direct wire from the battery to the relay and then from the relay to the pump. Idea is that once the ignition is triggered it will power the relay and from there the voltage from the direct wire from the battery is sent to the pump. You will notice the difference in the pump, it will sound angry with buzzing and the voltage which would have varied from say 11-13 volts should be somewhere from 14-15V. Remember a 255lph pump getting 11V will not push the same amount that one with 14V. On my GTT when I used the stock wiring my pressure would fluctuate due to the circuitry and my reading for my pressure was 20psi, now I get 40psi constant and my walbro makes a nice buzzing sound. Check the rating of the walbro to see as well, the recommended voltage should be 14.3V or somewhere up there.

[Hanaldo]

I don't see why it would vary so much though ^ You shouldn't see a voltage drop of more than 1v from your battery. You would never see as high as 15v unless the regulator in your alternator is stuffed. Optimal charging is between 13.8v to 14.2v, so that is the max you would see at the pump. But even so, with the stock wiring you should not lose more than 1v, if that. So you should be getting between 12.8v to 14.2v at the pump, wouldn't matter what wiring you have.

Maybe if we were talking about current it would make sense, but voltage is the same.

[TriniGT]

Have a look at this link,

http://www.skylinesaustralia.com/forums/He...mp;hl=fuel+pump

That is how I wired it up, thanks to raps86.

[TriniGT]

The GTT has a built-in voltage regulator for the pump, what happens on idle and in traffic is fluctuates the voltage. You can check for yourself if you want simple measure the voltage you get through the circuitry to the pump and measure the voltage from running a direct to it, let me know the difference, this is a known problem not something that was unique to me .

[Socrates]

From what i understand the aftermarket pump requires more voltage than the stock pump does (12v), the ecu is only sending that much voltage down to the pump.You're not getting the full performance out of your pump even though it runs the car fine now.

Edit due to replies: I have also read that the aftermarket pumps don't take the ecu voltage changes well (idle, WOT) and another reason to run a relay.

Edited September 7, 2010 by Socrates

[StealthX]

Nah man it's not varying or loosing power, the computer gives the pump variable voltage, but they need constant 12v to be tuned/used correctly...

TriniGT solved it for me, I get it now...

[Hanaldo]

The GTT has a built-in voltage regulator for the pump, what happens on idle and in traffic is fluctuates the voltage. You can check for yourself if you want simple measure the voltage you get through the circuitry to the pump and measure the voltage from running a direct to it, let me know the difference, this is a known problem not something that was unique to me .

Ahaa, that's what I was looking for. That regulator would be the reason that I couldn't find lol.

But, who says that aftermarket fuel pumps require higher voltage? I can't find anything written by Walbro stating that they need a higher voltage, you would think that if it was going to make their pumps run better then they would make sure you knew about it.

Thanks for the replies, they are answering my questions

[R31Nismoid]

Yeah, but Martin's question is, how does one re-wire the pump to provide moar power?

i.e. 'rewiring' could just mean replacing the wires that feed the current to the pump, or changing the voltage source to a constant 12v, using a voltage amplifier, adding resistors etc...

No, that is not what he asked.

I don't see why it would vary so much though ^ You shouldn't see a voltage drop of more than 1v from your battery. You would never see as high as 15v unless the regulator in your alternator is stuffed. Optimal charging is between 13.8v to 14.2v, so that is the max you would see at the pump. But even so, with the stock wiring you should not lose more than 1v, if that. So you should be getting between 12.8v to 14.2v at the pump, wouldn't matter what wiring you have.

Maybe if we were talking about current it would make sense, but voltage is the same.

Get the mutlimeter out then, and see for yourself @ idle, under load etc. It's not always enough.

1volt loss to the pump can mean quite a bit in terms of volume.

[R31Nismoid]

Ahaa, that's what I was looking for. That regulator would be the reason that I couldn't find lol.

But, who says that aftermarket fuel pumps require higher voltage? I can't find anything written by Walbro stating that they need a higher voltage, you would think that if it was going to make their pumps run better then they would make sure you knew about it.

Thanks for the replies, they are answering my questions

Check the manufactuers info.

Bosch quote thier pumps running voltage that is higher than factory.

Walbro are the same, they need more juice.

[Hanaldo]

Thanks guys, makes sense to me now

I wasn't aware of the voltage regulator, which is why I couldn't understand how there would be such a high voltage drop. Unless you had a regulator, the voltage is always going to be the same.

Will look into rewiring my pump now

[Randon_I_Am]

I'm in the same boat. I have the walbro installed at the moment with stock wiring (I've also seen my car make 266rwkw on this pump setup with 12-1 afr's)

But maybe I've one of the lucky dip good pumps that can supply that kinda fuel at ECU supplied voltage...

I've got some cable and a relay and on the cards is take the car apart and run that cable to the boot for the pump, sigh.

Does anyone know the current draw of these pumps? would hate to have a relay not capable of switching the current and fuse together, or worse blow out

[boostn0199]

This is why the nismo drop ins are the best no issues no hassles just drop it in like the stock one and your all done.

[Rolls]

This is why the nismo drop ins are the best no issues no hassles just drop it in like the stock one and your all done.

You can just drop these pumps in and you are done but they won't function optimally, the nismo one might operate at a slightly lower voltage but old dodgy wiring can still be an issue. Personally I would spend the 30 minutes running a new 12V cable from the fuse box and then power a relay via the stock wiring, gives you piece of mind and you know it will last, really isn't any work at all, a few crimp connections, pull the carpet sides up and cable tie all the cables up.

[Hanaldo]

Yeh shouldn't be much harder than wiring a sound system ^

[R31Nismoid]

Its easier.

[StealthX]

No, that is not what he asked.

Did you really need to point that out mate?

All I was saying is that Martin didn't understand the concept of 'rewiring' the stock pump, cos no one had explained that it needed DIFFERENT voltage.

It seems you just went out of your way to shut me down.

Just sayin'!

Apologies for barking up the wrong tree in advance.

[Hanaldo]

I did understand that it needed different voltage, I just didn't understand how the voltage at the pump could be less than what was at the battery because I didn't know about the regulator

[TriniGT]

If you look at the tomei pump I think they come with a relay as well and how to fit it. you probably cannot understand it but the pics should help,

http://www.tomei-p.co.jp/manuals/pdf/fuelpump_rh.pdf