wiring the walbro 341

[eyefi]

is it possible or a bad idea to run this pump at 9v off boost?

anyone got the good wiring diag for safe constant 12v?

thanks in advance.

[Dragonball]

Mkiv.com - 12v Mod under tech section

:thumbs:

[SimonB]

Originally posted by Paul E
Mkiv.com - 12v Mod under tech section

:thumbs:

Except that will give it a constant 12V whether or not the engine is running etc. Not a great idea imho! You need a relay triggered on the output from the fuel pump ECU. 9 or 12 V is enough to trigger the relay, which then switches the constant 12V to the fuel pump. At least I think that's how you do it!

[eyefi]

anyone got a diag of this relay install?

[dude]

You need 'SUPERMATT' !!!!!!!

Dude:flame Dev

[eyefi]

electrics piss me off, damn invisible stuff that hurts and starts fires, its not natural.

[Thorin]

Originally posted by eyefi
electrics piss me off, damn invisible stuff that hurts and starts fires, its not natural.

I agree.

Why not e-mail Pete Bett's, I thought I'd seen him post a wiring diagram for this in the past.

[Matt Harwood]

You need to get a relay from RS, Maplins, or similar, that has an operating voltage range from 5v to 15v. (Can't remember the excact spec for the one I git but it would be close to those numbers).

Wire the output wire from the fuel ECU to one of the coil wires, (pins 85 and 86), on the relay, earth on the other side. Then take the 12v supply and put that on pin 30, (or input side), and connect the pump wire to pin 87, (or output wire).

It'll click a few times on start up as the voltage is a bit erratic on cranking, but it'll stop the pump from poumping petrol all over the place if you should find yourself upside down in a ditch with ruptured fuel lines and sparks everywhere! ;)

[eyefi]

cheers matt.

im running it 9/12v at the moment and it appears to b ok. ive done this based on a chat with a guy in the states running a twin pump setup like this.

im gonna swap it to 12v when i get to map it. running very rich under boost.

[Matt Harwood]

Personally, I can't see 9v being a problem, AFAIK, the ecu switches to 12v under boost anyway....

[eyefi]

9v appears to supply enough pressure until boost.

[Steve W]

I was 'told' the Walbro does NOT like 9V when I got mine ! ?

the Toyota Jap one is more tolerant of voltage.... (they said)

and....... JUST AS MATT SAYS regarding 12v.

FatS.

[eyefi]

what's the max ampage?

[Matt Harwood]

IIRC, the problem with running the Walbro pumps at lower voltage, is that they flow less fuel than a stock pump.