Board logo

maybe daft question not efi
DRC INDY 7 - 15/11/09 at 04:58 PM

Do i need a relay from the bike to run a bike fuel pump or can i just run it from a power source with suitable fuse

[Edited on 11/15/2009 by DRC INDY 7]

coozer - 15/11/09 at 05:01 PM

I take it its efi so yes, a relay that cuts power when the engine is not running.. you don't want pressurised fuel when its off

speedyxjs - 15/11/09 at 05:01 PM

Iv fitted mine with a relay but like you, cant understand why the relay is needed.

DRC INDY 7 - 15/11/09 at 05:02 PM

it will be running zx6r carbs only on my pinto

may have posted in thr wrong forum

[Edited on 11/15/2009 by DRC INDY 7]

speedyxjs - 15/11/09 at 05:04 PM

quote:
Originally posted by coozer
I take it its efi so yes, a relay that cuts power when the engine is not running.. you don't want pressurised fuel when its off


But you wouldnt have if it is wired to ign on

coozer - 15/11/09 at 05:07 PM

Ok, carbs, no relay, thats how I had mine wired as bike pumps stop anyway if theres none being used.

Just wire it up to a switched fuse

DRC INDY 7 - 15/11/09 at 05:10 PM

cheers

robocog - 15/11/09 at 05:11 PM

Megasquirt uses a relay (it grounds it ) to control the fuel pump

If the car stalls and ingnition is left on, pump stops after a couple of seconds...

I guess its for instances of being unconcious after a crash

It is also a handy feature for being able to tweak settings that require the ECU to be on, but without the annoying drone and battery sucking pump going :-)


Regards
Rob

BenB - 15/11/09 at 05:42 PM

As above, no reed relay but a crash sensor is a good idea....

iscmatt - 15/11/09 at 08:00 PM

yup, i've no relay on mine

RichardK - 15/11/09 at 09:04 PM

I've put an inertia switch in mine to the fuel pump, just for peace of mind.

Some thing like this LINKY

Cheers

Rich

[Edited on 15/11/09 by RichardK]

BenB - 15/11/09 at 10:12 PM

That's exactly the same as mine. Good switch, works well (at least in my simulated crashes!!)...

MikeRJ - 16/11/09 at 01:01 PM

quote:
Originally posted by speedyxjs
quote:
Originally posted by coozer
I take it its efi so yes, a relay that cuts power when the engine is not running.. you don't want pressurised fuel when its off


But you wouldnt have if it is wired to ign on


You can have the ignition switched on without the engine running...

This is a safety requirement, a typical production car will have inertia sensors as well as the ECU controlling the pump. If the engine isn't running, or if there is a heavy impact the fuel pump will shut off to reduce the risk of fire.

matt_gsxr - 16/11/09 at 03:40 PM

For MS as stated it can control the fuel pump.

The other advantage of this is that when you are sitting their with the ignition (and hence MS) on whilst messing around with tables and stuff the fuel pump is not running. In my install the fuel pump runs with the ignition which flattens the battery (bike batteries are tiny).

I guess this isn't relevant, but you posted in an EFI section, so I have turned it into an EFI thread ;-)

Matt