Fuel Pump Relay

[yellowmelos]

what are the requirements for this to work

you have 3 wires, one is the feed to the fuel pump ( black/blue ), the other 2 are live ( one from the starter switch and engine stop switch Black ) the other from the ignition control unit (which also feeds the coils ) blue/yellow.

now does the relay work on pulses from the ICU/Coils to power the pump ?

also does the pump have a pressure switch built in aswell ??

Cheers people

[rj2para (Bisto)]

The extensive post on GvS's website may well help.

www.stoeretassen.nl/My_NTV650/Benzinepomp2/Fuel_pump_replacement.htm

All the best

Roger

[McF]

To help reduce of fuel leaks and/or fire, the fuel pump will only work when the engine is running.
The input wire from the ECU closes the relay that provides power to run the pump.

It's a good question about a pressure switch. The outlet pressure isn't high (it doesn't need to be). The main requirement for it is to pump at a given rate of volume (600cc per minute).

As it's highly unlikely the engine would consume 600cc of fuel every minute (this would drain the 19 litre tank in 32 minutes), I would expect a bypass valve to be incorporated in the pump. This would ensure that positive pressure is maintained in the supply pipe with the float bowl needle valves maintaining the correct level of fuel in the carbs

[De Graaf van Salland]

I think you should also check out this post: www.ntvhonda.proboards.com/index.cgi?board=help&action=display&thread=1284

GvS

[De Graaf van Salland]

Jul 24, 2010 14:06:17 GMT 1 McF said:

It's a good question about a pressure switch. The outlet pressure isn't high (it doesn't need to be). The main requirement for it is to pump at a given rate of volume (600cc per minute).

As it's highly unlikely the engine would consume 600cc of fuel every minute (this would drain the 19 liter tank in 32 minutes), I would expect a bypass valve to be incorporated in the pump. This would ensure that positive pressure is maintained in the supply pipe with the float bowl needle valves maintaining the correct level of fuel in the carbs

As far as I know there is no pressure switch in the pump.
The only thing the pump does is increase the pressure on the petrol feed.
The is necessary because petrol doesn't flow uphill on it's own.
The lowest parts of the fuel tank are below the carbs. So, without the fuel pump, you could only use about 2/3 of the tank (I've heard of one guy who's gone for years without a fuel pump).

The pump is a simple, spring operated, (single action) piston pump. An electric coil is used the 'prime' the spring, but the actual pumping action is performed by the spring.
This means that if the carbs don't need any fuel, the pump simply stops. The pressure is still there, but there is no flow of fuel.

GvS

[jup]

I can't add any more technical details to what's been posted.
But I can mention if anyone needs a fuel cut off relay, I have a second hand working one.
It's got a cut along one side, but it is only cosmetic and I can vouch that it works. £10 posted for anyone, which is better than £60 from Wemoto, and I was quoted £82 from my 'friendly' Honda dealer .....

[yellowmelos]

Well, managed to start the bike today.. so relay works... and it is a pulse detecting relay.

cannot belive how easy is started.

also found out that the 650 Trike has restrictors fitted in the cabs so they need to come out ASAP

[ianlomas]

Hi,
I am new to this forum, been looking for advice on fuel pump relay.

Do you still have the spare fuel pump relay for sale? Went to get my bike going after winter lay up and the relay had packed up.

Thanks
Ian