Fuel pump fault.

[Bendy toy]

The bike stuttered and stopped with an almost full fuel tank. Annoying but no worries I’ve got a fuel pump controller bypass wire.
But it still would not start. I happened to have a multimeter with me and sure enough the pump was pulling 2 amps.
I called Carole Nash breakdown then gave it one last try and it started. No breakdown no service but thanks anyway.
It stopped again about 20 miles further along and struggled to get going. Then just as suddenly it was working again.

I reconnected the pump controller and this morning it behaved perfectly.

How I hate intermittent faults.

Has anyone else had fuel pump problems like this? It’s a standard pump bought from Motorworks when the original refused to empty the tank.

Bike is 08 Adventure with 74K on the clock and a non working fuel strip.

 

[Bendy toy]

The plot thickens.
Pump replaced with a spare and run on a controller bypass lead. It still won’t ****ing start.
It tries enough to kick the starter out but won’t keep going.
I’m clutching at straws but does anyone know how to test the pressure regulator?

 

[Bendy toy]

It turned out to be a schoolboy error. The FPC had indeed failed, though to be fair intermittent faults are unusual in electronic devices. The problem was mislabelled connections on the controller bypass lead. That was spinning the pump backwards so (pretty obviously) no engine start. Swapping the leads had it running normally. The bike is now running fine on the spare FPC.

 

[Joca]

Glad you found the problem and also reported back to help others.

Sent from my Moto G (4) using Tapatalk

 

[Bendy toy]

Mine had the later model black pump controller with all design faults fixed. Oh Yes!!

Whatever model/age of Hexhead you ride, make sure you have a fuel pump bypass wire, small Torx screwdrivers and pliers with you. You need pliers to get the connector out from deep in the pump top and Torx drivers to remove the covers. Also wire the bypass lead direct to battery and store it under the tool tray.

Just DONT EVER connect it back to front. That would be silly and of course I would always check for such gormlessness.

My controller screws had been dabbed with grease to keep winter at bay but were looking quite sorry for themselves. They are now well greased again.

 

[UturnTony]

My lead is zip tied to the adjuster bar under the seat and has been there for years untouched and, may the continue.

 

[Bendy toy]

If your controller goes t*ts up try the bypass both ways around before giving up and chasing non existent problems. Of course, a really sensible rider would fit a plug & socket and have it all tested and ready to go.

 

[UturnTony]

If your controller goes t*ts up try the bypass both ways around before giving up and chasing non existent problems. Of course, a really sensible rider would fit a plug & socket and have it all tested and ready to go.

The lead I have is terminated with the correct plug so only goes one way. The other end is polarised so that can't get mixed up either.

 

[AlexG]

The lead I have is terminated with the correct plug

Where did you source the plug?

(Everything else that typically fails has done on mine, it can't be too long before I need one of these.)

 

[UturnTony]

Where did you source the plug?

(Everything else that typically fails has done on mine, it can't be too long before I need one of these.)

You know what, I was trying to remember that when I posted but for the life of me couldn't think. It's a blue plug and I seem to remember cutting it off the FPC that failed on my 2006 GS years ago. How that worked I can't now think tbh as I've had quite a few sleeps since

Edit; just found it. The FPC has a lead on it that plugs into a socket accessable when you remove it so you cut that off the old one and splice it on to your bye-pass lead and Bob's your Uncle.I should have remembered that. Old age is cruel

 

[AlexG]

The FPC has a lead on it that plugs into a socket accessable when you remove it so you cut that off the old one and splice it on to your bye-pass lead and Bob's your Uncle.

Thanks, I should have known it would not be as easy as it sounded. In summary you need* a knackered FPC to make the lead in case you get a knackered FPC

(I know the lead can be made without the plug, but there would be no humour/irony in that.)

 

[UturnTony]

Thanks, I should have known it would not be as easy as it sounded. In summary you need* a knackered FPC to make the lead in case you get a knackered FPC

(I know the lead can be made without the plug, but there would be no humour/irony in that.)

And there you have it

 

[Bendy toy]

MY FPC lead was made using a knackered (silver) FPC plug. The FPC that's failed in strange ways (intermittent fuel starvation) was black painted. The replacement is bare metal. The lead originally had a plug on the end but the socket succumbed to winter salt so it's now permanently connected to the battery and coiled up under the tool tray.

Confused? No wonder I got connected the wrong way around.

The odd thing is that even running backwards the fuel pump does develop pressure. Pulling off the self-sealing fuel pipe connector still gave the characteristic spatter of fuel so I never suspected what could be going on.