Unplug the connector under tank. Work out which are + - to pump(wiring diagram might help) and wire up to battery.
Hi All My fuel pump isn't priming correctly. Sometimes it does, sometimes it doesn't, sometimes it does a small prime on start up but stops too soon. There is a fault somewhere. I have already changed the relay by the battery box and nothing has changed so I suspect the pump has gone or the electrics to it are faulty. How can I test it before I stump up for a new pump?
As simply as that huh. I have a spare battery that I can use. I guess it should run continually until I disconnect the battery? Is this the only test I can do?
Have you lifted tank/seat(stuff a lump of 4x2 at the back) to check pump/fuel light plug? If it looks good, check theres power going to it with a meter or bulb with wires soldered to it. If there isn't then the problem is pre pump. If there is then feed power to the pump from battery to test pump. I did read about inner tank wiring breaking down but cant remember what model. A pump could be intermittent but never heard of it personally.
I have stripped the bike and connected a battery directly to the pump. Before I stripped the bike I turned the key and annoyingly the fuel primed fully and it bloody started. So the fault is definitely intermittent. Anyway, the pump primed fuel all over my bench when I connected it directly to an external battery. It did squeak though, is this a clue? Is the connector to the pump part of the main loom or does it plug into the main loom?
There is a filter bag inside the assembly, possibly the pump might stop if that is blocked. You will need to prize the washer/clips off to get the pump assembly apart.
Thanks. So it looks like the connector is part of the main loom and the looms was replaced around six months ago for a brand new OE item so we know that is good. Should I recheck my earths then buy a pump assembly? What else could it be?
You won't need a full assembly. If you remove the assembly from the tank, take it apart and check the filter. You can also remove the pump on its own at this point. New pumps are cheep, in fact I have one here, but it is probably fine.
Ah ok. That's good news. Is your pump brand new? If not I'll stump for a new item and eliminate that as a problem. Now... When I remove the pump is fuel gonna piss everywhere, do I need to fully empty the tank?
The filter was done during a service in June, how often does it need changing? Thinking ahead here now, if the fuel pump doesn't sort it what else could it be?
If you know the o ring size then get them from here, Polymax UK I pay about 27p each for my 748 fuel pump o rings. Steve O Rings & Rubber Seals|High Temperature O Ring Suppliers|Polymax UK
Best to empty tank! But if only a little in it you could stand it upside down on the front. Petrol will piss out of the pump [emoji74]
I have just been in the garage checking through connections. I have removed the battery box again and.disconnected each connections, cleaned, squirted a bit of WD and reconnected. Again checked the ECU earth and this time removed the ECU and checked the connections there too. I spotted an earth to the starter which I cleaned and cleaned the earth to the vertical cylinder. Are there any more earthing points? Also checked all fuses, they were all fine. The main 40 amp fuse was very slightly tarnished so cleaned that. What else should I check?
