koiking125
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| posted on 14/8/10 at 11:04 AM |
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Fireblade fuel pump problem (Help)
Morning All,
Earlier in the year I was having problems with the fuel pump on my MK Blade (carbed), Fitted a brand new one and thought that was that. I was never
quite sure about the new one as it ran all the time and was quite noisey, the old one used to shut off until fuel was needed and just tick every now
and then
Gone to start it this morning and and its getting no fuel, slightly pressurised the tank to push fuel to the pump and it will then pump for a bit but
gradually grind to a halt (still running all the time and noisey).
Any help would be greatly appreciated.
Hope I dont need another new one.
Kev
MK Owners Club Member (Frosty) No.1159
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MakeEverything
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| posted on 14/8/10 at 11:37 AM |
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Sounds like the ECU??
The ECU should shut off the fuel pump when it has primed, then run it for a few seconds each revolution of the engine. Each revolution starts the
timer again. If you stall the engine, it should run on for that time and stop.
ETA: Sorry, just realised its Carbs. Not sure in that case, but i would imagine it should work in a similar way.
[Edited on 14-8-10 by MakeEverything]
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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koiking125
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| posted on 14/8/10 at 11:54 AM |
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Sorry didnt say it was a 918rrv engine, were'nt they gravity fed from the tank on the bike?? so ECU does'nt know there's a pump. Its
just there because the tanks not above the engine.
Stand to be corrected!
Kev
MK Owners Club Member (Frosty) No.1159
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MakeEverything
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| posted on 14/8/10 at 11:56 AM |
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Yes i think youre right. Do you have a return from the carbs to your tank?
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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koiking125
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| posted on 14/8/10 at 12:04 PM |
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No return from the carbs, just tank breather and outlet to pump.
Kev
MK Owners Club Member (Frosty) No.1159
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MakeEverything
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| posted on 14/8/10 at 12:12 PM |
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Sounds like the pump is pressurising the carbs and fighting against its own head pressure.
I would suggest that you need one with a pressure cut off switch, or a circulating pump with a return to the tank via a fuel pressure regulator. This
way, it will run constantly, maintain pressure to the carbs without burning out the pump.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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JF
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| posted on 14/8/10 at 12:39 PM |
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As far as I know most bike carb pumps simply use spring presure to pump. They suck in fuel from the tank with an electromagnet, but the actual pumping
towards the carbs is handled by a spring.
Nothing to do with a ecu. The pump is powered during cranking and engine running.
But most of these pumps use contact points to make and break the circuit for the electro magnet. What does your pump look like? Most have a plastic
cover at one end that can be taken off. I'd say the contacts on your new pump have got welded together... something that seems to happen to
(older) pumps. They especially hate running dry.
As you said your old pump only clicks once in a while, but when running dry it will really buzz... way to fast, so the contacts get hot and stick,
well actually spot welded.
There are some electronic after market pumps around. But they aren't 100% reliable either.
Another way that is used is to use the original (refurbed) pump. But use the contacts to switch a standard automotive relais, which switches the
magnet. The relais is more durable, and much easier to replace when broken.
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mark chandler
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| posted on 14/8/10 at 12:56 PM |
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As further above, its gravity fed from the tank so always primed.
If you have an air leak it will click all the time, also if a bit of rubbish has gone into it. On bikes they last years so no reason why a new one
would fail.
So is the pump on the floor/level with the bottom of the tank.
First thing I would do is remove and gently tap it to knock any rubbish out. Kit cars with hame made tanks tend to have little bits of swarf floating
around.
I ran my carbs for a few years on one of these
link
Regards Mark
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koiking125
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| posted on 14/8/10 at 01:18 PM |
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The pump is one of the mitsubishi units with the black plastic cap as you described. There fitted to many of the carbed bikes.
I have looked at the Facet pumps but others have put me off saying there very noisey, is this true? There obviously much cheaper.
Kev
MK Owners Club Member (Frosty) No.1159
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koiking125
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| posted on 14/8/10 at 02:37 PM |
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Thanks for all the replys.
Traced fault to dodgy cotton braided fuel hose from tank to pump. It's been drawing air through the pipe stopping the pump from being able to
pressuries. I only noticed it when I pressurised the tank a bit more to force the fuel to the pump and it was pi**ing through the side of the pipe.
New pump now works as it should and I am a happy bunny.
Who would have thought such a tiny hole could cause so much trouble.
Thanks again.
Kev
MK Owners Club Member (Frosty) No.1159
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