Fuel pump constantly running - not sure why any clues?
Discussion
Hi all
Got a problem with my thundercat - my fuel pump is constantly running, it did this before so I changed it for a different one and it fixed the problem and it went back to normal I.e. A couple of 'clicks' when you turn on the ignition and a click every now and then that you can feel with your hand on the pump. However, today it's started doing the same thing, 'clicking' constantly while the engine is running and getting quite hot. Does anyone have any ideas what might be causing it? My first thoughts are there could be air getting in somehow so it can't pressurise? Also, The carbs haven't been cleaned or balanced for a while so thought it be a problem there? It hasn't hydraulically locked with petrol which I guess it might do if it was leaking into the cylinders?
May be a silly question but How does the pump know to pump? Does it have an in built pressure sensor or does it work in another way? I guess this second pump could have failed too. Is there any way to test it?
Any clues on how to diagnose the problem would be great!
I think it's a sign that it's time for a new bike ;-)
Cheers!
Got a problem with my thundercat - my fuel pump is constantly running, it did this before so I changed it for a different one and it fixed the problem and it went back to normal I.e. A couple of 'clicks' when you turn on the ignition and a click every now and then that you can feel with your hand on the pump. However, today it's started doing the same thing, 'clicking' constantly while the engine is running and getting quite hot. Does anyone have any ideas what might be causing it? My first thoughts are there could be air getting in somehow so it can't pressurise? Also, The carbs haven't been cleaned or balanced for a while so thought it be a problem there? It hasn't hydraulically locked with petrol which I guess it might do if it was leaking into the cylinders?
May be a silly question but How does the pump know to pump? Does it have an in built pressure sensor or does it work in another way? I guess this second pump could have failed too. Is there any way to test it?
Any clues on how to diagnose the problem would be great!
I think it's a sign that it's time for a new bike ;-)
Cheers!
Check the filter.
A fuel pump should pump all the time when the engine is running, there maybe (if it's fuel injected) a pressure regulator to ensure sufficient pressure is there otherwise it is designed to pump the correct pressure for the carbs.
On my 916 the fuel pump runs for a couple of seconds when the ignition is switched on, this is to get the fuel pressurised it then stops until the engine's running. If the filter is blocked then the pump has a hard time and can overheat and even cause electrical problems.
A fuel pump should pump all the time when the engine is running, there maybe (if it's fuel injected) a pressure regulator to ensure sufficient pressure is there otherwise it is designed to pump the correct pressure for the carbs.
On my 916 the fuel pump runs for a couple of seconds when the ignition is switched on, this is to get the fuel pressurised it then stops until the engine's running. If the filter is blocked then the pump has a hard time and can overheat and even cause electrical problems.
thanks!
When you say the pump should be running constantly - I was under the impression that it only pumped once every few seconds - when it makes that single click sound, mine is going constantly 2 or 3 clicks a second while the engine is running.
Will start with the filter and checking for blockages
When you say the pump should be running constantly - I was under the impression that it only pumped once every few seconds - when it makes that single click sound, mine is going constantly 2 or 3 clicks a second while the engine is running.
Will start with the filter and checking for blockages
It'll click constantly with the engine stopped if there's an air leak and can't build any pressure up against the closed float valves too. Or if the pump itself has a split diaphragm, it'll just run constantly..
As the engine will be consuming fuel from the floats when running, you should expect it to be operating fairly constantly when the engine runs.
As the engine will be consuming fuel from the floats when running, you should expect it to be operating fairly constantly when the engine runs.
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