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Never really noticed anything - but then the engine is normally running and so it would have to be significantly loud to hear it.
I can't imagine how air would get in except on the low pressure side. Do you have plenty of fuel in the tank - that's the only place I can think that air would get into what is essentially a sealed system.
Is your engine running yet? If it is I wouldn't worry about it. It's easy to get paranoid during the build (I should know....)
You connecting rubber to copper? I found that flaring the ends of the copper - especially after the fuel pump - made things run more smoothly. The M20 however is so loud I couldn't year anything but injector noise and tappets
You connecting rubber to copper? I found that flaring the ends of the copper - especially after the fuel pump - made things run more smoothly. The M20 however is so loud I couldn't year anything but injector noise and tappets
That's interesting!
Do I take it from your comment you could hear yours and wanted to do something to reduce the noise? - and that flaring the copper pipes then made a difference . The thought never even crossed my mind.
Whilst I understand the engine noise will drown the pump noise, it is noisey when the ignition is switched to run, prior to starting my engine, and then it remains running for around 5 seconds after the engine is switched off (I guess to ensure there is always pressure in the fuel rail?)
When I first tested it there seemed to be a bit too much of a build up of pressure / noise going from rubber to copper when I stuck my ear next to it - ie hitting a flat end bit of copper then being forced through the smaller hole. The small flare smoothed it out, at least to my ear.
Can anyone hear the petrol being pumped through their fuel injection rail?
Mine is very evident, and I did not expect it. I wonder if I have a problem soemewhere?
Sytec have suggested it could be sucking in air, but I can't find it if it is?
Any ideas?
Mike
Hi Mike,
as mentioned before, I think your pump may be sucking air in from your tank.
Here's my theory....
Those Sytec fuel pumps operating at 3 bar (43psi!!) and can shift 150 litres an hour. (...so I think that makes it 5 litres in 24 seconds!)
I think your return tank connection is at a high level so maybe most of your 5 litres is being sprayed around the inside of your tank ?
Does your return connection have a pipe inside the tank that takes the returned fuel to a low level?
But on the contrary, Simon Gregory didn't seem to have a problem and appears to have the same set up as you?
That's interesting!
Whilst I understand the engine noise will drown the pump noise, it is noisey when the ignition is switched to run, prior to starting my engine, and then it remains running for around 5 seconds after the engine is switched off (I guess to ensure there is always pressure in the fuel rail?)
Mike
Mike,
With my ignition in the 'Run' position prior to start I can certainly hear the fuel pumps and if I lean over the engine I can hear the fuel moving around the fuel rail. But I wouldn't call it noisey. It's the kinda sound I would expect to hear of a fluid moving through a tube of some sort and it's certainly not loud.
What sort of noise are you getting. At the risk of getting some strange animal or other weird & wonderfull suggestions, is the noise describable........................??
If you listen to the last 3 seconds of my video with the volume turned up as loud as possible you can hear the pump continue running after the engine stops. Its nearly as noisey as the engine! I do have 3 exhausts to keep my car quiet, but see what you think.
The fuel rail noise is the sound of rushing fluid through a pipe, except I would not expect to hear a full pipe, under pressure, making noise? Sytec idea that it could be air being sucked in makes sense - but how and where? Patrick has suggested it could be the interface between rubber pipes and copper tubes causing swirling - certainly plausible. Cabrioman has suggested temporarily fitting the pum at the front end fed from a gash tank - I'll give this a go as it will eliminate all the rear filters and back to front pipework.
I'll let you know after the weekend - hopefully I will get my first drive!!!!
So much to do now! - Yeah! Its exciting times.
Mike
NigelB wrote:
Mike,
With my ignition in the 'Run' position prior to start I can certainly hear the fuel pumps and if I lean over the engine I can hear the fuel moving around the fuel rail. But I wouldn't call it noisey. It's the kinda sound I would expect to hear of a fluid moving through a tube of some sort and it's certainly not loud.
What sort of noise are you getting. At the risk of getting some strange animal or other weird & wonderfull suggestions, is the noise describable........................??
My fuel set up with low pressure pump at back and high pressure at front is up for discussion.I was using a walbro gsl391 at the front, but on a failure ,I replaced this with gsl392. I have now realized that the latter can shift 255 litres per hour as opposed to 191 litres per hour for the former,....could this be too much ..over 4 litres per minute, and paradoxically lead to fuel starvation if my fuel tank is only partly full? All advice welcome please..I know the pumps have lots of stats on the web.
Just another thought.........
have you tried running it with the petrol cap/tank vent removed?
I'm just wondering if you tank vent is working properly?
Just another thought.........
have you tried running it with the petrol cap/tank vent removed?
I'm just wondering if you tank vent is working properly?
Hi Peter
Keep the ideas coming.
On this one, I tested the pump in the engine bay as close to the fuel rail as possible, taking fuel from an open gerry can, and still get the noise. So air/starvation is not the cause. Nor is it anything in the filters and back to front supply line.
I'm left with only one idea: It's the sheer vloume and pressure of fluid being pushed around. So, short of buying a new lower spec pump, I'm just going to have to live with it.....................unless someone comes up with any other suggestion.
Or maybe.........Could I fit a fuel flow rate restrictor immediately after the pump? This might work if it is possible to find the right valve, but could I then end up with fuel starvation?
Out of interest, I removed the tank (to change a diff support bracket) and tested the pump/fuel rail in the engine bay. This also allowed me to see the flow rate back to the tank via the disconnected return/dump line. Petrol is ejected back to the tank at surprisingly high pressure, and significant volume - it did not take long to fill my 5 litre spare fuel can.
Could you not fit an adjustable regulater in the line so you can play about with the fuel rail pressures to try and find a happy compromise. FSE do a universal one but its not cheap but if it does the job...
On this one, I tested the pump in the engine bay as close to the fuel rail as possible, taking fuel from an open gerry can, and still get the noise. So air/starvation is not the cause. Nor is it anything in the filters and back to front supply line.
I'm left with only one idea: It's the sheer vloume and pressure of fluid being pushed around. So, short of buying a new lower spec pump, I'm just going to have to live with it.....................unless someone comes up with any other suggestion.
Or maybe.........Could I fit a fuel flow rate restrictor immediately after the pump? This might work if it is possible to find the right valve, but could I then end up with fuel starvation?
Out of interest, I removed the tank (to change a diff support bracket) and tested the pump/fuel rail in the engine bay. This also allowed me to see the flow rate back to the tank via the disconnected return/dump line. Petrol is ejected back to the tank at surprisingly high pressure, and significant volume - it did not take long to fill my 5 litre spare fuel can.
Thanks, Mike. So that discounts most theories !
If your input pipe was firmly under the petrol there could be no chance of any air entering the system.
Maybe a faulty pump after all?
I guess one additional side benefit of a swirl pot is any air bubbles will naturally gather at the top of the tank and then be drawn back to the petrol tank by the LP pump. The high pressure circuit is automatically purged of any air. (sorry, that's not very helpful in your case )
)