Fuel pump noise

[mt308]

Last year I had some issues with the filter being blocked with some swarf material from the tanks (they don't use this stuff any more I understand).

The car cut out a number of times when hot - once I cleared out the 100m filter it has not happened again (there was some metallic looking material in there).

However - when my tanks go below about half full I get a much higher pitched noise from the fuel pumps - why would the pitch change just due to less in the tanks?

I'm concerned this is due to more rubbish in the filter putting the system under strain again - I will clean it out when I service her next month.

Not sure if linked - but also when I stop the car after a longish run I get a lot of bubbling into the fuel surge tank for a couple of minutes. Is this normal too?

I am running standard Ultima factory set up high pressure and low pressure pump systems with a surge tank, on an LS7.

Just wondered if anyone else notices these noises changing? My concern is that it could be due to the pumps struggling due to restricted flow.

Thanks

Mark

[MarkWebb]

Increased noise usually caused by cavitation in pump. Bubbling in swirl pot may indicate hot fuel. I have given my theories many times. Some of us get it others don't. Personally going for complete fuel system simplification and redesign using modern electronics as used by all big power car manufacturers to combat these problems.

[mt308]

MarkWebb said:

Increased noise usually caused by cavitation in pump. Bubbling in swirl pot may indicate hot fuel. I have given my theories many times. Some of us get it others don't. Personally going for complete fuel system simplification and redesign using modern electronics as used by all big power car manufacturers to combat these problems.

Thanks - and I remember you being very helpful when I had my issues last year.

I have since put insulation around the swirl pot and inner sides of the tanks, they are much cooler now (the swirl pot used to be hot to touch, it isn't any more). My previous issues of cutting out were cured completely by a combination of the insulation and the cleaning of the filter (probably mainly the latter), but I have recently started to notice high pitched noises from the pump now which I think were happening around the time of the cutting out issues I had. And definitely seem to be worse with a less than full tank.

It is operating fine now from a performance aspect, so I don't plan to re-design anything at present.

That swarf material is a pain!

Cheers
Mark

[Storer]

With a full tank you will have a 'head' of fuel creating a bit of pressure. as the level drops this will diminish. I am sure you know this.

I will lay odds on the filters having some restriction in them again.

The boiling in the swirl pot probably is the vaporisation of the fuel following the drop in pressure when the pumps shut down.

The only way to know the pressure and temperature is to fit sensors (as I have).

My fuel pressure is a steady 59psi and temperature is 18 to 25 degC


Paul

[MarkWebb]

My problems were exactly as you describe. Low on fuel noisy pump engine cutting out. I solved it by creating a small amount of pressure in the swirl pot. Using a carb pressure reg set to @ 4 psi instead of an open pipe return to tanks. (any air goes through this real quick but slight pressure solves problems at input to HP pump. Check filters again to! Problem I now have is hot start almost impossible as fuel in swirl pot still boils away when standing. Do not under estimate the heat put into the fuel by the fuel pump! It is way more than gets absorbed by hot pipes! Simple test for this is to change over to full tank of fuel when the problem occurs. If problem clears then you know what is causing it!

[mt308]

OK, so dismantled entire system, no sign of anything wrong. Replaced high pressure fuel pump as that I think is the one that was cutting out. Replacement Bosch unit.

Initial restart much quiter than old one. BUT after driving for half an hour or so and getting it really hot the horrible noise has returned. Could this noise - which is a high pitched buzz (and which with my old problem used to get worse until it cut out) actually be just due to the chassis and surrounding area getting hot and vibrations changing and not something to worry about?

I was waiting for it to cut out today in a bit of light traffic but it did get me home. I then left it running for 15 minutes stationary in the garage and turned air con on full for good measure. It didn't cut out.

Maybe I am paranoid now but the noise is most definitely way louder and higher pitched when the car is fully warmed up. This high pitched noise is very similar to before....

The swirl pot and tanks were not that hot even sitting there for 15 mins on after a good run. Before it was getting quite hot. Its just the noise.

All I have not replaced now is the low pressure pump. But I am told that is not such a high pitched sound.

I am assured that my standard factory set up is used on cars that are in Dubai where they are driven in 40C heat.

I am not currently filled with confidence when planning a trip to France with my wife where it could be a lot hotter than today and where I plan to do 250 miles or so in one run. She is rapidly building a dislike to the car!

Does anyone else notice any changes in noises when their cars get warm/hot?

Mark

[Storer]

Mark

Where is your fuel pressure regulator situated?
What is the pressure when the engine is cold and when hot?
What make is it and did it come from the Factory and roughly how old is it?

You can tell from the above that I am wondering about the regulator.


Paul

[Storer]

The easiest way to tell where the noise is coming from if it still makes it when ticking over is to use a stethoscope.

A simple metal rod with a piece of wood on the end for you ear. Place on each component.

Worth a try.


Paul

[mt308]

Storer said:

Mark

Where is your fuel pressure regulator situated?
What is the pressure when the engine is cold and when hot?
What make is it and did it come from the Factory and roughly how old is it?

You can tell from the above that I am wondering about the regulator.


Paul

On the rear bulkhead up high. Factory supplied. They removed the gauge as they can leak I was told. Maybe I should put it back on and check pressures?

Car was new built by me only on the road for 2 years. 3,500 miles or so.

Its an Aeromotive.

Thanks
Mark

[mt308]

Storer said:

The easiest way to tell where the noise is coming from if it still makes it when ticking over is to use a stethoscope.

A simple metal rod with a piece of wood on the end for you ear. Place on each component.

Worth a try.


Paul

Thanks - will do that. Forecast for tomorrow is awful so might not get to it this weekend.

Mark

[Storer]

Mark

There were issues with some Aeromotive regulators that were faulty a while back.

They seem to have got over to this side of the pond!!!

The best way to tell unfortunately is replacement .


Paul

[mt308]

Storer said:

Mark

There were issues with some Aeromotive regulators that were faulty a while back.

They seem to have got over to this side of the pond!!!

The best way to tell unfortunately is replacement .


Paul

Paul

Thanks - would the noise be explained by this?

If they are faulty, if a knowen issue, I wonder if they will replace it even though out of warranty.

Mark

[Storer]

mt308 said:

Storer said:

Mark

There were issues with some Aeromotive regulators that were faulty a while back.

They seem to have got over to this side of the pond!!!

The best way to tell unfortunately is replacement .


Paul

Paul

Thanks - would the noise be explained by this?

If they are faulty, if a knowen issue, I wonder if they will replace it even though out of warranty.

Mark

Could be the cause..

There is no harm in wishful thinking but I suspect you will be paying full retail. But do check for the noises first.


Paul

[F.C.]

If you are using 044 Bosch high pressure pump then the noise is almost certainly a restriction to the pump inlet.
These pumps don't like sucking and get noisier the harder they have to suck.
One thing to check that isn't obvious is the fuel pipe from swirl pot to pump inlet I have had these collapse internally with no outward signs (on a Noble) of degradation.

[barriejames]

Hi Mark

I am close to installing fuel system and will be looking at this closely as want to avoid the same issues. I would be interested to hear when you have sorted and what the cause is? Don't worry about the other half not liking the car, mine tells me daily it's a waste on money!!!

[Storer]

The outlet from my swirl pot to the high pressure pump is -10 to help with this issue. The distance is 1.5", so nice and short.



Paul

[mt308]

F.C. said:

If you are using 044 Bosch high pressure pump then the noise is almost certainly a restriction to the pump inlet.
These pumps don't like sucking and get noisier the harder they have to suck.
One thing to check that isn't obvious is the fuel pipe from swirl pot to pump inlet I have had these collapse internally with no outward signs (on a Noble) of degradation.

Interesting - now I am running out of ideas maybe just trying new pipes is worth a go. Though I have to say more likely to be the outlet as this is where there is a bend. But you say its the inlet only that would cause the noise?
Yes its a 044 Bosch.

I wonder if heat build up causes a degredation?

Just looking at the diagram now there are 2 flexible pipes from my swirl pot to the HP pump. One goes from the bottom of the swirl pot to the 100micron filter (which I have just cleaned - interestingly when I cleaned it I thought there was some very fine black plastic apparent, degraded pipe perhaps? but nothing that would cause any material restriction) then a pipe from the filter to the HP pump (which is brand new). The old HP pump I removed had nothing in the integral gauze filter at all, but did has a small piece of metal - similar to a piece of swarf - in the mechanism, my thoughts on this were if it was overheating it could be internal damage.

Very concerned for 2 reasons - 1. My engine cost me over £20,000 and could be damaged here, 2. I have no faith I am going to make it to the end of any journey greater than about 20 miles.

Perhaps replacing both those pipes is a sensible next step. Just to confirm - are we saying the system up to the swirl pot is probably not the issue, it is the feed from swirl pot to HP pump?

Mark

Edited by mt308 on Sunday 31st May 21:48

Edited by mt308 on Sunday 31st May 22:17

[Storer]

Try the metal rod to find the source of the noise.. Works on pipes and fittings too.



Paul

[mt308]

Storer said:

Try the metal rod to find the source of the noise.. Works on pipes and fittings too.



Paul

Will do - next weekend as I need a decent drive to get noise, but not too far in case I don't make it home.

This noise has been happening ever since the car was brand new - half way back from the factory the pump got much noisier but as the car was new and I didn't know what to expect I sort of ignored it. But it didn't actually cut out until about 2,000 miles on the clock.

Thanks

Mark

[AndreasW]

mt308 said:

This noise has been happening ever since the car was brand new - half way back from the factory the pump got much noisier

My car has also a Bosch 044 installed which is quite loud since it has been new.
The pump sits inside of a surge tank (http://www.performancebyie.com/ie-submerged-044-billet-surge-tank) which is installed horizontally.
Its intake position is below the lower dash ports of the fuel tanks - so that the fuel runs into the surge tank by gravity.
Once the fuel tanks are half empty, the pump starts to be noisy.
By googling you can find a lot about noisy Bosch 044 that behave exactly the same way.
Obviously the Bosch 044 requires a certain amount of pressure on the suction side.