Following on from my on going problem, as above what would make a pump get noisy?

lack of fuel?
sucking in air?

The pump is fine when car is warming up but then all of a sudden the pump becomes LOADS more noisy than usual and it causes a fuel pressure drop.

Basically i have been ticking things off the list of potential causes and so far i have replaced the pump and fuel pressure regulator with new items and rewired the fuel circuit.

Yesterday an auto electrician came and checked over the new fuel pump wiring circuit that my mate Rob did for me. Car is running a direct feed from the battery now to a new relay switched by the inertia switch.
When car is running the battery voltage is just under 14v and when lights and heaters etc are on the voltage is 13.38 or so. The pump is pulling 9A current. are these figures acceptable?

The fuse links to battery seem to have already been replaced with a proper fused wire.

The sparky also checked the battery to alternator wire. the alternator end was a bit crap so he cut the wire back to clean stuff and soldered on a decent new connection. this upped the charging voltage at the battery by 0.5V.

He reckons that the wiring is all fine and not likely to be causing the noisy pump. BTW when the pump gets noisy the current drawn doesnt increase so it isn't that.

So what could cause a noisy pump?

Only thing left to do is remove the tank and clean it out with fresh fuel then replace the filter.

any other suggestions?

chop

 

im under the impression more noise means the pump is workin harder indicating lack of fuel or air in the system?? ( awaits being shot down for being wrong!!!)

 

grant isn't it?
i'm kind of hoping thats the case and that i might get to the bottom of this! why oh why is it only when the car has warmed up though

 

Is there a vent in a cossie tank ? is it blocked?

try running car without fuel cap on i think all tanks need to breathe?


Hope this helps

 

Greg - sounds like the pump is shagged m8 thats the only explanation - have a feel of it when it gets louder, does it feel excessively warm at all? (remember, it uses the fuel to cool it aswell as pumping it)

 

yep thats me mate

 

who is Greg? Costina?

I'm hoping its not the pump because it was brand new from someone on here that did nice price.

it would make sense though because once the car was warmed up then the pump gets hot causing the problem

oh and didnt you get my pm

chop

 

I thought you were Greg Mr Chop - must be wrong

 

I did get your PM chap - been swamped lately with work and other stuff, my apologies for note replying - for me

 

its cool mate the sparky reckons the wiring is ok anyways and i said in the PM that the end of the wire from the battery wasn't showing battery voltage but it is.

what do you think to the 13.38V charging figure? and pump drawing 9A?

i suppose a bigger/better battery could only help?

 

13.3 volts is absolutely fine with everything switched on, and 9A at the pump is pretty much normal

does the current draw increase to the pump when it makes the noises? if so, new pump time

 

i reckon the current was measured only when it was noisy so surely when its warming up it wouldn't be any higher?

 

See the advice above about tank breather.

Does the tank suck in air when you take the filler cap off at the petrol station?

The noise may start once the car has warmed up because the tank has had time to produce a vaccum in the tank which will then make the pump work harder!

 

go check it again - once on initial startup when the pump sounds healthy, and then once again when the pump sounds unhealthy - post your results, cry for a bit, and then buy another pump

 

when its making the noise take teh tank cap off and see what happens

 

yeah mate sounds possible.


Anyone know if the tank has a breather then? suppose as said above i could run the car with the cap off and see what happens.

gracie
isnt it more likely that it'd be worse when noisy? ie when we saw 9A?

 

Don't know if a Cossie tank has a breather but I'd be surprised if it doesn't. On an RST its just a rubber hose connected to the top of the tank and open at the other end, just dangles down the side of the tank somewhere...quite possible for it to get blocked.

 

it would get noisy and draw more current yep.

as said above, check the breather on the tank, it comes off the top of the tank somewhere and looks like a little plastic pipe with a funnel on the end - it will be routed round the top of the tank to the left side (near the fuel pump cradle) for the ventilation, also if its a late 4x4 with a cat, it will have a charcoal canister on the inner wing with a vapour line going to the tank, check that the solenoid here is operating for the vapour

 

i hope my petrol cap is a different key then

i've got a feeling it is but i've driven the car so little that i dont actually know

i did find out yesterday though that the boot is different from the ignition and the key in the ashtray opens that

would've been rather embarrasing to call the sparky out and then not get into the boot

 

take the fuel cap off before you start the car then

 

excellent advice cheers!

BTW im saying that my pump WAS noisy when we measured 9A. you say thats fine though? wouldnt make a difference when warming up because chance is its less?

 

the tank does have a breather it runs back into the filler neck and there is a vent to atmosphere that runs round the rim of the tank

 

9 amp is about right for the fuel pump current draw, from what i remember, it has a 15 amp fuse protecting it as standard, so no worries there.

altho my uprated wiring can handle 100 amps, and has a 30 amp fuel to protect against any misdoings

 

Once the air has gone in tank pump will not b able to suck

All tanks have a breather lets in air but not out thats why when you remove cap it makes a noise

like a non return valve if the car is rolled

The breather in a saff is in the filler neck and small tube at top of tank i think one of those anyway

 

why would you want to decrease the saftey margin of the fuse Gracie??

 

thanks for that and thanks to Andy above too! this makes good sense and i'd love it to be the solution but i wont bet on it knowing my luck

 

well i removed the fuel cap and went for a drive and its still the same

what the hell makes the pump get noisy?

 

its definately a heat thing i.e does it when warm and not a time thing i.e does it after a while.

what happens if you drive and it does it and gets warm and you turn the car off straight away and try in like 5 mins will it make the noise right away then?

 

Lack of fuel I thought.

But then I do know feck all.

HTH lol

 

still does it. when we were re-wiring etc it was a while in between starting each time and it would still do it

 

Sounds like a knackered pump then!

Is it possible some shit in the tak has been disturbed in the tank and blocked the pump inlet?

Might be worth diconnecting the pump and flushing some petrol through? See if any shit comes out?

Clutching at Straws now though

 

take the pump off and run it with a bucket of water with the inlet and outlet to the bucket and see what happens to the pump then.

 

me too

next job is remove tank and clean it and check theres no crap in it. then remove pump and filter. can test pump like you suggest andy.

grrr

 

but its process of elimination now mate.....

just do it all systematically and you wil find the cause

 

ive been slowly eliminating things from the start. i hoped a new pump, reg and wiring would surely see it sorted

 

does the pump still become noisy if the tank is almost full ?

 

well ive had it with £40 of fuel in i think it was and it was noisy aye. ive barely put any fuel in for months because the damn thing hasn't been driveable!