CABBY FUEL PUMP making noise

Need some help guys so today I drove back from work and noticed a whining noise and a hum coming from underneath my car it sounds as though it's coming from a cylinder near back wheel next to bottom of the tank I assume that's the external fuel pump am I right any advice.

Yeah that's the fuel pump if its getting noisy it maybe on its way out or full of crud  

Ok mate thanks yes I've been doing a bit of digging through older threads just reading how I can check with disconnecting wire from pump under back seat is it right the noise maybe coming from main pump but it could be either

I'm sure they only have I pump on a mk1 externally mounted driverside rear in front of wheel
only wires going to the tank are for the gauge sender unit
put your hand on the pump and you should feel it vibrating
some are loud but if its got louder then somethings wrong
new pumps are around £80 to £120 depends where you go  

There'll be a lift pump in the tank too. 

not on mk1s upto 1983 but unsure after that??

Yes mate that's  what I mean the lift pump in tank so it could be either that or main pump under car guess I'm going to have to disconnect the wire see what happens

Sorry mate should of said I have a 1993 cabby k jet

no worries
I guess disconnect the easy one that will tell you which one making the din

Yes mate going to give it a car tomorrow I think I'll get the bosch one if it's main pump can get it from euro carpart with coupon only £107 but got a relation who works there mite be able to get cheaper fingers  crossed lol
If I'm lucky mite just be lift pump £30 job lol

the outer pump is easy to get to and you should beable to tell if its making wied noises without taking off
good luck

Cheers mate it does sound like it's the outer pump from what I'm earing outside of car thanks for your advise and help

That is the sound that the primary pump makes when the in-tank or lift pump is deceased, and that the main has to work harder to suck fuel.

I would replace the in-tank pump first, it's cheaper.
It could also be the sump/filter on the side, but usually the in-tank.

Replace the in-tank first, then add about 1pt of Marvel Mystery Oil to the gas and see if the noise abates, as it should the MMO will reduce the lacquered fuel residue on the primary pump.

Thanks Brian I'll give it ago mate

Yes I agree with Briano1234, as its happened to me a few times, main pump got very loud because the lift pump was dead/dying.
Unplug the lift pump power supply and see if there is any change in the noise or if you can hear the lift pump working.
In 280,000 miles and 22 years I've been through 5 lift pumps and 1 main pump.  

Ok so I've just checked I can here my lift pump when I turn key when I start the car in getting the noise coming from the main pump whiningthen when o disconnect lead on lift pump the same noise is still there I'm guessing main pump change

Bloody phone spelling lol

scotty b said

Ok so I've just checked I can here my lift pump when I turn key when I start the car in getting the noise coming from the main pump whiningthen when o disconnect lead on lift pump the same noise is still there I'm guessing main pump change

No, if the main pump is whining, it is whining because it is working harder than was designed for.

Just because you hear the  pump, doesn't mean it is pushing fuel to the main via the sump/filter/swirl pot that is affixed to the right side of the tank. As a matter of fact, the fuel system primes at key on, that it is runs for 4 seconds, and the throbbing you hear at key on is to tell you that the fuel system is primed, and usually it will eliminate a Vapor Lock condition and ease starting.

Disconnecting it and still hearing the noise doesn't mean that your main is bad, it only verifies that you have an obstruction to the main.  I mean the main could still be bad, but whereas the main pump is between 120 bucks and 240, the lift pump is only 50-80.

I have 189K on one of my Cabriolets, and I have been through 3 lift pumps and no primary ones.

I had about 190 on another one of my cabbies and the Main pump decided to quit 2 weeks before Christmas, and I did the single pump conversion…for 80 totally.

I would strongly urge you to replace the in-tank pump and filter screen first, give it a go.

Per the Bentley the in-tank and primary pump on a 90-ish Digi car are both the same working pressures and flow rate.

It is just my experience in them that tells me the intank pump is either Dead, or the interconnect hose is holed or broken.

When replacing the in-tank pump replace the interconnect hose/dampner with a piece of fuel rated
hose 5/16" IIRC.


 

What he said ^^^^^^.  

   If your main pump was dead and you disconnected the lift pump you would have no pumps working and the car will stop.

Ok guys thanks for all your info I think I'm going to replace both tomorrow anyway as due to a very good mate I've only paid £60 for bosch pump and £20 For the lift pump as he works for car part company lucky me.
hopefully it may fix my issue