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Item Posts    Sort Order

Whining noise... fuel pump, lights?

 
Roslynvs
New User
Posts: 9
Joined: 06/13
Posted: 06/30/13 11:31 AM

I have a 69 coupe. Which I have had for about a month. When I bought it there was a whining noise coming from the rear left hand side of the car. The guy I bought it from said that it was the fuel pump which was mounted on the floor pan that was making that sound, he said the guys that mounted it didn't put on the rubber mountings so he said I just needed to put them on and it would stop. I had a look and it seems like the mountings are on. When I turn the key half way in the ignition the whining starts, when I turn the key full the sound continues but I have noticed that when I switch the lights on the sound changes slightly and gets louder, switch them off and it goes back to the original sound. Any ideas at all as to what is going on here?  

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waynep712222
User
Posts: 223
Joined: 04/13
Posted: 06/30/13 01:01 PM

do you have a hand held digital volt meter? if you do.. lets do a voltage drop test..

this whole test takes about 5 minutes to perform.. since your battery is fully charged.. more than likely.. you might want to start at the second half of the test...

this should be a printable image.. so you can take it to the car to follow exactly..
~~~~~~~~~~~
Voltagedroptesting

~~~~~~~~~~~~~~~  

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waynep712222
User
Posts: 223
Joined: 04/13
Posted: 06/30/13 01:10 PM

on all cars.. there should be multiple wiring connections...

lets start on the negative side.. since electrons flow from negative to positive..

there is a thick negative battery cable from the terminal to the engine block...
there should also be a smaller wire from the negative terminal to the inner fender..

there NEEDS to be a braided ground strap from the back of the engine block to the firewall... and it needs to be attached properly... test 4 will tell if this is an issue..

some fords have a mounting tab part way down the negative battery cable.. that if you look closely is actually the negative battery cable to body ground connection....

wait... i have not answered your question to why the electric fuel pump changes sound when you turn on the headlights..

the headlights put additional loads on the wiring system.. causing the voltage to the electric fuel pump to change...

what i am attempting to get you to run are tests to verify the ground side of the system is properly HOOKED UP... as i said before.. electrons flow from negative to positive..  

if you don't have the 3 ground connections hooked up properly.. you may not have enough electrons to power all the circuits properly..  

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waynep712222
User
Posts: 223
Joined: 04/13
Posted: 06/30/13 01:12 PM

this is only the starting point..

65 66 Mustang Ground Cables  

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Roslynvs
New User
Posts: 9
Joined: 06/13
Posted: 06/30/13 05:43 PM

Hi Wayne,
Thanks for all the advice. I don't have a volt meter but I am sure my dad does I will ask him in the morning ( it is 2:40 am here at the moment) so glad you put a picture up because I know nothing about cars and am learning as I go but I am sure I will be able to follow the pics. Do you think that the fact that the fuel pump whines all the time would also be a voltage issue?  

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waynep712222
User
Posts: 223
Joined: 04/13
Posted: 06/30/13 06:11 PM

change in noise is an issue... showing there is an issue in the circuitry..

whining is kinda normal.. with electric fuel pumps... they are always wining about wanting to go faster...

actually restriction like a clogged fuel filter will cause the pump to work harder and whine..

low fuel levels cause the pump during normal operation to run dry..  since pumps are lubed and cooled by the flow of fuel going thru them..  any air will cause the pump armature to overspeed.. can cause damage to the brushes and commutator..  the commutator is the segmented brass contacts that connect the spinning armature to the brushes..

low fuel levels and air going thru the pump can also wear out the ceramic bearings when the pump motor overspeeds because of the air going thru ..

there are several ways to mount fuel pumps... depending on which one you have..

i have gone as far as dangling fuel pumps from some exhaust hanger bushings where they have 2 bolt holes in a molded ring type device..  

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Roslynvs
New User
Posts: 9
Joined: 06/13
Posted: 07/07/13 05:46 AM

Thanks Wayne,

My dad didn't have a volt meter but my car has gone to the mechanic to install the power steering so I have asked him to check it out.

Ros  

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70bird
User
Posts: 86
Joined: 07/13
Posted: 07/07/13 09:32 AM

Hello Roslynvs


Sounds like the lights are simply drawing current from the pump. When this happens the pump spins more slowly, when it spins more slowly they can often make more noise, just he nature of some of them. I had this exact issue many times, should not be a problem providing the size of the wire going to the pump is adequate.

Some pumps have brackets that isolate them better form the body thereby reducing the noise.  

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