Hi. I just purchased an '87 Bonneville with a 3.8L V6 Engine. Love these
engines. This car has a strange noise coming from the rear. For just an
instant when you turn the car on, you'll hear the whir start. Then it stops
until the car is started. The noise is quite loud. It will sort of speed
up and slow down with the blinking of the turn signal which is what makes me
believe it's possibly the electric fuel pump at the back.
Anyone think this might be the problem? Any other ideas? It almost sounds
like a vacuum leak. Thanks!
One more symptom: The Gas Gauge is broken.
From what I've read on the internet, here is what I surmise happened: The
gas gauge broke, and whoever was driving it ran the car out of gas, not
knowing that they were out of gas. The opinions I've found on the internet
seem to suggest that if you run the fuel pump with no gas, that the motor
has no cooling and the bearings can wear out. Auto Parts store has the
sending unit and float assembly for $75. Anyone ever change one of these
bad boys? Any suggestions?
Check to find out if your car has had a NEW fuel pump installed before
you bought it. New pumps are much noiser than the original ones made in
87. Many times during re-installation of the fuel pump the float
mechanism is damaged and then your gas gauge don't work.
MY new pump I had installed a year ago makes a Whrrrring noise. Just
something you have to live with now adays.
1991 Pontiac Bonneville LE
3800 V6 ( C ), Black/Slate Grey
_~_~_~_~279, 354 miles_~_~_
I had the fuel pump start to go in my 87 Cavalier Z24. It started
sounding like a Bear molesting a Pitt-Bull. My rule of thumb with electric
fuel pumps: When in doubt change them before you get stranded. They will go
out with no warning. Old mechanical pumps usually got weak before they
If the fuel gauge does not register, it could be a bad wire. A bad
contract at the ssending unit, or a bad sending unit.
The sending units are ease to R&R as are the fuel pump. The real pain
in the rear in doing the gas tank with out a lift.
Gas Tank removial:
Lift and support car as high as possible on jack stands. Shake car front
both sides to make sure stands are holding before you climb under it. I do
shake tests on my lift if I ever have the slighest doubt.
Losen strap retaining bolts on gas tank. Supprt gas tank with floor
jack (i use a transmission jack) and remove straps. Lower slightly untill
you can remove wires and fuel lines. Then disconnect filler neck. Note some
cars require the exhaust system to be losened, or partially removed.
Lower the tank to the ground. Using a screw driver and a small hammer,
gently tap the retainting ring around. One it clears the lock tabs lift
Gently work the sending unit out, being carefull of the float & float
arm. Disconnect the pump wires. Pull off the pick up screan. Slihtlybend
down on the lower support tab. Slide the pump out.
Really installation is a reverse of removial. Use a good AC Delco pump,
and a new pick up screan. If you need to replace the entire sending unit,
you can get them cheep used.
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