rear of the car high pitch whine- heard inside while driving

[coogs]

ok- problem of the week- I've got this low tone- high pitch wine that seems to be attributable to the fuel pump?? at least that the only thing I can think of and it does it when I engage the fuel pump but do not start the engine- just turn over the ignition to AUX. If one was hard of hearing they may not hear it but its defiantley there and stays on when the car is running. Am I barking up the right tree and any suggestiions on how to diagnosis / fix- I'm not sure how to determine if it is the pump and when its time to repalce. 99 Lesabre

[HotZ28]

Does your car have Auto Level Control (ALC)? Fuel pumps can develop a "whine" if the fuel filter is blocked. When was the last time the filter was changed?

[coogs]

no ALC... your're obvioulsy talking about the in line filter- that would have been changed 12 months ago. 20K miles ago. Car drives fine - what do you suggest?
G

[HotZ28]

When you first turn the ignition ON, does the fuel pump run and then shut OFF after a few seconds? Have you checked the fuel pressure to see what the prime pressure is and if it will hold pressure without the switch on? You might want to change the in-line filter first, to see if that has an effect on the “whine”.

[coogs]

yes- the pump operates as you have described - and the whine is there and then shuts off when the pump shuts off. starts again when the car is running. haven chekced the pressure and not sure how but have the haynes manual so will chekc and I guess I need to get an appropiate pressure guage as well. hopefully not too difficult. I'll do as you've suggested with the filter- a good suggested start- thanks