Hey, glad you asked that. I'll share some information from a very high-level Carquest trainer and some from my own experience.
Chrysler fuel pumps are extremely quiet. That is due to the very tight clearances they are built with. Replacement pumps from NAPA are just as quiet because they come from the same supplier that Chrysler gets them from. The downside is due to those tight clearances, microscopic debris in the tank has a better chance of clogging the impeller. When Chrysler pumps fail, they almost always fail to start up when you try to start the engine. It is unheard of to have one of them quit while you're driving. Worn brushes in the motor also cause intermittent no-starts. Banging on the bottom of the tank usually gets them going, and it can be weeks before that happens again. Repeated failure of new fuel pumps is caused by that debris in the gas tank. Removal and steam cleaning by a radiator repair shop solves that relatively uncommon problem. People blame the new pumps because they quit after a week or two, but the problem really is that debris in the tank, not the new pumps.
Compare that to GM fuel pumps. They do not have those tight clearances so the impeller doesn't get stuck. The trade-off is they are much noisier. You can hear the truck fuel pumps running from a long distance. Cars aren't quite so bad. Unlike the Chrysler pumps, GM pumps are noted for stalling while they're running, so they let you sit on the highway. When the Chrysler pump fails, you're still at home or at the store, not on the side of the road.
The fact that you're hearing the pump now and you've observed that it sounds different than before is not serious in itself and does not necessarily mean it's about to fail, but that's assuming it really is the pump that's making the noise. The fuel pressure regulator could be vibrating and buzzing. The concern isn't the noise, it's the fact the noise changed.
A totally different problem could be if your car has an automatic load-leveling system in the back. My Dynasty has that and I can hear the pump run each time I start the engine, (which is about once every other year!). That doesn't make a whining noise though. I was trying to think how that could be related to a cruise control problem, and came up blank.
My best recommendation is to have a mechanic take a quick listen to find out if it really is the fuel pump you're hearing. Most of them will run out and do that for you if they aren't busy or have a customer waiting for their car.
I see quite a few GM vehicles sitting on the highway I travel that suddenly stopped running, and quick checks usually show a lack of fuel pressure and suspected failed fuel pump. That rarely applies to cars though. It almost always involves full-size trucks and newer models from about the last eight years. Obviously that could be because there's a lot more newer trucks on the road than there are '90s model cars. I don't see many other brands of vehicles stalled on the side of the road but they all have fuel pumps that quit at some point.
Without knowing more details, my suggestion is to take it on your trip, but if you'll be traveling with another car or truck, stick close together in case of trouble. The fuel pump in my rusty '88 Grand Caravan started making a noticeable high-pitched whine about two years ago but it hasn't skipped a beat. I've made three cross-country trips with it like that. I can't hear it inside the van. As long as it keeps on running, I'll keep on driving!
Monday, August 1st, 2011 AT 1:16 AM