more s2k songs

[omniruss]

So many sounds, so many threads, so here's another! I feel I can't put these off much longer and I need to start diagnosing them...

1) I've been procrastinating this one for a long time, and it's really starting to bug me. I think my rattle is coming out of the engine bay. I only hear it around 1800 to 2000 rpms. It's obvious when I start the car with a warm engine, but it seems to remain quiet when I start the car in the morning. I thought it only happened on start-up, but I recently noticed that when the top is down and I have a nice hard barrier to reflect the sound on my left side while I'm driving, I can still hear it as I hover at 2000 rpms or just below. Not sure how to describe the sound, but it's apparently tied to the rpm rate of the engine... any hunches?

2) After I've driven the car for at least 4 hours, I can hear what I believe to be the whine of the fuel pump since the noise seems to originate from the fuel tank. It's the pump that came with the Comptech s/c kit. My first concern is that it might decide to quit working after I've driven 300 miles away from home. But after the car sits overnight, the noise goes away until after I drive another 4 hours back home. I'm assuming the pump is exceeding its 'normal' operating temperature, what do you think? Cause for concern?

[repiv]

1. Your rattle may be oil related (or lack of). When cold starting, the engine is momentarily oil starved (a second or so). When hot, it can be thin oil and low oil pressure at 2000 rpm. This can produce a similar situation to slight oil starvation.
Next time you hear it, see if you can make it go away with a small increase in rpm, which would elevate oil pressure slightly and increase oil flow. I'm thinking you may have valvetrain noise. That's a lot of moving parts that will rattle if oil flow is reduced. It could also be the onset of timing chain tensioner issues. This one will only get worse with time.
You should also check the serpentine belt tensioner. It can also make a ticking sound if it's on the way out.
Any one of the engine accessories with a pulley can rattle, too. The A/C compressor has an electric clutch mechanism. Can you say if the rattling is associated with A/C use?
Something similar can be said about the alternator, though this one is more remote.
If you have a discerning ear, go under the hood when this noise is evident and operate the throttle with your hand at the throttle body to see if you can make the noise happen. If you can, then you might be able to "home in" on where exactly it's coming from. Valvetrain noise will be generalized on the top of the engine. Timing chain tensioner will come from the front of the engine on the right side, near the top of the block, bottom of the head.
Now, with Comptech blower running, you might have blower bearing noise, too. The CT blower normally sounds like a tin can with nuts and bolts inside, so you'll have to determine if this rattle is something new.

2. Virtually all CT and VT high output fuel pumps do what you say. From time to time, they will whine like a mofo. There is no rhyme or reason to it. I once thought it did it when the fuel tank was getting low since all modern day electric fuel pumps require fuel as a coolant and for self lubrication. I discovered that it does it even with a full tank of gas. I have now concluded that this is a normal thing for these HO pumps. I hope I'm not wrong when I say there's nothing to worry about. So far, at least, all's good and it's been over 5 years.

[raymo19]

2. Virtually all CT and VT high output fuel pumps do what you say. From time to time, they will whine like a mofo. There is no rhyme or reason to it. I once thought it did it when the fuel tank was getting low since all modern day electric fuel pumps require fuel as a coolant and for self lubrication. I discovered that it does it even with a full tank of gas. I have now concluded that this is a normal thing for these HO pumps. I hope I'm not wrong when I say there's nothing to worry about. So far, at least, all's good and it's been over 5 years.

Amen Brother Dave.:D

There were times I attributed it to tire noise or some harmonic from the 4.57s but when you pull into a rest stop and the damn thing whines like that at idle and again when you crank it back up after the conclude of business it's pretty obvious where the sound is coming from.:rofl:

AFAIK I've had no fuel issues - it's just another noise you hear from time to time. Just another reason I don't play the crappy stereo much and don't plan to upgrade it.

[repiv]

A small, somewhat related anecdote ......................
My stock '94 Dodge Viper used to do the same thing. Once in a while, the fuel pump would crank up like a jet engine. I thought it was on the way out. It did this the very first year I had it. 3 years later, I sold it and the fuel pump was still just fine. I see the car annually at the car show where the guy I sold it to still uses it as his "company" car for displaying his alarm systems. He indicates to me that nothing on the car has ever broken and needed replacing. I'm beginning to think the some high output fuel pumps just do this.