Whine under Partial-Throttle Acceleration

Nomake Wan · #1 07-31-2007, 06:51 AM

Okay guys, here we go. My #1 problem at the moment, now with more video.

This happens in the SVX at 3000 RPMs, under partial throttle when accelerating. Happens in any gear (easier to get to happen in higher gears because they're longer and revs are lower). What happens is you press the throttle, and when the engine gets to about 3000 RPMs a high-pitched whine happens. This lasts for a couple hundred RPMs but once you get around 4000 it vanishes (or is perhaps just drowned out by the sound of the engine).

The funny part is, this exact same thing happened in my old 1990 Subaru Legacy L sedan. And that car has a 2.2L Boxer and was FWD! In the Legacy it began around 2500 RPMs and ended around 3500, though. It made the exact same sound. Now I know the SVX transmission is different from my Legacy's (the Legacy's wasn't as smooth and 'luxurious' on shifts like the SVX, and the SVX is AWD), and I know the engines aren't the same either (Legacy is EJ22 SOHC, SVX is EG33 DOHC). But then what could it be that would make the exact same sound in these two cars?

Since a picture is worth a thousand words, I figured I'd go for the million and took some video footage of the sound in my SVX.

http://youtube.com/watch?v=dy-Y1Ugq7pY

Listen carefully right when it hits 3000 RPMs. That whine is what I'm talking about. I have more videos, but it'll take me a while to get them all processed and uploaded. That video should do nicely to demonstrate my problem though.

EDIT: Here's another video, this one's longer so it does it a lot more.

http://youtube.com/watch?v=sQ6JBEKFB-E

In this one, every time it gets to 3k the whine happens and then above and it seems to go away. Below and it doesn't exist. Weird...

Here's hoping there's a guru out there who knows exactly what this is!

SVX_MY_BABY · #2 08-09-2007, 03:37 PM

Gotta tel ya. I can't hear it. Then again hearing goes as you age.

Mine make a sort of whine which is a bit like a turbo (but not really) under hard acceleration. Always has since new and I've always been curious what causes it.

SomethingElse · #3 08-09-2007, 04:09 PM

sounds like differential..front or rear. have you checked fluids?

Nomake Wan · #4 08-10-2007, 03:16 AM

It did it since I got it, even immediately after the front and rear diff fluids were changed. My old car did it too...

Any way to check the diffs for damage? Would a Subie dealer be able to do that? The fluids are good, I know that for a fact... and the sound comes from the front, not the rear. Came from the front in my old Legacy too.

SomethingElse · #5 08-10-2007, 04:36 AM

You can simply smell the fluid to check if its been overheated. the best way to do it is chassis ears. they clamp on onto anything and go through an amplifier with some headphones..found bearings that way b4.

ItsPeteReally · #6 08-10-2007, 08:56 AM

Quote:

This happens in the SVX at 3000 RPMs, under partial throttle when accelerating. Happens in any gear

Well it's most unlikely to be the differential. If it was, it would most likely be dependent on road speed not engine speed.

You are in luck, because the same noise should be evident when you are stationary, so you can get your head right up to the engine and listen.

If you can't pin down where the noise is coming from, you can localise the noise by putting a screwdriver (or similar object) on a suspect part and holding the other end against your ear (you've not got long hair have you? --- if you have, be careful!!!

) This cheap 'n' cheerful stethoscope is a great discriminatory tool.

I'm not a betting man, but the power steering pump might be worth a listen.