Vacuum sound when accelerating

GATitan · 08-05-2004, 09:48 AM

Has anyone noticed a vacuum or hissing sound right at the beginning of acceleration? It is more noticeable when I am on the interstate doing about 65mph and I hit the gas to accelerate. It makes the noise for a split second and then the car accelerates. Didn't know if this was normal or not. Any comments would be appreciated.

GATitan · 08-05-2004, 09:53 AM

Don't confuse this with the AC hissing issue, different sound. Thanks

GETSOMZ28 · 08-05-2004, 10:24 AM

Dont have that here. The only other "whooshing" noise I have is the clutch fan that comes on occassionaly that is pretty loud (and sucks power).

RS250R · 08-05-2004, 12:00 PM

my fan clutch is noisey too!!! need to add that to my list

ensclark · 08-05-2004, 12:08 PM

Has anyone looked in to going with an electric fan and getting rid of the cluch fan. Better gas mileage and HP wouldn't it?

the head · 08-05-2004, 01:41 PM

Yeah actually Jegs is offering a $10 discount on a certain brand of electric fan. I was considering it. But I decided to spring for foglights this month instead.

Titanman · 08-05-2004, 04:55 PM

That's the normal sound of the air swooshing into the airbox. Open the hood and listen as you give it a couple blips of pedal.

MIke

JetTech · 08-05-2004, 05:20 PM

Quote:

Originally Posted by Titanman

That's the normal sound of the air swooshing into the airbox. Open the hood and listen as you give it a couple blips of pedal.

MIke

Could be, just to be on the safe side though check to make sure your air-box and intake air duct is all connected and latched.

IMADOGMAN · 08-05-2004, 07:42 PM

Quote:

Originally Posted by GATitan

[SIZE=2]Has anyone noticed a vacuum or hissing sound right at the beginning of acceleration? [/SIZE] It is more noticeable when I am on the interstate doing about 65mph and I hit the gas to accelerate. It makes the noise for a split second and then the car accelerates. Didn't know if this was normal or not. Any comments would be appreciated.

That vacuum sound is just the sound of your money being sucked out of your wallet by one of the major petroleum retailers...when you take your foot off of the accelerator, it stops......right?

GATitan · 08-09-2004, 06:40 AM

Quote:

Originally Posted by IMADOGMAN

That vacuum sound is just the sound of your money being sucked out of your wallet by one of the major petroleum retailers...when you take your foot off of the accelerator, it stops......right?

So that's what that sound was!!!

Thanks to all for your responses, I feel better about the issue, I think.

the head · 08-09-2004, 10:01 AM

The K&N drop-in also makes said whooshing noise. I never hear it with the stock air filter, but I do now.

Steamguy · 08-09-2004, 02:08 PM

That's the sound of the manifold vacuum being dumped. The engine hasn't caught up to it yet so you hear a loud whoosh.

Old cars with badly calibrated carburetors used to make this sound also. -Right before a backfire.

What happens in the Titan:

-Throttle snaps open (whoosh sound)

-Sometime after that the engine computer gets the message the throttle has opened and gives the fuel injection an extra shot to compensate

-Sometime after that the system catches up to the acceleration and away you go

In the second step, the engine computer isn't sampling the throttle position often enough, so you have that lag when you jam the gas.

If this were a carbureted vehicle, that sudden loss of manifold vacuum (extra air) would cause a major backfire through the carb without an extra shot of gas.

Instead, the O2 sensor loop just says, "Oops, too lean..." and the computer compensates immediately until it gets the throttle position information.

Hope this helps.

Nuckle · 08-10-2004, 05:54 AM

This beast needs a lot of air to run. When I really get on it I can hear it sucking air in and it almost sounds like some type of FI.

Nuck

GATitan · 08-13-2004, 07:31 AM

Quote:

Originally Posted by Steamguy

That's the sound of the manifold vacuum being dumped. The engine hasn't caught up to it yet so you hear a loud whoosh.

Old cars with badly calibrated carburetors used to make this sound also. -Right before a backfire.

What happens in the Titan:

-Throttle snaps open (whoosh sound)

-Sometime after that the engine computer gets the message the throttle has opened and gives the fuel injection an extra shot to compensate

-Sometime after that the system catches up to the acceleration and away you go

In the second step, the engine computer isn't sampling the throttle position often enough, so you have that lag when you jam the gas.

If this were a carbureted vehicle, that sudden loss of manifold vacuum (extra air) would cause a major backfire through the carb without an extra shot of gas.

Instead, the O2 sensor loop just says, "Oops, too lean..." and the computer compensates immediately until it gets the throttle position information.

Hope this helps.

Steamguy, Thanks for the extra info. Is this normal for the Titan or should I take it in and get it repaired.

Thanks

kbutton · 08-22-2004, 03:10 PM

I had the "vacuum" sound in my first Titan. It was constant as long as I was accelerating.

Dealer and Nissan could not fix - so owner gave me a second Titan!

Now, my second Titan has been in the shop for multiple problems over 45 days!

I filed for lemon law. I am getting out while I can.