Whistling noise - ZR-1 Net Registry Forums

1991KOTH · 03-20-2019

Hey guys, my Z just recently started to get a whistling noise. It only really happens when the car is warmed up and gets louder when I hit the gas. Any ideas?

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A26B · 03-20-2019

Vacuum leak.

1991KOTH · 03-20-2019

Quote:

Originally Posted by A26B

Vacuum leak.

Yep, just checked the MAP sensor lines and all was good. I fear I may have to pull the plenum again. Will most likely get rid of the secondaries and do the coolant bypass once Im in there. Sounds like its coming from this general area. Will have to investigate further.
IMG_7940.jpg

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Jagdpanzer · 03-20-2019

Ive had mis-aligned air horn bellows hose clamp come in contact with the AC pulley make a similar high pitch noise to a vacuum leak.

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Ccmano · 03-20-2019

The alternator can make a whine or whistle (I guess). Hard to say without hearing it.
H

ZWILD1 · 03-20-2019

This is interesting. Not long after Carlisle this year my car started to make a whiny kind of noise. My car has no secondary as Marc H did one of his 510 packages. It's not a vacuum leak as the idle has been checked and Marc said it's ok. I checked the bellows clamp and that is ok also. Not sure what else it could be though. I think the idle was around 770 but Haibeck said that wasn't all that out of line. To me it sounds like the driver side area of the plenum but it's hard to tell really.

XfireZ51 · 03-20-2019

A vacuum leak would very likely cause an oscillating idle. And it would idle higher.

1991KOTH · 03-20-2019

Quote:

Originally Posted by XfireZ51

A vacuum leak would very likely cause an oscillating idle. And it would idle higher.

Idles at about ~800 when cold but “searches” for a bit when Im coming to a stop and put the clutch in. When it warms up the idle can be quite erratic. Check engine light also comes on and off at times. Gonna have to put a piece of cardboard up to the airhorn and see if the engine stalls out tomorrow.

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XfireZ51 · 03-20-2019

Quote:

Originally Posted by 1991KOTH

Idles at about ~800 when cold but “searches” for a bit when Im coming to a stop and put the clutch in. When it warms up the idle can be quite erratic. Check engine light also comes on and off at times. Gonna have to put a piece of cardboard up to the airhorn and see if the engine stalls out tomorrow.

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Yes I would block the airhorn. Idle hunt when coming to a stop w clutch disengaged is not unusual and not necessarily indicative of a vacuum leak. See if SES has a code to it.
What are the conditions that have SES come on?
If idle oscillates w warm engine, could be vacuum leak.

ZWILD1 · 03-21-2019

My noise is there cold when you first start the car and it remains when hot. About a month before Carlisle I did a service on the K&N air filter and it was fine. The car sat three or four weeks after Carlisle and then I went to start it and the noise was present. Marc Suggested I try and put a towel over the air box on top of the filter and see if the noise changes. It has the replacement PCV hose assembly ( non factory style ) and Marc put small plastic ties around them to make sure they are sealed and don't come loose.

03-20-2019	#1
1991KOTH Join Date: Nov 2016 Location: Florida Posts: 65	Whistling noise Hey guys, my Z just recently started to get a whistling noise. It only really happens when the car is warmed up and gets louder when I hit the gas. Any ideas? Sent from my iPhone using ZR-1 Net Registry

03-20-2019	#2
A26B Join Date: Dec 2003 Location: Arcadia, OK Posts: 3,402	Re: Whistling noise Vacuum leak. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.

03-20-2019	#4
Jagdpanzer Join Date: Apr 2007 Location: Northern VA Posts: 2,651	Re: Whistling noise Ive had mis-aligned air horn bellows hose clamp come in contact with the AC pulley make a similar high pitch noise to a vacuum leak. Sent from my iPhone using ZR-1 Net Registry __________________ Phil Wasinger 1994 Torch Red ZR-1 WAZOO Member George Braml Intake

03-20-2019	#5
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,843	Re: Whistling noise The alternator can make a whine or whistle (I guess). Hard to say without hearing it. H

03-20-2019	#6
ZWILD1 Join Date: Aug 2004 Location: Spring Grove ,Pa. Posts: 258	Re: Whistling noise This is interesting. Not long after Carlisle this year my car started to make a whiny kind of noise. My car has no secondary as Marc H did one of his 510 packages. It's not a vacuum leak as the idle has been checked and Marc said it's ok. I checked the bellows clamp and that is ok also. Not sure what else it could be though. I think the idle was around 770 but Haibeck said that wasn't all that out of line. To me it sounds like the driver side area of the plenum but it's hard to tell really. __________________ 91 Turquoise Metallic Haibeck 525 #0134

03-20-2019	#7
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,686	Re: Whistling noise A vacuum leak would very likely cause an oscillating idle. And it would idle higher.

03-21-2019	#10
ZWILD1 Join Date: Aug 2004 Location: Spring Grove ,Pa. Posts: 258	Re: Whistling noise My noise is there cold when you first start the car and it remains when hot. About a month before Carlisle I did a service on the K&N air filter and it was fine. The car sat three or four weeks after Carlisle and then I went to start it and the noise was present. Marc Suggested I try and put a towel over the air box on top of the filter and see if the noise changes. It has the replacement PCV hose assembly ( non factory style ) and Marc put small plastic ties around them to make sure they are sealed and don't come loose. __________________ 91 Turquoise Metallic Haibeck 525 #0134