Hey Guys, Today I noticed that when my car is running (Idling) there is a hissing sound coming from what seems to be the EGR valve. It is not effecting the way the car runs or idles. But when I pull out the PCV valve and put my finger over the hole on the bottom of the PCV valve, the hissing stops. When I put the PCV back in, it hisses again. Is this normal? I just never noticed it before. How hard is it to change the EGR valve? It looks difficult to get to (5.7 TPI) Any help would be appreciated.
Thanks!
Mike

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Check out My Car Pics http://albums.photo.epson.com/j/Albu...667&a=13599419

Gran Turismo Americano "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber) & AC Delco Rapid Fire Plugs; Removed Smog Pump and all other Smog related parts.

 

GTA,

An EGR valve that is leaking internally will not generally cause a "hiss", since the ports are completely within the intake mainfold. Any leak large enough to make any apparent noise would also cause the idle to be very poor, and the engine might not idle at all. My guess is that the EGR is not leaking significantly.

It is more likely you have a different vacuum leak, or are hearing the IAC passing the normal amount of air through the throttle body. The difference in the amount of air entering the engine when you plug the PCV valve would cause the IAC to open more to compensate and maintain idle speed. This intake flow could cause the IAC to change position enough to eliminate the noise.

You might also have a different vacuum leak somwhere that changes pitch or volume when the PCV is plugged, as detailed above. Chak all hoses for cracks and splits, since they tend to make the most noise when leaking.

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Later,
Vader
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If you want to beat the World, it might reach up and pull you down...
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Thanks Vader! I will check the other vacuum lines again. The car is idling fine. Maybe it has always made that noise, and I never noticed it. I just think I would have noticed it. Hopefully I can find a leaky vacuum line and find out thats all it is.
Thanks again man
Mike

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Check out My Car Pics http://albums.photo.epson.com/j/Albu...667&a=13599419

Gran Turismo Americano "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber) & AC Delco Rapid Fire Plugs; Removed Smog Pump and all other Smog related parts.

 

I agree with Vader, if the diaphram was ruptured, it would cause the car to run worse, set a code and the EGR doesn't get vacuum at idle anyway. If it goes away when you cover the PCV, it's probably not a vacuum leak. I bet it's a normal condition.

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Kyle Osterholt
Okarche, Oklahoma
ASE Master Certified
86 T/A 383 TPI
89 TTA #1002 T-top/Leather
89 TTA #1358 Hardtop/Leather
80 T/A Pace Car
73 Opel GT
73 bronco
2000 Ducati 996 Monoposto
83 MSE #52

 

Thanks Snakeskinner for the advice also.

Mike

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Check out My Car Pics http://albums.photo.epson.com/j/Albu...667&a=13599419

Gran Turismo Americano "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber) & AC Delco Rapid Fire Plugs; Removed Smog Pump and all other Smog related parts.