engine noise
Thread Starter
Instructor
Joined: Jul 2006
Posts: 141
Likes: 0
From: New York
engine noise
I heard this sound once before now it happens at every start up for about 30 seconds and goes away. Basically everytime I start my 99 A/T I get this wobbling sound. The balancer looks like it has a very slight wobble to it but that could also be eyes playing tricks. It is a mix between a drone/high pitched hum and it definetly has a high/low wobble sound to it. Although it sounds like the balancer, it seems to be coming from the back of engine. Any ideas?
Thread Starter
Instructor
Joined: Jul 2006
Posts: 141
Likes: 0
From: New York
Just realized that it only happens when the car is hot. Starting to think it is the starter because it is coming from that side of the engine from behind and under. Hopefully someone chimes in, it would be pretty funny if I talk myself into solving my own issue.
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
We're going to need more info. how many miles on the car? Anything done to the car recently? Does it do it in park, in gear, at a stand still? while driving? what makes it worse or louder? what makes it better if anything? Does the noise change with engine speed or vehicle speed?
Thread Starter
Instructor
Joined: Jul 2006
Posts: 141
Likes: 0
From: New York
Ok car is a 98 with 75K. Just put in longtube headers and ls6 manifold. On cold start all is good. Once it starts to warm up every time I start I get this rotory noise for exactly 20-30 seconds regardless applying throttle, in gear or moving.
Burning Brakes
Joined: Dec 2003
Posts: 1,066
Likes: 9
From: Eddy Texas
Could be a "fluttering" as air leaks past the AIR check valve. That system only runs for a few seconds on start up.
Any DIC codes? p0410,p1415,p0492?
http://forums.corvetteforum.com/show...ght=Code+P1415
Read this thread and you'll have a real good idea of what to do if the AIR system is the problem.
Any DIC codes? p0410,p1415,p0492?
http://forums.corvetteforum.com/show...ght=Code+P1415
Read this thread and you'll have a real good idea of what to do if the AIR system is the problem.
Thread Starter
Instructor
Joined: Jul 2006
Posts: 141
Likes: 0
From: New York
OK. It is 100% the air pump. Thanks for the link! Since I put on headers, I no longer have the pump connected to the old header. I went outside and realized when I blocked the hose blowing air the noise stopped. Since my car does not use this anymore, could I just go and remove the air pump electrical connection disabling it? Will this be ok or will it cause other problems?
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Thread Starter
Instructor
Joined: Jul 2006
Posts: 141
Likes: 0
From: New York
Thanks very much. I was planning to get the car tuned as well as get the check engine light off. Next weekend I will go and pull out the wire for the pump and call it a day. Thanks a lot !
