Notices
928 Forum 1978-1995
Sponsored by:
Sponsored by: 928 Specialists

86 intake whistle

Thread Tools
 
Search this Thread
 
Old 03-18-2015, 10:07 AM
  #31  
Dadddio
Instructor
Thread Starter
 
Dadddio's Avatar
 
Join Date: Aug 2012
Location: St. Louis, Missouri
Posts: 234
Received 1 Like on 1 Post
Default

Haven't done anything.
It's at the shop having the aero-mirrors and rub strips painted.
Should have it back soon.
Gonna check the TPS and a few other things.
Needed a break anyway, it was getting very frustrating.

Maybe the intake leak was so bad, there was not enough of a pressure buildup to send the smoke out the small leaks. We may have the throw the smoke machine back on there if you continue to have issues.
Mike, I may take you up on that.
I'll let you know.
Old 10-25-2016, 12:08 AM
  #32  
porsche928guy
Racer
 
porsche928guy's Avatar
 
Join Date: Mar 2005
Location: Leawood, KS
Posts: 314
Likes: 0
Received 0 Likes on 0 Posts
Default

So what eventually solved your issue? I'm chasing a similar whistle combined with a significant miss at idle that smooths out around 2k rpm. This is after an intake powdercoat/refresh.
Old 10-25-2016, 08:32 AM
  #33  
Dadddio
Instructor
Thread Starter
 
Dadddio's Avatar
 
Join Date: Aug 2012
Location: St. Louis, Missouri
Posts: 234
Received 1 Like on 1 Post
Default

It was a vacuum leak.
I ended up running a smoke test on it.
It turned out to be several small leaks from driver side intake gasket.
Had some gaskets special made....the whistle stopped.
Hasn't whistled since....knock wood.

Old 10-25-2016, 11:24 AM
  #34  
MarkRobinson
Addict
Rennlist Member
 
MarkRobinson's Avatar
 
Join Date: Mar 2005
Location: Austin, Texas
Posts: 2,301
Likes: 0
Received 3 Likes on 2 Posts
Default

For my issue, the Powdercoating of the intake runners had warped the flanges that mate to the intake ports of the head, so I had to remove the intake & put the runners on a belt sander to re-flatten. One was so bad you could see light under it & it failed the vacuum/smoke test.
Old 10-25-2016, 11:30 AM
  #35  
SeanR
Rennlist Member
 
SeanR's Avatar
 
Join Date: Apr 2006
Posts: 35,700
Received 498 Likes on 266 Posts
Default

Originally Posted by MarkRobinson
For my issue, the Powdercoating of the intake runners had warped the flanges that mate to the intake ports of the head, so I had to remove the intake & put the runners on a belt sander to re-flatten. One was so bad you could see light under it & it failed the vacuum/smoke test.
Had one do exactly this a few weeks back. Took a good amount of time to get the mating surfaces flush so they would seal with the factory gaskets.
Old 10-25-2016, 11:44 AM
  #36  
MarkRobinson
Addict
Rennlist Member
 
MarkRobinson's Avatar
 
Join Date: Mar 2005
Location: Austin, Texas
Posts: 2,301
Likes: 0
Received 3 Likes on 2 Posts
Default

Exactly Sean. Exactly. My warp was at Runners 3 & 4 (#4). Used a Firework punk to find the leak, verified it with light as well: no wonder that sucker whistled so loudly!
Old 10-25-2016, 11:57 AM
  #37  
SeanR
Rennlist Member
 
SeanR's Avatar
 
Join Date: Apr 2006
Posts: 35,700
Received 498 Likes on 266 Posts
Default

Originally Posted by MarkRobinson
Exactly Sean. Exactly. My warp was at Runners 3 & 4 (#4). Used a Firework punk to find the leak, verified it with light as well: no wonder that sucker whistled so loudly!
I pressurize the intake and listen for the air with a mechanics stethoscope. If it holds pressure for a bit of time then it's good. If not, well ya leaking.



Quick Reply: 86 intake whistle



All times are GMT -3. The time now is 02:24 AM.