High Pitched Rattle

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  #1  
Old 11-01-04, 10:11 PM
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High Pitched Rattle

Hi -

1988 Camaro, 305, Vin E, Throttle Body Injection. 138,000 Original miles on the engine.

I recently began hearing a high pitched intermittant very fast chattering in the top right area of my engine. When it happens on its' own, I can usually increase the RPM a bit to make it go away. Other times, when I increase RPM, it happens then too. HELP!!!

It sounds very much like the sound when end link bushings are worn and the washers are bouncing around. I know it's not this because I changed them. Plus, it just sounds internal. I haven't yet been able to pinpoint it as it seems to only want to do it when I'm inside the car and when mechanics are not present!

I was thinking worn spring or rocker arm, or something loose in there, but my mechanic said it would be more of a slapping sound. But the sound is almost certainly coming from the head area. How about a loose valve guide? I know I need to probably replace the heads...wanted to anyway to get something better than these notorius stock doggies.

Thanks in advance!!

Maitai
 
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  #2  
Old 11-02-04, 04:43 AM
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first...

...you must figure out how to repeat it on demand...with or without a load and at what RPM. then you can use the process of elimination. try running it without the serp belt to eliminate any accessory vibrations...you could have a cracked bracket or loose or missing fasteners. if the noise goes away with the belt removed, it's not internal...in fact, i'd be surprised if it is...what you're describing doesn't sound typical for an internal engine noise.

you might also purchase a mechanic's stethescope and try to localize it that way...
 
  #3  
Old 11-02-04, 06:10 AM
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I am cheap

I use a piece of garden hose to find the noise.
 
  #4  
Old 11-02-04, 06:26 AM
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Originally Posted by carguyinva
try running it without the serp belt to eliminate any accessory vibrations...
Whats the longest one should try doing this? a couple minutes, seconds?
 
  #5  
Old 11-02-04, 07:59 AM
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not to long

I would not do it very long since the water pump will not be working I would not go over a min.Just long enough to find the noise also you might need a helper to keep a eye on the temp guage and start the car so you can get right on finding the noise.
 
  #6  
Old 11-02-04, 01:09 PM
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Check the egr system and make sure the cooling system is full sounds like it may be detonation.
 
  #7  
Old 11-03-04, 12:31 PM
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Why the EGR system? I did change the valve, hose, and solenoid. However, I am still getting an EGR failure code on my PROM...
 
  #8  
Old 11-03-04, 02:09 PM
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Originally Posted by maitai11
Why the EGR system? I did change the valve, hose, and solenoid. However, I am still getting an EGR failure code on my PROM...
Interesting new tidbit of information comes to light.If the EGR system does not function properly the engine can and will detonate or ping, valves rattle how ever you want to say it.Did you clean the egr ports?What code # is present?
 
  #9  
Old 11-03-04, 10:59 PM
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It's a code 32 and I've tried all of the above to fix it. Don't know specifically how to clean the passageways, although they looked clear at the time of install. I would really appreciate some help if you're knowledgeable about the way this thing works and how I can solve this problem. Thanks for everything so far Davo and all who responded!!

Maitai
 
  #10  
Old 11-04-04, 04:32 AM
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the most helpful thing...

...would be to obtain a copy of the EGR system check for that vehicle. it will check all aspects of operation and lead you to the correct fix. try your local library...or aftermarket manuals at your local parts distributor.

PS...we seem to have zeroed in on a particular problem here...(pinging/detonation)...which it may be. detonation is always load related and is usually caused by one of three things...operating temp, incorrect ignition timing or EGR malfunction. a good tech always verifies the complaint before acting...which is hard to do in this medium...so do what you can to be sure you are following the correct pathway here...or you could spend alot of time on the above issues only to find a loose bracket bolt or something goofy like that. the fact that you have a code 32 is telling...follow up on that first but don't lose sight of the bigger picture.
 
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