diagnosis help?!?
05-10-2006, 10:44 PM
#1
Teching In
Thread Starter
Join Date: Jan 2006
Location: Chevy land
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
diagnosis help?!? i have a buddy with a 95 Z28 with 91k on it....the weirdest noise is coming from it....slowing down to almost stop then punching it once it gets to about ~5k it make this extremely rapid clicking noise(similar to if u take a stick and scrape it across concrete, but make it really loud and happen 3 times within a second). this doesnt happen all the time tho, we only go the noise to happen once we did as stated above. under normal driving conditions when hitting WOT nothing happens. he origionally thought it was a misfire but i doesnt sound anything like a misfire that i have ever heard. the only other thing abnormal about his car was his tail pipes were much blacker than normal..... any ideas? thanks for any and all help
05-10-2006, 11:02 PM
#2
12 Second Club
Join Date: Sep 2005
Location: Springfield, Missouri
Posts: 354
Likes: 0
Received 0 Likes
on
0 Posts
it sounds like knock. what kind of gas is he running? has he always used the same gas station? (does it sound like a spray paint can when you shake it best way to discribe it)
05-11-2006, 09:26 AM
#5
Teching In
Thread Starter
Join Date: Jan 2006
Location: Chevy land
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
do u think its just a bad batch of gas?
i did also forget to mention that this isnt his daily driver, so it does sit often....
also it comes from the drivers side in the engine bay somewhere....
he wants to bring it to the mechanic, but he'd like to have and idea on what it might be first, just in case it doesnt make the noise when hes with the mechanic
i did also forget to mention that this isnt his daily driver, so it does sit often....
also it comes from the drivers side in the engine bay somewhere....
he wants to bring it to the mechanic, but he'd like to have and idea on what it might be first, just in case it doesnt make the noise when hes with the mechanic
Last edited by stanger96; 05-11-2006 at 09:48 AM.
05-11-2006, 01:46 PM
#7
Teching In
Thread Starter
Join Date: Jan 2006
Location: Chevy land
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
well the thing is u can only hear it at WOT but only if you punch it from when your slowing down we have found, cuz when he tryed to recreate the noise for us it wouldnt do it during regular accel. only if you were slowing down to almost a stop then punched it ud hear it right around 5k
Trending Topics
05-13-2006, 05:08 PM
#13
Teching In
Join Date: Mar 2004
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
I don't think it would be the optispark, but you never know, anything can happen with them. It sounds to me more like a mild exhaust leak that is muffled by the other noises of the car until you're WOT. The air fitting on the driver's side manifold of my formula came loose and did the same thing. It was completely off the manifold and I could barely hear it at idle if I opened the hood, but at WOT it sounded like the car was going to fall apart. It could also be bearing or spark knock. How many miles are on the car and what's the oil pressure like. I had one opti cause spark knock, but it was nearly all the time, the car was overheating and generally didn't run well. All the other opti failures I've had were just a high rpm miss that gradually grew worse, then a couple of weeks later the car would just start dying. A lean condition could also cause spark knock, maybe the fuel pump isn't supplying enough fuel at wot/high rpm. Anyways my bet is on an exhaust leak somewhere.
05-14-2006, 10:53 AM
#14
Teching In
Thread Starter
Join Date: Jan 2006
Location: Chevy land
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
cool thanks
not to sure what the oil pressure is like but he has 90+k on the motor....if the air fitting on the header was just loose would it only make the noise sometimes then ?
not to sure what the oil pressure is like but he has 90+k on the motor....if the air fitting on the header was just loose would it only make the noise sometimes then ?
05-14-2006, 11:28 AM
#15
Teching In
Join Date: Mar 2004
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
No, it would make noise all the time. Whether or not it would be loud enough to hear over the car running all the time is a different story. I have no cat and a flowmaster only and I couldn't hear mine except at WOT.