Ok, first things first. I have a 2005 WRX Sedan running on only a TurboXS TBE and a Cobb AP Stg.2 OTS tune installed about 20k miles ago, nothing else. I run 93 octane always, as was required by the tune. The map was installed at around 55k miles and am now at 75k miles. I run Rotella T6 oil and a Bosch filter. I have no CEL's and overall, the car runs wonderfully. Haven't noticed any change in power or gas mileage since noticing this noise. This noise seemed to have come out of the blue. I've not tried anything to fix it yet as its not really been causing any mechanical issues. Also, I have an AP, but haven't datalogged yet due to A) not knowing how, and B) just been busy and the noise keeps going away for two weeks at a time.Provide as much info as you can in you posts
*All performance mods (80-90% of the problems are due to improper modding/mods)
*octane of gasoline being used
*Year/model of vehicle/miles on vehicle
*When the problem started (when I changed a part vs out of the blue)
*If you have tried to fix the problem list what you have done
*If you have the ability to datalog definately run a log.
Some background, I'm a mechanical engineer and have worked on my own cars my whole life. While I'm not claiming to be a full blown mechanic by any means, I'm only trying to say I can follow general terminology and conversation in this field.
Now, for the bad, err, annoying. I've heard this ticking noise perhaps half a dozen times over the past two months. It only occurs at idle (stop lights or signs) and only lasts for a few seconds, max. In fact, its so sporadic, I can't ever get the phone out in time to get a good recording of the noise to post.
At first, I feared the terrifying rod knock or spun bearing, but after having a still operational engine for two additional months, I doubt its this. Besides that, those issues seem to be very obvious and quickly accelerating, and this problem definitely hasn't shown either of those characteristics.
Secondly, I thought it may just be piston slap? But after reading more, this hasn't occur at start-up yet and it really only started happening in the hot weather, opposite to what I've read about piston slap, which seems to happen mostly during cold starts and on aftermarket piston'ed engines, though again, I'm not sure on the accuracy of all that...
Finally, at this point, I'm thinking maybe my timing belt tensioner? Not sure on any of this though, that's why I'm looking for your advice. The only thing that made me suspect the tensioner were the two videos below, found in this NASIOC thread:
YouTube - ‪Dead timing belt tensioner. Impreza WRX‬‏
YouTube - ‪New timing belt tensioner. Impreza WRX‬‏
Just to clarify, my problem/noise is NOWHERE NEAR this persistent. My only guess is its leading to this problem, but nowhere near shot yet. But what do I know...
Also to clarify, this does not resemble rod knock or a spun bearing as heard in countless YouTube videos.
I've dug up this DIY from this forum and feel pretty confident in my ability to complete this if needed: Timing Belt and Water Pump Replacement by section9.
Any help is much appreciated and please refrain from hating if at all possible.