Very slightly clutch pedal 'buzzing'
 

Alright, so my clutch pedal has been 'buzzing' for as long as I can remember (several thousand miles), and I've always noticed it, but I never thought anything of it... until now(dun, dun, dun -- started reading about this problem). Oh and I do mean buzzing not vibrating as far as I am concerned (as in it's a very, very slight buzz). More specifically, the 'buzz' only happens when I rest my foot on the clutch maybe half an inch. It doesn't vibrate at idle, only when I step on it, or if the car is at a high rpm, but even then it's very slight. However, as soon as the clutch actually begins to engage the buzzing goes away. Furthermore, I run my card quite hard (not abusing it, but hard). I take a lot of logs (will post the most recent one down below, and YES I KNOW THE FUEL PRESSURE, I AM GETTING HPFP INTERNALS THIS WEEK) and never show any signs of knock, which I'm fairly certain even the slightest bend in a rod would show.

Also, there is no ticking from the engine, no metal on metal grinding, no knocking. It sounds perfectly normal, and also shifts perfectly normal. First I'm going to rattle off the mods that I have on my car, and then I'm going to provide a little bit of a situational problem that may be contributing to this.

Car statistics:
Year: 2012
Miles: 34,000
Warranty: lol (no-voided because, and I really do quote here, "car has been exposed to unreasonably cold temperatures and extremely adverse weather." Like what the actual fuck)

Mods:
CorkSport SRI with TIP, CorkSport short shift plate, CorkSport metal shifter bushings, CorkSport rear motor mount, running an ots stage 1 (Cobb AP) tune that I did a lot of work to myself--maf cal, improved AFR, blah blah blah. Oh and a forge BPV

Situational problem:
Alright, so about 8,000 miles ago I got the trans fluid changed because why not. The place where I got it changed (I am up at university with no tools etc so I have to go to shops to get this work done) didn't have the proper transmission fluid, which is 75-80, so they convinced me that 75-90 would be fine. It took a lot of pleading to get me to agree to it, and now I realize they were probably taking advantage of me because apparently 75-80 trans fluid is really rare. Problem number 2: It gets really cold here, and I do mean cold. Highs in the single digits and lows well into the double digit negatives. So what I'm thinking is that because the oil is too thick and it gets mind numbingly cold here, that the trans fluid could not properly lubricate the clutch and so it has worn unevenly causing a slight buzzing when RESTING on the pedal, which does go away as soon as the master cylinder engages.

What I am thinking is that improper clutch wear could be causing buzzing feedback in the lines, and thus buzzing the clutch ever so slightly until pressure is put into the system and the master cylinder engages. The brake and gas do not vibrate aside from regular engine vibration. Conclusion: I think it is most likely nothing rather than something, but I wanna hear what you guys think. Ask me questions, keep it civil for the sake of all of us.

Alright so I took a video of the engine idle, and as far as I ca tell, it sounds normal besides the fact that the timing belt seems a little bit off(?). However, what is not normal is that the bolts holding the inter cooler shroud to the inter cooler snapped because it's so damn cold out. Sooooo need a fix for that now

The ticking you talk about in the first clip is your HPFP -- completely normal.

Running your car without the intercooler shroud isn't going to cause any damage. You'll want to drill out those broken bits at some point though and replace the M6x1.00 bolts.


I'm not sure what to say about your buzzing clutch... Where is the sound emanating from exactly? Maybe take a video of it?

Also, you state that it only happens when you "rest your foot on the clutch".
Hopefully this was a poor choice of words or i'm interpreting this wrong, but you shouldn't be "resting" your foot on the clutch.

http://i59.tinypic.com/2r7yijr.jpg

http://i60.tinypic.com/2il2f9.jpg

http://i58.tinypic.com/122nfcg.jpg


I noticed you posted this in another thread while evaluating someone's log (I highlighted the more relevant parts):

...but in your log, you're going WOT from 1700rpm to 6750rpm (possibly higher -- dunno -- log cuts off with you at 6750). If you're aware that it's not good for the car, why are you doing it?

I'd change your transmission fluid, see if it helps. And maybe this time use the correct fluid to avoid damaging your transmission.

Yes, it was just a poor choice of words. I do not 'rest' my foot on the clutch. The only time I clutch in is when I go to shift. There is no 'buzzing' sound, just a 'buzzing' feeling, which like I said, goes away as soon as the master cylinder engages. At this point is most likely just engine vibration resonating through the car because when the master cylinder is not engaged the clutch pedal is "lose" so to speak, so it has some room to buzz around.


This log is a week or two old, and I just started doing a lot of research these past few days, and I have stopped pegging it below 3k RPM, and I'm also lowering my WGDC below 3K RPM to eliminate almost all turbo spool before 3k RPM



Also, as far as the knock goes I do believe anything below 1 degree is nothing to raise alarm(?). Pretty sure that when it's low like that, especially when you first put your foot down, it's either the engine trying to quickly maximize fuel efficiency before fuel trim goes into open loop, or just a very uneven, bumpy surface I could have been driving on. I could be wrong, but that's just what I've read.

Oh yeah, definitely getting the trans fluid changed this week, had to call around to FOUR Mazda dealers before I found one that had it in stock. The wrong trans fluid, especially since it's so cold, has been causing me a lot of problems: syncros in 5th gear not being lubricated correctly because not enough fluid can be pumped up there to lubricate 5th because it is too thick. Anyway, that's a different problem.

I was mostly being a smart-ass by pointing out the knock retard values and don't suspect it's any real cause for alarm. I will point out, though, that although the values were low they're there with some consistency. When I was looking at your log, I literally had KR values greater than 0 filling my screen, top-to-bottom (and then some). I suspect this is most likely the result from doing a WOT pull from such a low rpm range, though.

Yeah that's what I was thinking as well. So clutch buzzing appears to be normal for the most part. Now time to fix 5th gear :damnit1:

I wouldnt go WOT at such a low rpm. Asking for a bend a rod depending on what gear your in

Yeah I talked about how I'm not doing that anymore. This summer, once I finish my internship, I'm probably going to build my engine up to mostly eliminate the possibility of throwing a rod.

I just got myself a short block build and had no idea i had a bent rod until the motor was taken apart. I had no clutch vibration and no knock at all.

That's actually really interesting. The rod probably bent just as you were about to swap the motor. Usually once the rod bends (if it even gets a chance to bend, they usually just blow) you have a very short amount of time until it goes jihad on your block.

Getting a little bit off topic here, but just going to finish up with this:

as far as the engine build goes, I'm thinking about doing this:
-upgraded rods
-upgraded pistons
-new valve rods and valve springs
-maybe a bore, hone, and balance
-oh and since the engine will be apart may as well throw on a new water pump, timing belt, etc... generic maintenance stuff
Definitely going to do the first three because they should strengthen the engine at its weakest points, and also give my engine a much greater life. I don't plan on making more than 400-410 hp at the wheels, and almost every single engine failure on here appears to be from bent rods, and the occasional cracked piston head. I have actually yet to see an engine fail because the stock block was not adequate enough. Anyway, just thought I'd end on that note.

Sounds fun...good luck..

Timing CHAIN, VVT, etc... I could maybe understand having done.
But at 34k, I see no reason to replace your serpentine belt or water pump. They're both things you can inspect visually for failure over time and both are simple to swap out.