Rattle/Knock when near-stall

[hozouria]

Hey guys,

Before anyone jumps the gun, I know it can be annoying when people post questions about the same stuff that's been answered a hundred times before. I tried looking online and through this forum to find a match to my issue, and while I found some that were close, I don't think they answered it to the extent needed. If anyone knows a post that has a solid review of the issue, could you please send me the link to that?? I would really appreciate it.

Anyways, I've owned the car for a couple months, and have noticed (among a few other things) some sounds which are not normal to me. I'm coming from a WRX so while I'm used to cars just making weird noises all the time, I get paranoid when it's a new sound to the usual cacophony I experience. When setting off, sometimes the car doesn't deliver the same amount of throttle as I want it to. Like I step on the gas to set off but it's not building revs at that particular throttle position like usual. Simultaneously I'm releasing the clutch to, you know, set off in first. But it seems that when this is happening at ultra low revs, the car does the typical slight shudder or what have you when it's about to stall. However instead of just shuddering, sometimes I get this knocking/rattle sound from the engine. Sounds like an old tractor.There's no other engine noise noticeable, and it's really low on power (which I know is obvious bc it's just about to stall out). I'm not horrible at driving stick and this does not happen every time I let the revs drop too much. That's why it's a little worrisome to me - instead of just shuddering until you bring it up to an appropriate rev range, once in a while it makes that sound. Maybe I should just start the car off at higher revs, but I don't see why I can't set it off at where the needle sits when at neutral. Provided you're giving it enough gas and letting off the clutch appropriately, the car should just set off fine, and it does 99% of the time. But this sound is just unnatural. It does not sound like typical knock, but instead is very loud and clunky like an old diesel tractor. I don't mean to ramble at this point, but has anyone else experienced anything like this?

I tried to bring it in to the dealership and have it diagnosed, but they turned me away because we couldn't replicate it. And it's not like I want to go driving and constantly try to near-stall my car until it happens again.

So, does anyone have any idea? Thank you!

[Tcoat]

Think you answered your own question. These cars are meant to rev higher then normal. Sometimes you may simply not be giving enough gas and once in a while you are lugging it. Of course you can start from an idle (don't know why you would) but at 600/700 rpm you will need some pretty fancy clutch work.
Just give it at least a little gas every time and you should be fine.


Oh and if you keep lugging (if my theory is correct) you will eventually damage your engine.

[strat61caster]

Can confirm, engine sounds like an old nearly dead tractor when lugged.

32k miles and not a single significant issue.

[humfrz]

Like said above, just don't "lug" the engine.

It's a bit light on torque and has a relatively light flywheel ...... so, make the clutch earn it's keep.....


humfrz

[Tcoat]

Lugged my on the way home from the dealer as not used to the clutch yet. The string of cuss words that came out of me made sailors blush for miles!

[Tromatic]

You should be able to set off in third gear from idle, just practice a lot. The noise will go away once you have completed the engine and drivetrain "bend-in" process. Although "maybe I should just start the car off at higher revs" sounds like a brilliant idea.

[Veloist]

Is this only happen when taking off in first?

I remember my 2013 at the near-stall point really shakes, compared to other manuals I have driven (Yaris, Corolla, MR2). However I don't remember any knocking. I will say that it is a loud and strong vibration. Taking off at 1000 rpm would elicit this vibration until gas is added.

You might have to try it out when the engine is cold vs. warmed up. Also, providing and audio clip or video clip will help because then other owners would really be able to tell you if it sounds normal or not.

[synchromesh]

I've got a bad habit of rolling into intersections minimizing the display of my ugly brake-lights. I think some people get pissed but the last few months I've noticed the side mirrors and rear window noticeably moves and shakes on some CD tracks with the wimpy stock stereo so a lot of times people give me way more space than I need.


Regardless, one time rolling slowly up a steep hill into an intersection, the car was at tip-toe speed but when I pressed the gas I heard a loud click even as it was in first. Freaked the hell out of me but there was no check engine light. All my other cars I've owned, second gear is ok at walking speed. Not this car.

[chaoskaze]

I feel the car lugs for anything below 1.5k rpm stock (on gas), however the car behave alot smoother after I got a dropin air filter.

[Tromatic]

OP answered his own questions in the OP.

[PatSciFRS]

It almost sounds like a bad engine mount but I am sure that the mechanics at the dealership that you brought it to already checked these out. Another possibility is that the exhaust pipe running under the car or a part attached to it may be very close to some other part of the car body. In any case what you describe does not sound normal. Look around to see if anything can knock against each other when the engine shakes from improper gear engagement. I must admit that I do not have this problem because I drive the AT but I have driven many cars with MT before. Good luck in finding and solving the problem.