I have a 2010 5MT and sometimes when I shift 1 to 2 or 2 to 3 when I hit the gas I get a pop or bang that sounds like it comes down near the front drivers side tire, it's pretty loud too. Best I can explain is if a rock had kicked up and hit the bottom of the car. Usually when I drive I hit the gas to the floor, not usually in 1st, but the upper gears. I'm not revving to redline either. I do have the HPS air intake, and thought maybe it was coming from there, but it sounds down in the nose of the car more. Has anyone had this?

 

Check out your driveline, joints, the tranny is over there. even your control arms at their bushings n such. There's a lot less force exerted by the upper gears, more about spinning fast.

 

Think your Gearbox / Engine mountings are shot

 

Also forgot to add that it happens when I rev match on a downshift. Clutch in, blip the throttle, and when I hit the throttle, there is no load on the engine and it's happened then too. I thought maybe it had something to do with my air intake. Not sure if it would be the trans or mounts if there was no load on it?

 

Now we're saying it's happening when the clutch is 100% fully disengaged from the flywheel?
You can check the slave cylinder up front in the nose
​. I dont know how or why that would fail, but it's in the area and.. you know. it's got the shift fork right there, engages the throw out bearing. Maybe your issue is in there, but that whole mess requires dropping the transmission, hoss.
"The most common sign of a bad throw-out bearing is when you hear various noises when you depress the clutch pedal. ... The noise will sound like it's coming from the transmission area. The sound will be most noticeable with the clutch pedal fully depressed and go away when you take your foot off the pedal." copied from allinoneauto via google search.
​​​​​​That's not all inclusive of every symptom that you can experience.

Here's a brief descrip "The "throw-out bearing" is the heart of clutch operation. When the clutch pedal is depressed, the throw-out bearing moves toward the flywheel, pushing in the pressure plate's release fingers and moving the pressure plate fingers or levers against pressure plate spring force." from edmunds.
"Broken Fingers or Spring – if one of more of the clutch pressure plate fingers that protrude out from the centre of the clutch plate are broken or bent then the clutch will not operate correctly, and maybe become difficult to engage your gears." some f*ckin site.

Think you may be past due for a clutch? Cuz that'd be the most likely cause. I can also say that by 80k miles I replaced mine. The clutch still had life but the springs had been permanantly depressed in no small part due to my learnin how to drive a manual.

The upper clutch is the exedy I put in. I dont have a youtube, so cant upload the video. But my old clutch's springs shook in their holes. Wouldnt surprise me if I let it go farther, if one popped out at least partly.

 

That's a great write up and thanks! I'm not quite sure if that's it. If I had to guess, my clutch is still very good. It's a 2010 and has 65k on it. I got it 3 years ago with 36k, so not sure how the original owner drove it. It had detailed service records and was taken care of and serviced. I also have a 2005 Acura TL 6MT with 145K and the original clutch. I usually don't beat on my cars too bad, but that doesn't mean parts can't wear. What I need to do is turn the mic on my dashcam and next time it does it, I'll post the video. Sounds like a large rock whacks the front end or a gunshot when it happens.

 

Sounds would be useful, and if you're in for a penny and live near decent roads, I know a lot of the tacoma guys hook up go pros under their cars when they have drivetrain issues. It's unlikely that, based on your description and mileage, there are any issues.. well, at all really, but none at or after the tranny (unless you count inside of the bell housing as tranny).
In trusting that you're an experienced driver, man, if the oil has been maintained.. Would you wanna put the front end in the air and have someone (or you) watch it while replicating the fault. Kinda dangerous even if precautions are taken. The engine is running normally, no?
​​​​​​
In the past when I've been unable to recognize a fault, I'd take it to a shop for an inspection then do the repair they recommend myself with parts sourced from, typically, rockauto.

 

Problem trying to replicate it is it happens every now and then. I try to figure out if it's when it's cold, hot driving hard or not. There's really no thing I can do that will make it happen. I know the car was maintained before I got it and I'm up to date with everything, just changed the trans fluid last oil change. As far as driving stick, I learned at 13 and I'm now 43 so have a few years experience. If I can get video/audio of it I'll post

 

Hahah, right on. That rules out potential for inspection. We'll see what other folks have to offer.
If I didn't say already in this thread, having thoroughly experienced only one other clutch (wet) thoroughly, I dislike ours. It feels too aggressive to me, so I tweaked it a bit. Master cylinder from an 01 civic (no delay valve), short shifter, pedal lowered all the way down and bel ray brake fluid, knock-off chingaderas that reduces crankcase pressure.
coming from a honda dual sport, having skated goofy, that delay valve just wrecked my already awful left leg articulation. Before I did my adjustments, my family and friends drove it too, and none of them could make a smooth engagement save my father, who compensated by revving the heck out of it. It's my understanding that any roughness (including rapid acceleration) at the wheels is transferred directly to those clutch springs. It's really the only part of the system that's designed/purposed to actually absorb rotational resistance.

Since it's what I've experienced i'm sure it's clouding my judgement a bit. if there's any other nuances about the ride (always compared to a just rolled of the lot new car) be sure to post it up! These things are fun brain teasers.

 

Your Fit is about identical to mine...2010 m/t with hps intake.

I have 230K miles on the original clutch and have never heard any sound like that from it.
How about your cv joints? Have you crawled under and tested for any looseness?

 

Sorry to resurrect such an old thread but I have this exact same problem, very loud backfire from intake when blipping throttle to downshift to 2nd, did you ever figure it out? I've already tried plugs & coils but it still happens intermittently

 

No I have not. Happens every now and then. I do have the hps air intake on my car. Can't remember if it did it before that with the stock intake on it.

 

I have the takeda CAI and only ever noticed it after the intake as well

 

Just an update, my spark plugs were loose (torqued @ 13ft lbs from hondas old torque specs) - re torqued them @ 20ft lbs which is what honda changed the specs to and now the car feels much better in the lower rpm, i'm gonna see if this fixes the intake backfire

 

That's a great way to describe it, an intake backfire. That's exactly how it sounds I guess.

 

Just an update, still get the intermittent intake backfire when blipping throttle on rev match down shifts, so re-torque of the plugs didn't work. Cleaned the MAF & MAP sensors but still happens. Ran 91 octane for 2 tanks, but still happens. Doing a google search I find some honda bikes that have the same issue when down shifting due to the ECU running super lean on decel then you suddenly blip the throttle causing detonation. Thinking of grabbing an obd2 bluetooth scanner to datalog whats happening when the backfire happens

Things I'm thinking of trying next:
- Denso IK22 plugs, as apparently the stock NGK plugs sit deep in the cylinder causing hot spots & motor to run lean, the IK22 sits higher up
- valve adjustment

 

Another update, haven't had the backfire happen since Oct, only difference is I've been running 91 octane since