knocking sound?

THAWA · Post by **THAWA** » Tue Aug 24, 2004 4:04 am

I didn't know where to put this, it could be a body thing, or it could be a trans thing, or it could be suspension, or even engine unfortunately. I noticed today that when travelling real slow, like 5-10 mph, whenever I brake or accellerate i get this knock sound, and kind of a tap I can feel (dunno if it's through the pedal or the floor I'm feeling it, but I definately do feel it. I did notice the past weekend a fairly strong burning smell. I can't pinpoint what it smells like though. It sort of smells like brake pads, but then again it smells like oil too. Also with the vents on I can see a little bit of smoke coming in the car (which is horrible). I'm almost leaning on this being exhaust related, since I don't have the middle bracket that connects the exhaust to the transmission, but I dont know what the smell is coming from. What should I check?

vrg3 · Post by **vrg3** » Tue Aug 24, 2004 4:34 am

THAWA wrote:I noticed today that when travelling real slow, like 5-10 mph, whenever I brake or accellerate i get this knock sound, and kind of a tap I can feel (dunno if it's through the pedal or the floor I'm feeling it, but I definately do feel it.

This almost exactly describes the symptoms I noticed when my driver side strut top nut was loose.

THAWA · Post by **THAWA** » Tue Aug 24, 2004 4:38 am

that sounds quite probably, but I never would've thought of it. It also might explain why the car is so jerky when going slow.

evolutionmovement · Post by **evolutionmovement** » Tue Aug 24, 2004 4:47 am

Or a broken strut.

Steve

entirelyturbo · Post by **entirelyturbo** » Tue Aug 24, 2004 4:51 am

You said it's in the middle of the car, I say it's that missing exhaust bracket...

THAWA · Post by **THAWA** » Fri Aug 27, 2004 4:54 am

Now that I hear it more it sounds like misfire/backfire I'm going to change the plugs tomorrow or sat and see if that helps.

BAC5.2 · Post by **BAC5.2** » Fri Aug 27, 2004 7:00 am

I don't have that bracket, and no negative effects.

One thing. My car is jerky as HELL when going on-off-throttle. I attribute it to the AWD and Group N engine/tranny mounts, flywheel, and grabby clutch.

THAWA · Post by **THAWA** » Fri Aug 27, 2004 7:33 am

yeah about the jerky thing, I'm thinkin it's just the design of the powertrain layout. drove a couple wrx's today and they were only slightly less jerky

BAC5.2 · Post by **BAC5.2** » Fri Aug 27, 2004 8:20 am

Yep. My jerkiness went away a bit with the mounts (less movement on the chassis). So instead of a jerk off-throttle (the engine moving on the mounts), it jerks the whole car. Less of a jerk, but still a jerk.

It's an inherent attribute of most Subaru's. The STi I auto-x'd didn't seem to do it AS bad.

scottzg · Post by **scottzg** » Fri Aug 27, 2004 8:50 am

I'm pretty sure the off throttle jerk is caused by the efi not being able to predict how much fuel to use when the throttle snaps shut. I think this is one of the advantages of carbeurated setups. Our heavy drivetrains prolly just exacerbate the problem. I have a loose strut top nut right now, but no burning smells, and its only over bumps.

BAC5.2 · Post by **BAC5.2** » Fri Aug 27, 2004 2:24 pm

Odd, no other EFI car I've driven has exerted the same jerky-motion.

Makes me feel like a n00b in traffic when I am just jerking along. My clutch doesn't enjoy going slow.

THAWA · Post by **THAWA** » Fri Aug 27, 2004 3:55 pm

every car i've driven has jerked, some more than others.

scottzg · Post by **scottzg** » Sat Aug 28, 2004 5:20 am

Like most things, ive learned how do drive around it. I've noticed it in my folks' camry and pickup, and my vacuum powered fi on my bmw didnt do it.

georryan · Post by **georryan** » Sat Aug 28, 2004 7:14 am

I can drive slow and pretty smooth. But I've learned how to adjust the slightest of pressure on my gas pedal to get it to go. I've litterally coasted down to like 2 miles an hour with the clutch fully out and gotten back up to speed after a bit....but it isn't easy to be smooth. Takes some seriously light touches to the gas pedal.

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knocking sound?

knocking sound?

Re: knocking sound?