What's this knocking in my MX3?

[Sookys]

So my MX3 will make a knocking noise, only when I am giving it gas and obviously am in gear driving it. The more gas I give the louder and harder this knocking seems to happen, if you let off the gas completely & cruise, it goes away until you give it some gas again. It feels like metal clanking on metal, it's the same knocking as when your front left or right axle goes and when you go around corner's it knocks... same type deal. Does not increase or decrease knocking when going around corners, though. Anybody know what's wrong? I read something about maybe a pulley knocking against the back of the timing belt case, didn't know if that's true or not.

Thanks for the help

[Savin]

Is it a continuous knocking or just one single knock every time you give it gas? If its just a single knock, it could be a bad mount somewhere. As for a continuous knock, it could be a rod knock, but I highly doubt that is the case unless your car has been very poorly treated.

[OldMan]

Does this knocking sound happen if the car is sitting in neutral and you rev the engine. By doing this you will have eliminated the drive train as being responsible. If the knocking occurs when the car is in neutral sitting still then you know that it is in the engine. From there you will have to look about to find out if it is external, pulleys or accessories. If the noise is coming from within the engine itself, then you could very well be dealing with rods that are worn or even damaged pistons. This would indicate as Savin mentioned above that you have an engine that has been abused. Your only choices then would be whether to rebuild what you have or replace it with another engine. Either way is going to be expensive.

If you are mechanically inclined this is something you can do yourself, which will save you some dollars. If you opt to install a different engine, it would be very wise to go in and check everything over, replacing anything that looks to be questionable. Definately the timing belt and water pump while it is out of the car, much easier then. I have seen people fail to do this and after the replacement engine is installed, find out that they have to go back in and make repairs.

Maybe you will be lucky and find that it is not in the engine. It is going to take some careful diagnosing to find out what the problem is. As you check things out post and let us know what you are finding and I am sure someone here can assist you. Good Luck!

OldMan

[xSocialx]

Might just be a bad cyld. But it could also just be a seized barring in the alternater, I had that happen to me once I thought it was an engine knock

[Sookys]

I will accurately attempt to explain every detail of said knocking for you, thanks for replying btw. The ONLY time the knocking occurs, is when it is in gear and I am driving. If I am in neutral and I rev the engine, nothing. The knocking becomes faster as I accelerate my car. The knocking occurs faster as I gain more speed, it is not affected by my RPM's, and is not affected by going around corners. My brother said it most likely has something to do with the transmission... Hope that's enough, please let me know. Thank you so much for your help, it truly is invaluable. Mechanics cannot be trusted.

[hgallegos915]

audio clip please

[RX8SE3P]

Well it's not the engine if it won't happen in neutral. It sounds like your drivetrain/gearbox. That's where I'd be looking.

Does it happen when you're driving and slip it into neutral whilst driving or ONLY when in gear and driving?
How do your shifts feel?
Any gears hard to get?
Does this happen in ALL gears?

[xSocialx]

Sounds like an internal transmission problem

[hgallegos915]

no.. i dont think itds a teansmissoon problem.. if the tranny shifts well.. and has clean fluid.. its ok..


I think its either a cv joint, or a shaft.


Dont replace your transmission over a slight knocking sound.


Its probably that shaft bracket. or bearings.

[Ryan]

You have a rock in your tire.

That would be my #1 thought.

[Sookys]

In response to RX8SE3P:

It doesn't really seem to be affected by gears because when I let off the gas it knocks hard, and when I boot it, it knocks hard. It seems the only way for it to go away, or to become not as hard of a knocking, is to give it a slight bit of gas, so I am accelerating slowly; and for some weird reason it almost entirely + completely goes away from what I can feel + hear while driving if I apply the brakes, the harder I apply the brakes, the more it goes away. When I am driving and slip it into neutral thats when I let off the gas obviously which is when the knocking is hardest (along with giving it full gas while driving). Doesn't happen while standing still. I can hear it starting to grind slowly, oh so slowly like its a notch on the axle hitting something (just what it sounds equivalent too), and the faster the car goes, the more rapidly it knocks. It seems what makes the knocking more vibrant (i.e what makes the pounding at my feet come through harder) is opening up the throttle, but what makes the noise loudest is when I let off the gas entirely. Strange, I know. Shifting into 5th while giving it hard, I have to slow down my shift *just* a nudge or it will grind, and also downshifting from 2nd to 1st requires me to be going less than 15 km/h or it just wont shift, Idk if that is due to the fact that mx3's are very short geared or what. Shifts feel smooth though in all other gears, car pulls awesome.

[Sookys]

And I just replaced one of the CJ joints, however even if it was it would occur most while going around a corner wouldn't it? Thats what I experienced when it went, and from memory it would drive in a straight line without making too much noise, this problem is different.

[SuperK]

Hydraulic tensioner?

Correct me if i'm wrong, the K8 has a hydraulic tensioner like the KL series. It sounds exactly like a knock.

[Sookys]

That's what I've been hearing... would that tensioner knocking increase in knocking when the car itself speeds up or the engine?

[SuperK]

well, naturally. More pressure on the belt, more pressure on the tensioner. If it's weak, it'll just start knocking.