Upon acceleration there is what seems to be some piston slap, or something inside the crankcase. It's only when engine has load (so not in neutral). It's not regular, but i can replicate the issue easily.

My hope is that it's not a supercharger problem, and since it only occurs under load and I just hit 100k miles, i'm worried.

Thanks in advance.

 

possibly timing chain/ guide problem. when load is applied one side gets real tight while the other side is loose and slaps up against the guide.

is it a constant slap or just when you decide to give it a little gas?

 

What gas are using?

 

I believe it's when mainly I accelerate. I'm using 91 octane, so i don't know why it'd be slapping. It's definitely not constant either. Sometimes I'll accelerate hard and I'll hear it once, and sometimes it's a bunch of pops. The timing chain would be under tension regardless of if i'm moving or not, right?

 

no, the T-chain would not be under tension if the tensioner or the guides are crap. the chain is quite slack with out it so under load it will tighten on one side and be very lose on the other. and at a constant speed it will kinda even out until you give it more gas.


other than that does it pop when you turn at all? CV joints make noise if they are bad, even in a straight line.

 

are you going to be at car club i can check the noise for you then.

 

Sounds like your car is knocking under load.
Go find some race gas, Fill the tank with that and see if it will keep doing it.
If it stops you need to find out why its knocking.
a chain tensioner would be constant sound.
And i have seen a tensioner with the guide material completely gone and the car still ran fine.

 

his car runs fine, he just has a weird noise when ever he trys to accelerate. if it was knocking it would feel different, sound different too. and just because the guides are gone doesn't mean the chain was still under some tesnion. im not saying all tension in his chain is gone but it is possible.

 

Most people cant feel knock or know what it actually sounds like.
its fine you can disregard my advice. its free anyway.
its not like I work on these or something.

 

Ted, when do you have some free time tommorrow? we can go for a quick drive and see whats up we can take a vid too, to show the sound if need be.

i see your car at aschool in the morning my first class gets out at 12 so dont know if you have class then or not

 

Check spark first = bad coil pack, coil pack connectors corroded, check wires lastly pull plugs.

Fuel = run some Isopropyl gas line additive to the tank, maybe you pumped a boat load of water at last fill up. Do not use methanol gas line additive as since it will not blend with water and separates it will NOT remove water from your tank.

 

I replaced my spark plugs 3000 miles ago and changed to NGK iridiums. I accidentally put in 87 octane that same day and it made the knock. I actually put some octane booster in there too to try and even it out. Since then it's been 93 octane premium.

Raven, there is some minor corrosion on the 3rd Coil Pack Connector, as is usual for these models.

Gabe, I'm free all day tomorrow, and live on campus, so send me a text. I'll PM you.

 

My bet is that the fuel pressure regulator hose is off and its knocking under load.

 

Hi Guys, same deal here. Changed the oil on the weekend with mobil 1 5w30, put in a 15 pulley yesterday and the clacking of death ensued. At about 2.5k RPM i get super loud clacking. going to check the oil again and see if that needs a topup.

 

Vox, It sounds like you have a different problem than mine.

 

Vox, I think you need to check your work on that pulley -- ie: did you seat it evenly and properly.

Unless you are really down on oil it wouldn't likely be the issue. Did you use the right sized belt? Did you check your tensioner?

 

Typical with OEM coil packs and it will cause these issues under load in that cylinder. Use the back of a sponge's green scrounge to remove the corrosion and tarnish. Just don't use anything too abrasive, an old sink sponge will do it. Also check that wire end for corrosion as well.

I eventually went with an NGK coil pack and NGK wires. Had to get new bolt hardware as old ones cant be used. ( *** New bolts must be same length.... )

 

ted it ever come back?

 

No will never come back.

The connectors on the NGK coil pack are made of brass instead of the stainless steel ones on the OEM coil pack....

 

Update on this.. apparently i threw a rod bearing :(
(thread here https://www.northamericanmotoring.co...day-today.html)

 

So, a quick update. Upon downshifting from 3rd to 2nd, I'm hearing it. Also, I took a look at the coil pack today to find that #4 was very tarnished/corroded. It was solid brown in color. I took the back of a sponge and tried to rub it off, and I managed to smooth it out, but it's still a bit discolored. I'm still hearing the noise on downshift, but not so much on hard acceleration.

Seafoamed the car today, put some in the crank case, vacume hose, and gas. It had no crazy white smoke (like i've seen on youtube), but a bit of black smoke when I really revved it up. I let the car sit with the engine for 5 min like the bottle said. I think someone said it should be closer to 30 min...maybe that's why I didn't get the massive smoke?

 

yea when you suck it up, your supposed to kill the engine when your done and let it sit for 25min then start it up let it run for 10 then go for a drive and fumigate the neighborhood. then when your done with that you can add it too the oil and or gas.

EDIT: YOU ALSO HAVE TO CHANGE YOUR OIL WITH IN A WEEK IF YOU PUT IT IN THE OIL!!!...... I always seafoam like a few days before i change my oil, so i dont have to worry about it.

 

Yep, didn't let it sit long enough :/

 

If the terminals on the coil pack are still corroded, spray some STP carb spray cleaner on a rag and rub them down, or use a brass brush to clean them up. You can help prevent future corrosion by purchasing a small pack of the spark plug grease at the Autozone or Advance counter.

Usually, if your timing chain tensioner is going bad, you will hear it at idle. Even if you put your plugs in 3,000 miles ago, check them and make sure there is no fouling. The one time you used 87 Octane could have been enough to do that. The knock sensor should kick in and retard your timing to prevent the knocking sound you hear. Check the plug gaps. A quick Internet search shows the NGK Iridiums should be .035".

If the issue has not gone away, put back in your old plugs (if you saved them), or see if someone you know has another set laying around. In rare cases, I've seen others post they had an issue with a particular brand/type plug. Even though we all drive MINIs, each can have its own personality.