well, about 2 weeks ago i put the stock air box on the ld9 s/c to save gas mileage for winter and now the motors knocking, sputtering and has no power at all. When i let the car idle you can hear a knock/tap coming from the valve cover area so thats either a wrist pin (again), valve, lifter or timing chain problem i'd say. Also when im going down the road cruising it will sputter VERY bad like a wrx car when i hit the gas pedal and if i mash the gas it will do this or it will pick up and go but you can almost hear things going through the motor like metal pieces or something.

The car does not seem to be smoking when it does this or smoking at idle either. I last had a oil change about 200 miles ago and oil is at perfect level and the injectors should be clean because i put in some cleaner today after this all happened. Anyone have ANY ideas because if it needs a rebuild AGAIN i will be parting out all my performance LD9 parts.

Sorry to hear that.. but i have no clue what could be wrong. Maybe someone could chime in n help!

Did you check to make sure there wasnt anything in the air box of piping when you put it back on? If there was then its in your motor, causing that sound.

of course i did, i blew it out with an air compressor and everything before putting it in, in 2 weeks i think it would have sucked it up the first long drive i did if anything was in there. Oh well, parting out time.

did it happen as soon as u switched the air box? did you try putting the aftermarket one back on? thats really strange that, that would be the cause... I wonder if it was just coincidence. Either that or it reduced your airflow so much that being boosted, it through your AFR way off, and if you get too rich or too lean you'll get knock, and maybe you got alot of knock and it messed something up or could be ok once the AFR is right again? I think would be very drastic but i dont know...? just a thought..

Maybee something in your coil housing has cracked or messed up and you have all sorts of arcing going on in there... it's a long shot... but I'de check it out...

There's the posibility that your timing chain coulda jumped a tooth..... or you have a broken valve spring or retainer.

If the bleed off valve on the supercharge is malfunctioning... it might cause some problems like that (exept for the ticking)

When was the last time you checked the oil in the supercharger?

Just a few things off the top of my head.

took plugs out today, all of them are gapped fine, they are black and brown and the tops of the pistons from looking down the plug holes is black, any ideas? still idles like a wrx with a slight knock

The black would be carbon build up.. happens more often when the car is running rich.

As far as the STI sound you're hearing.. Both my BF's SS/SC and my friend's SS/SC started to have that STI sound when both of them blew their ring lands. Although my friend's got worse and that STI sound was more prominent than in our SS but his motor ended up blowing completely. But I cant recall what exactly happened.

Do you have an AFR gauge? What do your fuel trims look like?

im running a aem wideband, at idle it's in the low 12's so rich but you wouldn't think it would blow my ringlands, oh well rebuild part 2 time.

Let us know if you find out what happened

Good luck!

blown ring lands cause the WRX sound because they smash plugs closed and you lose that cylinder (read: no spark).

I ran my car with a chunk of my piston missing for over a month and it ran fine once I put new plugs in it (so long as it still holds compression, which it did)

check your ignition stuff, your mechanical timing (timing chain)


did you switch what kind of fuel you're using?

alright heres the latest:

i changed the whole IDI cover and assembly from a car i know starts and runs perfect.

Start it up it's choppy as hell, after about 2 mins of that it smooths out and idles fine. I give the car a rev or 2 and its fine.

I hold the gas to 3k for about 5 second and sit starts sputtering really bad once again and died when the rev came back down and was hard as hell to crank over after i tried to re-start it. The only codes it's throwing are p141 cause of my o2 sensor which i've had thrown for about 2 months but just haven't fixed it and a random misfire 300 code. I'm at lost for ideas now.

Any ideas?





Edited 3 time(s). Last edited Friday, December 07, 2007 6:58 AM

Have you checked your o2 sensor?

Mine ran like @!#$ and did that exact same thing when i had a bad 02 sensor plugged in. I unplugged it and now it runs perfect.

so unplugg the rear 02 sensor and start it unplugged?

For me it was the first sensor, the car doesn't run off the second. Try unplugging the main o2, stock its off the header. As long as your tune is right on you should be fine running it w/out the o2. Once you go into PE you don't use the sensor anyways. And for me I have HPT set to put me into PE at 20 or 30% throttle anyways..

What mine did was start up ok, a lil rough but it evened out, but as soon as it got into closed loop and started trying to run off the sensor it was ok until i revved it at all, then it started spitting out tons of fuel, idling horrible, almost dying etc... i unplugged the sensor, started it up, let it run, revved it a lil, everything was perfect...

i have a slight tune and it's not tuned to turn off that sensor and i don't have HPT i had a friend flash it ro run alittle better about a year ago.

i would suggest getting a new sensor. not only because it sounds like the problem i was having but also because u are in fact throwing o2 sensor code.

I would probably try starting it w/out the sensor plugged in (the wiring clip, u can leave ur sensor in the mani/dp) You have a w/b so you can still monitor the AFRs, and it safe to ATLEAST idle it w/out the sensor because thats how your car runs when u start it up anyways. Just see if it effects anything. if it still runs like @!#$ you can probably cancel that out i suppose...

timing chain just snapped, car is done now. Wont turn over. Parting out, see North East Region for sale threads.