impreza STI PPP knocking

[scoobyPPP]

Hi guys, i was wandering if anyone could help me, i have a subaru impreza sti with ppp, recently ive noticed that every time I turn the engine off, i get a rattle noise coming from the engine. i don know if this is due to the cold weather or not, but if anyone has any advise it would be much appreciate.

[Syndrome]

Check the engine mounts are okay. If they are then I suspect it's a big end bearing failure and a rebuild is in order.

[scoobyPPP]

if it were the big end bearings wouldnt it make the rattle noise while driving or switching on the engine, this noise only happens sometimes when i switch the car off, cheers

[Syndrome]

scoobyPPP said:

if it were the big end bearings wouldnt it make the rattle noise while driving or switching on the engine, this noise only happens sometimes when i switch the car off, cheers

It sounds more like a cover or a mounting has come loose somewhere in the engine bay (I couldn't pinpoint it without hearing it first hand). You'll just have to stand peering into the engine bay with a torch whilst someone else switches off the engine I think.

[Smifffy]

The turbo/heatshield covers are always rotting and coming loose on Imprezas. God knows how many I've gone through. Check this is intact? (But NOT after driving obviously) :P

Does it sound like a bottom end knock or more tinny?

[cptsideways]

Bottom end or piston slap is the more common noise, though you'll get this from start up or under load. I'd say a heat shield is loose.

[Scooby P1]

Agree with Smiffy, Heatshields are obviously held together with selotape - I am yet to have an impreza where it doesn't rattle at around 3000rpm especially on the overun - makes it sound like an old quad bike!

Hammers and crow bars can sort it out though!

[scoobyPPP]

thanks for all the replies guys, took the car out today for a run and noticed there's defo no knocking when starting up or driving, the car seems to only make the knock sometimes when switihing it off. if i leave it to cool down long enough then I dont get anything no sounds at all by the looks of it, tried this today with the bonnet open and there was no sound. i sould also mention that my cambelt service is due shortly. also dont know if im being paranoid but the car seems to have lost abit of power too, dont knw if all this is due to the srvice coming up. cheers lads.

[Syndrome]

scoobyPPP said:

i sould also mention that my cambelt service is due shortly. also dont know if im being paranoid but the car seems to have lost abit of power too, dont knw if all this is due to the srvice coming up. cheers lads.

It's perfectly normal for the car to feel a bit more lethargic than usual when the service is due, you'll notice a nice difference once it's done I assure you.

[ScoobieWRX]

Exhaust knock underneath....probably where it passes the transmission/propshaft tunnel.

[scoobyPPP]

also im looking for a good air filter for the sti

ive been looking at:

http://www.rogerclarkmotorsport.co.uk/shop_detail....

or this

http://www.rogerclarkmotorsport.co.uk/shop_detail.... (can anyone tell me if this what is in my car at the moment as standard_

also any advice on iridium plugs

cheers.

[ScoobieWRX]

Stay away from Iridium plugs. Stick to NGK 'R' PFR7B Platinum plugs. Perfect for your average modified scoob upto 400+bhp. I used to run Iridium and they were truly awful. Terrible starting problems and misfired at higher loads plus low-mid revs. Changed to PFR7B and all was well again

As much as i love all things RCM that STi filter is very expensive for what it is and although it looks very nice with STi printed on it nobody is ever going to see it so not much point in that.

In comparison the Cosworth Filter is much cheaper and does the same job as the STi filter however for around £45+VAT a green panel or K&N flat panel filter will do a cracking job and flow up to 45% more air than the std panel.

[RASTIVL]

ITS YOUR HEAT SHIELDS ALONG YOUR EXAUST MANIFOLD OR UP AND DOWN PIPES MATE OR A CLEARUNCE ISUE IF YOU HAVE BUMPED THE BOTTOM OF CAR ON SPEEDBUMP ETC , USE A METAL PIPE AND GO TAPPING ON EVERYTHING YOU CAN TOUCH YOU WILL HEAR IT AS SOON AS YOU HIT THE LOOSE ONE ,
DONT BUY ANY OILED AIR FILTERS THEY WILL MESS UP YOU AIR MASS SENSORS AND MAKE YOUR CAR RUN RICH OR LEAN , OR EVEN STALL AT LIGHTS WHEN COMING TO A STOP , USE ITHER TIGHT STAINLESS WEAVE FILTER OR FOAM SUCH AS BLITZ BUT KNOW OIL COATED THEY ARE A NIGHTMARE WITH STANDARD SENSORS , STICK WITH STANDARD INLESS YOU ARE INCREASING POWER BY 50 60 HP , CHEERS

[scoobyPPP]

cheers for that mate was just wandering if you could provide me with more info on teh filters, are the two that i listed above oil filters as well as the green panel and k&N ones. been trying to look for the stainless air filters but cant find any, cheers

[scoobyPPP]

any1 know if these are any good?

http://www.scoobyparts.com/acatalog/HKS_PERFORMANC...

[ScoobieWRX]

scoobyPPP said:

any1 know if these are any good?

http://www.scoobyparts.com/acatalog/HKS_PERFORMANC...

PFR7B's work extremely well for modded Scoobs. I won't use anything else now and i couldn't tell you anything about the HKS plugs.

[ScoobieWRX]

RASTIVL said:

DONT BUY ANY OILED AIR FILTERS THEY WILL MESS UP YOU AIR MASS SENSORS AND MAKE YOUR CAR RUN RICH OR LEAN , OR EVEN STALL AT LIGHTS WHEN COMING TO A STOP , USE ITHER TIGHT STAINLESS WEAVE FILTER OR FOAM SUCH AS BLITZ BUT KNOW OIL COATED THEY ARE A NIGHTMARE WITH STANDARD SENSORS , STICK WITH STANDARD INLESS YOU ARE INCREASING POWER BY 50 60 HP , CHEERS

These types of filters are tried, tested and proven to be excellent. 300 miles or so after fitting a Green Panel or K&N Flat panel filter pop the MAF sensor out and give it a clean with brake cleaner, job done!!

It's people that never bother to clean their MAF's regardless of which filter they use that end up having problems with MAF sensors going down. They get dirty very quickly and the crap builds up to quite a thick layer if not looked at regulary so pop them out once a month and give them a quick spray clean. Before i map any newage scoob i pop out the MAF sensor and inspect it. 9/10 sensors i pull out have never been cleaned and end up with a very thick layer of crap built up over years and that's with a std filter fitted. It's no wonder they break down!!

Also, perhaps next time you post you might like to use lower case lettering

[alfa daley]

Ok newbie question as I have an Sti PPP and think I might give the MAF a clean but where is it? I'm assuming its a sensor after the air filter but before it goes into the engine?

[Syndrome]

alfa daley said:

Ok newbie question as I have an Sti PPP and think I might give the MAF a clean but where is it? I'm assuming its a sensor after the air filter but before it goes into the engine?

It's the square thing with the wires coming out of it that sits on top of the air pipe just after the airbox.

[RASTIVL]

older imprezas do have much tuffer maff sensors which you can clean easiy , but i was thinking of the 97 on which has a very delicate sensor which i could not clean , i went through three of them , water also efects it when salt build up on it ,if the sti one is a genuine part then i am shure it would be fine but the green and k&n ones do use oil , if you have the old maff then it dont matter bit of brake cleaner every now and then and it will be fine .