Jap Imports

Hello, 2005 JDM STi

i gave my car a big thrasing in wales at the weekend also with all 4 wheels in the car and some light grounding out... after all of this i have what sounds like from the exhaust a slight engine missfire, and the engien is a little rocky at idle and at low rpm.....

Any Idea's...??


I have renewed the plugs today with PFR7B in case a bit of carbon had broke off and was in the plug gap, but no different?

M535I

well if you abuse it to hard thats what happens !
oil starvation ? split lead ? u tried an ecu reset incase one of the sensors has gone abit nuts after your antics ?

Jap Imports

Oil Starvation to what?

Its got coil packs


How do i reset my ECU , remember mine is a 2005 JDm STi,

I didn't redline it any gears, but it was gunning for a long time, up and down gears hard!!

merlin24

iTrader: (1)

Do a Compression Test to confirm the Internals of the engine are ok.
Then look at the plugs,coil packs,fault codes in the ecu.
BTW - was it you who had the ticking noise on the LH head and did you sort the problem out ??

Mick

Jap Imports

Hi yes i did have the ticking noise... i stripped it down, found nothing really, sent head away to be tested and they replaced the valve guides as they had some play in them, fitted back together and ticking noise gone!...

Done 800 miles in it, and now i have this problem!

Changed the spark plugs (PFR7B)
Checked for Fault Codes (None Found)

Coil Packs (Still To Test)
Compression Test (Still To Test)

merlin24

iTrader: (1)

Think you need to do a Compression Test first and then a Cylinder Leakdown test to see whats what internally.
Could even be a tight valve clearance causing the uneven idle and slight mis-fire.

Mick

Jap Imports

Yea true, could be a valve clearance probelm, will try and get compression test done tomorrow, shall keep you posted!

John

Jap Imports

Compression Test Done.

Right Bank both at 90 !!!
Left Bank both at 120

merlin24

iTrader: (1)

Compressions are well down - they should be between 140 - 170 psi (cranking with the throttle wide open).
Minimum Compression should be approx.125psi IIRC.

Mick

Jap Imports

How about if he wrong thickness headgasket has een fitted, ifso why the problem after 300-400 miles!

DIPSY

Is there a difference from PFR7B to the PFR7G which are fitted in the newage Jdm Sti it says this in the back of the Japanese subaru owners manual .I have 05 Jdm Sti

merlin24

iTrader: (1)

Your '05 JDM STi should have thin MLS(multi layer steel) head gaskets fitted.

Jap Imports

Yea it has the MLS gasket, but a 0.55 was fitted and it should have a 0.50mm i have been told... !

Jap Imports

Check this out :

Spark plugs uk, NGK, Champion and Denso spark plugs

NGK spark plugs symbol code

merlin24

iTrader: (1)

Shouldnt alter it much as its only just under 2 thou difference between the gaskets.
Thought the Subaru thin steel gaskets were 0.60mm compressed ??
IIRC,the left hand head gasket has been changed recently due to the ticking noise you had but the compressions are down on the original right hand side.
A leak down test will narrow it down a bit - head gasket/valves not seating/ring blowby etc etc.

Mick

Jap Imports

No Right hand has been changed due to ticking noise, nothing found, and put back together with new valve guides etc and then no noise, and now its down on compression that side too.

John