the_big_1

iTrader: (1)

Hi All,

My standard 2006 STI always seems to be holding back, like a missfire a bit.
Last week I changed the plugs and it seemed to be better.
Now it seems to be hesitant until about 3000 rpm then feels ok.
Any ideas?

LegacySTi

iTrader: (13)

wat type plugs?

the_big_1

iTrader: (1)

I just put standard new plugs in.

the_big_1

iTrader: (1)

Anyone guys?

scooby L

fuel? when did u last fill up and with what

the_big_1

iTrader: (1)

I fill up about every two days due to the miles I do. I always fill up at Sainsburys super unleaded.

scooby L

Might just be all the advance has been wound in due to the fuel...Sainsbury's isn't the best fuel to run STI's on.

Best way to tell is to stick 3 tanks of Tesco99 or V power in it, and see if it still feels lacking

The warmer weather will "test" the detination limits of your motor more than the winter

the_big_1

iTrader: (1)

Is there anything can be done like it be dialed in better on a re-map?

scooby L

the advance may have been wound back for a reason.... high detination...not engine friendly! a remap will not solve this, putting better fuel in will

the_big_1

iTrader: (1)

Would ir explain why it runs bad up to 3K then fine after that?

scooby L

You'd expect to find detination "spiking" around 2.5k-3.5k.... when the boost curve is steepest and torque is increasing the most....so higher gears on WOT (2.5k-3.5k) would send my old 2003 Blob's knocklink mental on anything other than V Power. But it was mapped for V Power so no surprise.... yours is standard, so not as critical... but Sainsburys SUL aint the greatest, even for a standard STI

the_big_1

iTrader: (1)

Mine seems to the isue at about 1500 up to about 3000 same thing?

scooby L

Most likely, the 2.5 spools up quicker

It's just the engine protecting itself as best it can... but the trade off is less power.

You got to remember the STI is subaru's highest tuned car in standard form... but it requires very good fuel to perform safely....

the_big_1

iTrader: (1)

Will try some Tesco's 99 in when this is used up. I have 3 /4 tank in it now, anything I could put in to make it better to use it up?

scooby L

you could add bottle of octane booster, but to be honest I'd just not cane it till the tanks nearly done and fill up with 99... the advance will slowly recover...which is why I said 2 or 3 tanks before you'll notice a marked improvement, but after a tank it may feel a bit more eager

the_big_1

iTrader: (1)

I can reset the ecu once the 99 is in it? I can do it with my lap top.

dynamix

iTrader: (3)

Any modifications to the exhaust system ? I know you say standard but is it 100% standard ?

A Remap can be done on whatever fuel you want to run it on but the best results come on vpower, then tesco99. Sainsbury super is way down the list but can still be smooth, safe and powerful on that.

the_big_1

iTrader: (1)

The only exhaust mod is center pipe and Ninja II back box. Also K & N Pannel filter. Thats it.

dynamix

iTrader: (3)

That will be why it is doing that then. The 2006 Sti is very fussy when it comes to unmapped changes in exhaust components. The ecu is very good at protecting itself though which is probably what it is doing here along with a degree of removing the restrictions in the std exhaust making it boost more freely.

the_big_1

iTrader: (1)

I was told many times on here that along as the CATs where left on it wouldnt be an issue, is that not true?

dynamix

iTrader: (3)

It is the danger of following some advise on here tbh from people that don't own the same car as your own (or have tuned a lot of them).

the_big_1

iTrader: (1)

So I have to put the old system back on then, bugger its been like this for 18 months now!

dynamix

iTrader: (3)

Has it been running like that for 18 months ?

the_big_1

iTrader: (1)

No I ment the exhaust has been on 18 months. If I reset the ECU, its fine for about a month then slowly it goes off. In freezing weather its fine etc.

dynamix

iTrader: (3)

Could just be the rubbish fuel ... try it on vpower (reset ecu afterwards) and see what it is like. There are lots of reasons for the advance multiplier to drop from 1 (which sounds like it is happening) fuel, det, overboost and mechanical faults.

Are you able to do some datalogging on your laptop and send me a file to analyse ?

the_big_1

iTrader: (1)

Hi,

I use ECU explorer so I would say yes, what would you like me to record?

V4JDMSTi

iTrader: (2)

One question - why are you hooking your laptop up to your ecu? Have you changed anything at all?

the_big_1

iTrader: (1)

No I only do it to reset the ECY when it runs really bad. I only use ECU explorer which will only read data and not maps or anything.

V4JDMSTi

iTrader: (2)

Ah I see. I'd just do it the poor mans way and disconnect the battery for an hour . Or in my case the ecu gets reset at least twice and month as my battery is normally flat where I don't get to use the scoob.

the_big_1

iTrader: (1)

lol that doesnt work on later cars lol