Lack Of Power

[simboy73]

Afternoon all, i've had my 03 plate WRX (76K) for about 6 weeks now - was going great and sounding great until yesterday...

The turbo's whooshing and whistling as normal but the oomph seems to have gone - alittle, it's still nippy but not as nippy as it was and the roar from the back back isn't as loud as it was...

Does that mean it's not boosting properly or am i looking at CAT problems...? I'm at a loss...

It does still go OK but just not as it was...

Or is it we've gone from cold weather to hot and scoobies don't like warm weather.?

Cheers

Si

[mystery machine]

Have you been pottering about much recently? I'm told that prolonged periods of sedate driving can cause the ECU to pull back the boost/timing a bit (part of the continuous 'ECU learning' algorithm). Certainly notice it with mine - power delivery diminishes after a week or so of going back and forward to work. Can take up to 200 miles of spirited driving to persuade it fully back into 'fun' mode (although you notice it gradually picking up as you drive those 200 miles).

We're not talking drastic power reduction, but most certainly noticeable!

Are you using 99 RON?

[mystery machine]

P.S. Generally don't notice much difference in engine performance between hot and cold weather, aside from on very cold winter days - where, once the engine has warmed up, there's generally more boost on tap (the dense air, I guess).

[Big P UK300]

I had a similar problem last year , took it up to AWD in Perth and they told me it was a sensor that needed replaced .

I paid £400 for the work , and within a month it was doing the same again. It still does it to this day

Some days the car feels fine , others it feels as if someone has dissconnected my turbo , havent had it looked at since . If the guys at AWD who work with them everyday cant figure it out what chance have you got !

[dipsy]

I had a similar problem last year , took it up to AWD in Perth and they told me it was a sensor that needed replaced .

I paid £400 for the work , and within a month it was doing the same again. It still does it to this day

Some days the car feels fine , others it feels as if someone has dissconnected my turbo , havent had it looked at since . If the guys at AWD who work with them everyday cant figure it out what chance have you got !

What about going and seeing Andy F and checking the ecu with the ecutek software to see if there is any faults.I got told the ecutek software can pick up things over the select monitor

Edited April 21, 2009 by Dipsy

[simboy73]

You've hit it on the head.. I've read about the ECU learning your driving style... This last week or so i've been pottering about and been getting good fuel figures...

So the answer is maybe give it a wee ragging and it'll hopefully go back to normal..

I read about the ECU issue in the Essential Buyers Guide... It's an intuitive ECU... Clever bods those Subaru Lads 'n' Lasses

Also, someone mentioned ANDY F - i don't mean to be rude, who is he and where is he based.. I take it he's a Subaru specialist.

Si

[dipsy]

http://andyforrestperformance.co.uk/index2.html .Here's his website

[mystery machine]

So the answer is maybe give it a wee ragging and it'll hopefully go back to normal..

With a bit of luck, mate. Although do be prepared to have to rag it for quite a few miles before it starts to feel as keen again.

I was off work for a week recently. Every trip I made I tried to turn into a little fun run (within reason, within the law, etc). Car never felt better than it did after that week of spirited driving. For similar reasons, it always feels a bit keener on a Monday morning than it does on a Friday night - even if I don't!

Also, someone mentioned ANDY F - i don't mean to be rude, who is he and where is he based.. I take it he's a Subaru specialist.

He's a Subaru tuning specialist:

http://www.andyforrestperformance.co.uk/index2.html

Never used him myself, but legend has it he's the local guru on all things Subaru ECU. Seems to have made many a happy customer around these here parts... I'd imagine he's well worth a try if your problem turns out not to be related to ECU learning.

Edited April 21, 2009 by Mystery Machine

[simboy73]

Thanks Again Folks - time to fill it up and keep the thottle pressed a little harder. Clearly Scoobie's weren't meant to be driven so sensibly..

Si

[mystery machine]

You're welcome.

Aye, does it good to keep the revs up on a fairly regular basis. Let's face it, you didn't buy it for its fuel economy

[dipsy]

Go on a good run that cleans them out .

[Midnight21]

I also noticed a big difference using V power, think I got a bad batch of tesco's 99 though and a few people who used it at the same time did too! So sticking with the shell now...also picked up a shell points card

[Big P UK300]

What about going and seeing Andy F and checking the ecu with the ecutek software to see if there is any faults.I got told the ecutek software can pick up things over the select monitor

Cheers for the advice ,

Seen his name mentioned a million times on here but thought you just went to him for a bit of tuning , never occured to me that he would sort problems out aswell

Thank's again

[lumsden26]

hi had my classic on a 850 miles trip and could only use the lower octane and i noticed a huge difference even though i'd been giving it a good thrashing seem'd to take ages to pick up in 5th but i'm back on the v-power had two fills and is back to normal. apparently the ecu takes longer to adjust up the power range than it does to when your taking it easy.

[mystery machine]

apparently the ecu takes longer to adjust up the power range than it does to when your taking it easy.

I've heard this too, and it ties up with my own experience.

I also understand that if the engine is subjected to a lower-octane fuel than it's used to - and the ECU detects knock as a result of this - then the timing will be retarded pretty much instantly. Again, it'll take several miles, judicious use of revs, and maybe even a couple of tank-worths of 99 RON to advance the timing to its previous setting.

The Scooby ECU is apparently very much "once bitten, a hunner times shy"

[P1_Paul]

Hi guys, just to be clear, the ECU doesn't reduce timing learned or otherwise if you drive your car sedately.

[mystery machine]

Hi guys, just to be clear, the ECU doesn't reduce timing learned or otherwise if you drive your car sedately.

I admit to being hazy on the exact technical details - perhaps 'timing' is the incorrect term - but the senior servicing chap at Ian Grieve Subaru told me quite confidently that the ECU adjusts certain 'parameters' according to driving style which can effectively make the car feel more or less responsive over a period of time.

If you have a better understanding of Subaru ECU learning, I'd be genuinely interested in hearing more. Any research I've done on the topic has turned out only the haziest of details...

Edited April 23, 2009 by Mystery Machine

[P1_Paul]

I admit to being hazy on the exact technical details - perhaps 'timing' is the incorrect term - but the senior servicing chap at Ian Grieve Subaru told me quite confidently that the ECU adjusts certain 'parameters' according to driving style which can effectively make the car feel more or less responsive over a period of time.

If you have a better understanding of Subaru ECU learning, I'd be genuinely interested in hearing more. Any research I've done on the topic has turned out only the haziest of details...

Nah, the only real learning as such is the timing, it has 3 ways to adjust timing, one immediate and 2 'learnt'. There is no learning at all on the boost side of things. I'd have offered to hook the car up to my laptop if the OP was closer, it would only take 5-10 mins to tell you if it's sick.

Edited April 23, 2009 by P1_Paul

[mystery machine]

Nah, the only real learning as such is the timing, it has 3 ways to adjust timing, one immediate and 2 'learnt'. There is no learning at all on the boost side of things.

Interesting, cheers for the reply.

Got to admit that it doesn't quite tie-in with my experience of the car. The more often it's revved, the stronger it seems to pull in general. There's a lot of chat on the internet about this behaviour (especially on the American Subaru sites), so it's hard to know what's for real and what's snake oil. Some supposed gurus are quite adamant about the effects of driving style on the car's general performance - even going as far as to publish means of accelerating 'fast mode' ECU learning...

We really need some clever firmware whizz to reverse-engineer the Scooby ECU...

[dipsy]

http://www.ecutek.com/tuning/ignition .Here some thing to look through about subaru ecu Edited April 23, 2009 by Dipsy

[P1_Paul]

Interesting, cheers for the reply.

Got to admit that it doesn't quite tie-in with my experience of the car. The more often it's revved, the stronger it seems to pull in general. There's a lot of chat on the internet about this behaviour (especially on the American Subaru sites), so it's hard to know what's for real and what's snake oil. Some supposed gurus are quite adamant about the effects of driving style on the car's general performance - even going as far as to publish means of accelerating 'fast mode' ECU learning...

We really need some clever firmware whizz to reverse-engineer the Scooby ECU...

The fast mode ECU Learning is a method of increasing the IAM value after a ECU reset(or a decreased value due to knock etc). Sometimes th IAM increases quickly, sometimes it doesn't, I've found it depends on the car.

The car has been reverse engineered a good number of years ago, fistly by ECUTek, then the OS community.

[mystery machine]

Dipsy - I was reading a similar article on Andy Woods' website the other day - lots of general ECU info, but scant detail on the 'learning' side.

I'll check out that ECUTEK link, though - cheers!

[mystery machine]

The fast mode ECU Learning is a method of increasing the IAM value after a ECU reset(or a decreased value due to knock etc). Sometimes th IAM increases quickly, sometimes it doesn't, I've found it depends on the car.

Aye, that sounds familiar. So what effect does the IAM value have on the way the engine runs? If 'IAM' stands for 'Ignition Advance M[something]' then I think I know the answer

fistly by ECUTek

Jings, that sounds a little 'invasive'

[P1_Paul]

Aye, that sounds familiar. So what effect does the IAM value have on the way the engine runs? If 'IAM' stands for 'Ignition Advance M[something]' then I think I know the answer

Jings, that sounds a little 'invasive'

LOL.

In a few lines, it goes like this -

IAM is a value 0-16 in 16bit ECUs(UK - 01 - 05) and 0-1 on 32bit ECU's(UK - 06+), there are two timing tables, base and advanced(combining both values to get total timing). IAM determines how much timing the ECU uses from the advanced table, e.g. a cell calls for 10 degrees, if your IAM is 16 then you get 10 degrees, if it's 8 then you get 5 and so on....there's a bit more to it than that, but that's the basics. Essentially, you always want your IAM to be either 16 or 1, depending on year.

[mystery machine]

IAM is a value 0-16 in 16bit ECUs(UK - 01 - 05) and 0-1 on 32bit ECU's(UK - 06+), there are two timing tables, base and advanced(combining both values to get total timing). IAM determines how much timing the ECU uses from the advanced table, e.g. a cell calls for 10 degrees, if your IAM is 16 then you get 10 degrees, if it's 8 then you get 5 and so on....there's a bit more to it than that, but that's the basics. Essentially, you always want your IAM to be either 16 or 1, depending on year.

OK, so if subjecting the engine to certain conditions can affect the IAM value (e.g. when forcing fast ECU learning), and the IAM value affects ignition timing advance, then doesn't it follow that driving style can affect ignition timing? Perhaps not constantly, but at least under certain conditions - e.g. after a change in fuel, or after an ECU reset...

BTW - cheers for all the info, it is appreciated.