I have been struggling with this problem for a while also. Trips to garage have not revealed anything. Had the ECU fault codes checked and ECU reset but still persisting.

Would be extremely keen to hear if anyone resolves this - the loss of power (and driveability) is driving me nuts.

Really weird thing is that everything had been working well for about a year - but lost power after a service/MOT. Went back at the time but garage couldn't see how anything they did would cause a problem and the ECU had no codes.

If the PPP map turns out to be the prime suspect then I may just have to find the funds to get a custom map done.....(and maybe a sports cat to make it worthwhile )

B

 

further update (will this ever end?!) - took the car back to Cutlers Subaru today - they are a really helpful bunch by the way - having had a new MAF, new fuel pump, they are (like me) now certain it is the PPP ecu map. they have cleared the ECU again, done a 'soft' reset, and it drives fine again... for about 10 miles, then i can feel the 'problem' creeping back. Cutlers have taken my Prodrive certificate & warranty details. Basically, if i tell them it's still not right (which i will no doubt be doing in a couple of days) they will get the Prodrive area Representative on the case. The problem being that they do not have the equipment to re-map at Cutlers.
So, it's getting closer to a resolution, I will of course keep everyone posted on what happens if Prodrive get involved.
laterz, Chris.

 

Wonder if my change of fuel somehow forced a soft reset.... I've also emailed Prodrive to see if they have any idea what is going on.

 

weatherman - good luck with Prodrive! i've had no response yet..... I would try emailing IM through their site, i got a response quickly - no answers, but at least i now have a name! laterz, Chris.

 

Hi iunchabar - i agree - i think it is the ecu.
Each time my ecu has been reset the car is fine for a week or so and then gradually the problem comes back.

Like yours, mine is worse in the wet - don't know why.....

Pls keep in touch and let me know if you get it remapped - i am considering the same thing
take it easy
spb

 

I had my car in AWD and they identified the AFR sensor as the culprit - getting the new one in a few weeks will let you know how I get on.

wm

 

Had a friend take a look at the ECU (cheers Wuz), while here were no error codes the advance multiplier has reduced down to 0.3. Definitely seems to suggest that (at least in my case) that the ECU is detecting detonation and doing this on purpose and trying to protect itself.

There are a number of reasons this may be happening - but I can realistically rule out the prime suspect (fuel is always Tesco 99 or V-max).

Will be taking the car back to the garage that installed the PPP, hopefully will be able to check sensors etc and get to the bottom of this.

B

 

By the time you've gone back and forth umpteen times, messed about with Subaru dealers and all the rest of it, you could have had an Open Source or EcuTek remap and cured the issue. Yes it would cost money but think of the enjoyment and pleasure you've missed out on with all hassle you've had. In fact a trip to an independent specialist may well have sorted all your woes. Good luck with it though and hoepfully it hasn't put you off Subaru's.

It's very odd that it's only happening with PPP scoobs, or maybe it isn't. Doesn't say a lot for Prodrive's PPP

 

Its just a problem with a one size fits all map such as PPP. Its like borrowing a suit from someone who has the same waist size but is 6 inches taller - it just isnt going to fit aswell

 

Duncan, If you tried one of my suits on you get the the whole family in as well. Nice to know you're still alive and kicking!!

 

guys, since the ECU was 'reset' by subaru, it has been a lot better, but not perfect. I am probably going to get it remapped to be honest, that seems to to be generally the best, and only lasting cure. Just saving the pennies to get an upgraded air-filter and sports-cat down pipe at the same time and get it all mapped together... happy days! Laterz, Chris.

 

iuchabar,

Glad to hear you are going for a custom remap - as Duncan (and just about anyone else on SN) will attest this is definitely the way to get the most from your particular vehicle.

I will shortly be embarking on the same journey (sport decat, centre decat, Cosworth Blue filter, 255 fuel pump plus a remap). I am also hoping to get a VF43 to really spice things up.

My only caveat is that I am going to try and double check EVERYTHING when making the changes just to make sure the ECU wasn't picking up on a problem and protecting the engine from damage.

B

 

yeah - i already had a plug-in which showed some very minor detonation but (we assumed) not enougfh to make the ECU retard the timing etc... or go into error state so should be safe to remap.

laterz,

 

Sometimes a bad flash can cause an ECU not to raise the IAM after a reset. It may not be apparent when it's first flashed but sometimes they can get an internal software error which stops IAM rising after the ECU has pulled a lot of timing despite a lack of detonation or anything else and it won't re-learn fresh values.

The only way you know the ECU likes the reflash is if the IAM (Initial Advance Multiplier) rises fairly quickly after a flash. You drive around for a couple of mins, pull over, stop the engine. Wait 30 seconds, restart the engine and drive around for a minute or so, then in third gear drive along steadily for a few secs and then raise engine revs adding more engine load as you feel the car pick up. A fairly swift rise to an IAM of 16 (2Ltr 16-bit ECU's) or 1 (2.5Ltr 32-bit ECU's) is a sure sign it's OK.

Sometimes they take a little bit longer but doesn't normally take too long. If you struggle to get the IAM up then either it's a bad flash, there's something wrong with the ROM that's been flashed, or some of the maps have been tweaked too far to the point it doesn't like it. Either way a flash with a fresh ROM image is the way forward.

Also, the best way to know if your ECU is buggered is to flash a std factory ROM back to the ECU. If the car drives well after learning fresh values then you know the PPP ROM was a bad flash. If it still drives badly then likely the ECU may be faulty.

 

Latest (and hopefully the end of it all now) - Cutlers Subaru had my car over the weekend - the ECU has been reflashed by Prodrive, the knock sensor replaced i think, exhaust checked and tightened... then they found a cracked spark plug! Could that have been the root cause all along? Not so sure, but suffice it to say the car now runs like new... strangely the engine seems a lot smother and quieter too. Boosts back to 1 bar, pulls with no stutter etc... so we'll see if that sticks now. Can't fault Cutlers, they have been helpful all along. So to all you people with WRX ppp issues like this, check the plugs!!!!!! (lol), but also keep onto Subaru / Prodrive to get a reflash if under warranty. Laterz, Chris.
ps - i will probably still get a custom remap when money allows and once the car drops out of warranty, as i think this is still the best way forward.

 

Thanks for the update and good luck with the car - hope it continues to behave!

How did you get prodrive to do a reflash? They are just ignoring my emails to them now and the car is getting worse!

I am out of warrenty but this problem has been an issue for two years so I will revert to pushing Subaru again.

 

From what you've said it sounds like it was a bad flash after all and the ECU just got it's knackers in a twist. Not so sure i believe knock sensor, cracked spark plug or leaky exhaust. A bad flash can make it run really dog rough.
Glad you got it sorted though. Very tenacious!!

Nice one

 

spb123 - my local subaru dealer (Cutlers) were very helpful. They basically oraganised it all. Again, not sure i am totally convinced about some of the information (plugs?!) but hey, the car is ruinning better now, so fingers crossed they have sorted it. My big advantage was the warranty and i had all the paperwork to support that. I guess you will just have to keep on at Subaru and try to get them to talk to Prodrive... Best of luck, keep trying becuase even if it's out of warranty it's worth making it better! Laterz, Chris.

 

Strangely, although I haven't yet had the AFR sensor replaced, the acceleration has been back to normal for a few weeks now. Still a bit of jerkiness from cold on occasion but maybe the existing AFR sensor is sending reliable enough looking data now to prevent the ECU retarding the timing.
Another possible cause of the poor acceleration was pointed out to me that it could be a sporadically sticking turbo vane.

 

surely a sticking turbo vane would be MAJOR noticeable though? - like serious on/off performance rather than just jerkiness?
And surely it would very quickly become catastrophic for the turbo?

My car started to go funny again btw - i haven't bothered contacting Subaru, i've given up now (since they said if it went again it must be a cracked piston so that would be at my expense to strip the engine.... yeah right) - they were very helpful to a point, but now i think they just want to see the back of me as the warranty is up this month...
anyway, i fitted a grounding kit (thanks to Pete at Groundingkits.co.uk) - and hey presto, it was fine again - but not sure if that's due to disconnecting the battery doing a soft reset on the ECU, or the actual grounding kit making it run more smoothly.... we'll see.

Y'know, i used to have a Nissan Pulsar GTi-R - i got it to 300bhp, no ECU issues, no engine issues, change the boost, filters, exhaust... didn't miss a beat, it ran like a demon... and that was a 1991 car! Come on, Scooby's got to be better...

 

Disconnecting the battery, even for an age on a newage car won't reset the ECU because it uses non-volatile memory. You can only do that with diagnostic kit.

If it was a cracked piston your car wouldn't be great for a while and then one day go lame, it would be bad all the time. Suabru's are brilliant cars and generally most relaible both electrically and mechanically. You have an issue that is probably slapping everyone that's looiking at it in the face but it's just too obvious to see.

Everytime you reset it's fine for a while and then it goes lame. Is this after a spirited run or you just start the car one morning and it's playing up.

I've seen drops in IAM on an STi a while back. It would't take any more than factory boost levels. I diagnosed the issue down to the Forge dump valve that just wasn't holding boost due to a very soft rated spring so as soon as boost went over factory it pulled IAM very quickly.

Subaru have presumably checked all your sensors and given them the OK so that that leaves something that's either still ECU related or something a bit more obvious that only happens under certain conditions.

 

so how come disconnecting the battery suddenly makes it seem better?
it tends to be fine for a while, then gradaually gets worse over time - not a sudden change, but you notice straight away as it goes 'off' (becoming lumpy and jerky at low revs) - and no, it's not when i boot it... eventually it ends up dropping boost to 0.5 bar and then it's game over for performance.
Very weird.
it's got the stock recirculating dump valve on btw.
ta.

 

I promise you now your newage ECU will not reset after disconnecting the battery. It is only possible with with diagnostic kit. That could potentially be the ECU at fault then feeling better after reconnecting the battery and soon losing it again, for what reason i don't know right now without looking. You haven't ever had a leak from the heater matrix in your car have you?

The reason i ask is that someone called me the other day to ask about another ECU as his heater matrix had leaked quite a bit on the passenger side, and with the ECU being bolted to the passenger side floor/firewall it got wet and has been running like a bag of ****e ever since.

Just a thought

 

Its a long shot, but worked for me.
I had slight hesitation & jerkiness as turbo was coming on around 2.2-2.6k revs and noticed it more in 4th & 5th.
I have 2.5 WRX with VF34, mapped.

Previously I had done an oil change (10w 60 as told). What it turned out was that although I had filled the oil up to the right level on the dipstick, this somehow lead to excessive oil vapour being put through the boost solenoid and causing the hesitation / stuttering coming on boost.
I now run with my oil level (on the dipstick) about a third of the way up between low and full, also it would do any harm to spray the boost solenoid with electrical cleaner (yep, the halfauds yellow and green tin) to clean what has been left in there.

Unlike the classics though, the green plug trick doesnt work, so you have to spray in the pipes and solenoid just before starting the car and heading off (so that the solenoid opens and closes to let the cleaner in), if you dont do it quick enough, the cleaner just evaporates prior to entering the solenoid as its shut closed when off.

Ultimately, I think its due to the 2.5's being "very heavy breathers" and probably why PPP cars are noticing it more and on colder mornings too.

Solution (to me anyway) seems to be install oil catch cans.

Let us know how you get on.

 

Well after a month or two of running OK I finally got the AFR sensor replaced. On the next long journey, after about 100 miles the problem returned. The transition from coasting to part throttle was very jumpy/lurchy but then there was little boost at low to medium revs (accelerating from 60 in top for example) still seemed to be boosting at higher revs but the reduction seemed to be less.

I had filled up with Tesco 99 for the first time (V Power was out of stock again) but I don't think that was the issue. It was a very wet journey in places though.

I filled up with V Power towards the end of the journey, and on restart, for the last few miels of the journey, the power was back to normal.

This is the second time that stopping for fuel has caused the problem to disappear, at least for a time. I wonder if it is just enough time for something to cool off, eg minor leak sealing up, overheating sensor cooling down.

 

It might be worth hooking up some diagnostic kit to see how it's running on the road. Not a handheld device but a proper laptop based diagnostic that records/logs data that can be played back in order to pinpoint where you're getting an issue.

If your ECU isn't already mapped (or even if it is) it might be worth overwiting the existing ROM on the ECU for a Factory fresh ROM having saved your original ROM first if it's been mapped. You just copy over all your original settings and it's mapped as it was.

Your ECU may have got it's knickers in a big twist at some stage and corrupted the ROM, as can happen. In the past i've come across ECU's with the same issue cropping up time after time, even after several resets and after much fault diagnosis showed no issues with any of the sensors. Very often flashing a Factory fresh ROM will clear ECU related problems that don't show up under normal fault diagnosis.

 

Thanks scoobiewrx.

I'm beginning to think it is ECU rather than something mechanical, or at least purely mechanical.

Why?

Well my last 150 mile journey, broken by a petrol stop, was fine all the way. Annoying actually as I wanted the slow mode to be apparent when I passed my favourite Subaru specialist so I could hook it up to the diagnostics.

Then today, towards the end of a 150 mile stint, I'd noticed slow mode in operation for the last 50 miles.

So, just before I got home, after coming off the motorway, at the slip road exit I decided to switch off the engine, just for a few seconds, then restarted it. All of a sudden slow mode disappeared, and the last 10 miles were back to normal.

Now slow mode is really slow, like 11 seconds 60-80 in top, normally it's around 5.5.

I'm convinced something in the ECU decides to restrict boost, but is reset on an engine switch off, no matter how brief. Yet I've seen it categorically stated that an ECU reset can only be carried out by a dealer.

Now, what other problem could be temporarily cured by just turning the engine off for a few seconds?

Of course something might be triggering the ECU to retard things, eg false det, real det, but would that reset itself after a switch off?

 

A buggered ECU can play up in all sorts of ways intermittent and otherwise. There is only one way to eliminate the ECU completely from your equation and that's to replace it. For what it costs to buy one and then take it to a dealer to have your keys synchronised it may well be worth it baring in mind all the hassle you've had this far.

If it turns out not to be the ECU you can always sell the original one for what you pay for a new one.

The easiest thing to try is a reflash but that's still no guarantee of a fix if it's an ECU hardware issue although it's very quick to do.

 

Would have thought it would be quite expensive to go along that route and then get the PPP map put back on? And how would I sell a used ECU for the price of a new one?
Anyway I expect the best thing to do is as you said on your previous post, get a laptop connected while in slow mode, then again turning off the ignition to connect it might disable slow mode!

 

You don't buy a new ECU, you buy a 2nd hand one to replace yours. You misconstrued what i said.