marklemac

I think perhaps a trip to a rolling road (PE) for someone just to check it out my be in order, especially if they can listen for det.

Time for a Knocklink I think.....Can PE supply and fit these ?

marklemac

**UPDATE**

I now have my Knocklink fitted. All is well according to the display. On full boost in 3/4/5/6 gears only 2 green lights max. Most of the time its just the one green light, and the 2nd one blinks.

Anyhow, after blowing away a Saab converable today off a slip road I found myself later having the limiting boost problem again.

Again, 10psi max boost.

I looked at knocklink when on hard throttle and it was fine.
I looked at the secs output and the figures haven't changed from normal conditions.

I'm wondering what to look at next.

Anyone with any suggestions ?

Should I look to be changing any parts/upgrading parts.

Comments welcome please.

marklemac

**Update**

Happened again last night, after giving it some major booty.

This time I watched what the SECS display was showing.

Boost is limited to 8psi (not 10psi which the boost gauge was showing).

So I did the following. Motorway was very quiet so I was in 6th gear.

I started to accelerate and the KC on the SECS was climbing nice and high as per usual. Got to about 10 degrees whilst the boost was being held back.

The AFR reading showed .76 which is the same as usual.

Knocklink - nice and quiet.

So, I basically held the accelerator down about 75% and watched the SECS boost display.

8psi
8.3psi
8.7psi

Then, just like something had become unstuck full boost came back 20psi.

I eased off the throttle, and then back on and full boost was there.

I know this thread is dragging on a bit, but I am trying to get to the bottom of what could be causing this 'sticky' effect.

Any comments please ?

marklemac

**UPDATE**

Problem occured again last week. A quick blast from some light, 1st gear, 2nd gear, into 3rd, overtake car, into 4th - boost holding back - 8psi.

Dammit.

continued crusing, into 5th gear and into 6th.

drop to 5th, full throttle 8psi, Knocklink nice and quiet.

So, I thought I'd try what I did last time this problem occurred.

Into 6th, get the revs down and then give it around 75-80% throttle, so the boost can get to its stuck position and hold there.

revs climbing, boost still at 8psi, more revs then just like last time (not sure what speed or revs) the boost moves past 8psi and shoots to full boost (around 20psi).

I really need some inspiration from some experts out there as to what I should be doing about this. The car is under warranty. It has been back to the dealer to have a new ECU fitted with the new PPP map on it.

I want to go back to the dealer but would like to give them some ideas of what might need changing.

Many thanks.

dowser

Does your IAM ever reach 16 now? If it was a mechanical problem restricting boost somehow, I'd expect IAM to be at 16 during the period of your problem. Is it? If so, look at dump valve or wastegate?

Basically, if IAM is still dropping while it is happening then it is your ECU shutting boost down to protect the engine from failure because it either thinks it is, or it really is, hearing det. End of story

Has your knocklink been confirmed to be functional with det cans? And is it on full sensitivity (a light tap with a housekey on the bolt holding the sensor should light big red)?

Have you modified the inlet path at all (ie; cold air pipe or new filter)? Have you compared your MAF voltage with another PPP car running the same boost level?

Might be time to take it to a reputeable EcuTek tuner for proper diagnosis. No disrespect to Subaru dealerships, but their mechanics are not always best qualified to diagnose this sort of problem. Depends how much you want to fix the issue though I guess, 'cos you'll have to pay

Good luck, Richard

Trashman

BUmp for this - Marklemac did you ever sort this problem as I have exactly the same?

marklemac

Hey trashman,

Well in a nutshell I did the following and I have never had the problem since then

I sprayed the WD40 as per one of the replies above.
I also installed the infamous earthing kit
I have fitted Samco hoses, and I also fitted a APS TMIC.

Now, since fitting those items I have never had the problem ever since.

Again, since then I've now had a TEK3, cold air feed etc and the car is much better.

So, to say what cured it ? mmm, wouldn't have been the TMIC. Maybe it was just the WD40 to stop the sticky arm. ?

Who knows...

Main thing is that the car is perfect now

Are you getting exactly the same problem ?

PM me If I can help further.

Trashman

Thanks mate - yes identical problems, only difference is mine is not PPP'd but this is the first post which describes the problem exactly the same - especially the bit about holding on high revs then booting it (it almost seemed like the noise abatement thing in 2nd gear). When traffic is busy I'm usually at high revs in 4th or 5th at the same spot every morning and when the car in front moves over and I boot it that's when it will happen.

TBH it doesn't happen that often same as you. Had the solenoid cleaned out month or so ago on last service, car is going in for some work any day so will ask the dealer to strip and clean waste gate actuator. Might be having PPP fitted at same time so should be easy job for them (I'll clean the thing and drive it, they can rap their knuckles and get dirty).

Thanks for coming back to me

marklemac

thought I'd bump this back up.

Did 250 miles today in the 35 degee heat, and half way through the trip the car decided to cap my boost, exactly as before. After about 30 miles or so, I managed to stop and turn the car off, back on, and the problem went away. Full boost was back again.

The car is now nothing like the spec when I first had the problem.

I wonder what is causing it....

JIM THEO

Mark if you see the STI PPP maps they have intake temp compensation and many more safety characteristics, your boost will not rise at normal levels even if you have low antifreeze temps/pressure etc so probably there are more than one reasons for your case.
When I have time I'll post for you some of those maps just to see what happens - bear in mind here in Greece due to higher ambient temps many people that don't know it complain about lower boost especially after periods of stop and go, traffic lights etc which is normal for the safety PPP offers.
JIM

JIM THEO

I have a friend that his failed radiator cap don't allow the anti freeze to reach the correct pressure thus his PPP STI boosts at lower pressure usualy.
He visited more than 3 Subaru services with no solution and we finally found ourselves the problem!

marklemac

Hey Jim - how are you ?

No it doesn't have PPP anymore, deleted that a couple of years ago !

JIM THEO

Very well Mark, some time away from forum as I was very busy but now I am back!

marklemac

Don't know if this is related, but found this article on the MRT website.

"DOES YOUR WRX OR STI SUFFER FROM AVCS PROBLEMS?
Some early build Version VII Sti’s (2002 bugeye) can have intermittent problems with camshaft control, manifesting itself by forcing the AVCS system into a failsafe mode. The problem is still evident in some WRX (MY03-MY05) and STi (MY02-MY05) models, however is less common. An indication that Subaru Japan were aware of this issue was that obvious mechanical design changes were made as the model progressed. Notably AVCS cam control hardware and related software. Whilst not logging a fault code in the self-diagnosis system, power and driveability are effected, and many dealers are not aware of the fault.

Where it does become a big issue is with modified cars, as power outputs can suffer quite dramatically as the system can no longer take advantage of the extra airflow generated by more efficient exhaust systems and higher boost pressures etc. MRT have invested hundreds of hours in this problem and have narrowed it down to several areas. If you own an early model Bugeye STi (or later), or a 2003-2005 WRX or STi and suspect that the AVCS system is not functioning properly, see your nearest EcuTeK agent for assistance, or email or call MRT on 9767 4545 to book in for a check-up."

Bob Rawle

The problem is simply ProDrives mapping, they use temp compensation to limit boost. To be honest if any other tuner tells you its a car type problem (even MRT) they are talking pants, mapping is the key. I have NEVER had a car suffer like this.

cheers

bob

marklemac

The car doesn't have PPP on it, and hasn't done for at least 18 months.

Bob Rawle

Still as I said but substite whomever for Prodrive, depending on the rom used there are four settings that influence this, two are ign retard related and two are a.m. related.

cheers

bob

sgcooby

I started a thread about this exact problem on my car which is in General Technical section at the moment. ( Dont know how to post links) Its called "WRX power dropping off." The comments on here made earlier about the waste gate arm sounds feasible and i will definately be spraying some WD40 in there later on but i still find it strange that my problems only started straight after i got it ecuteked. Surely a sticky waste gate arm would have been doing this previously? When i took my car into my mapper when this problem occured there was no fault codes and the multiplyer was still up at 16 so the engine hadnt retarded it after sensing something. On the occasion i took the car to the mapper the problem luckily happened just 2 minutes from his garage so there was no way the multiplyer could have dropped and then advanced up to 16 again so maybe this does point towards a mechanical issue. i.e waste gate arm.

From what ive heard on here my course of action is going to be as follows.... 1) WD40 onto waste gate arm, 2) Replace airflow meter if 1) fails, 3) Replace boost solenoid if 2) fails, 4) Shoot myself.
Be interested to hear how others have got on with this problem.

marklemac

ok just to clarify:

The car was ppp'd 2 months after buying it. I did not experience the problem before the PPP.

Whilst in the PPP state of tune I experienced the problem around 4 times.

PPP has not been on the car for 18+ months. In those 18 months I have fitted.

injectors
turbo
tek3
headers
3" exhaust
new maf
fmic
fuel pump
fuel regulator
3 port solenoid
pulleys


Since then I have experienced the problem once.

Lets hope it stays that way. Not much else I can replace.

Bob Rawle

Ask for the settings to be adjusted, permanently sorted, no need to do anything but take existing map, adjust four settings, flash it back, no rolling road, no driving around.

The ecu doesn't have drop the advance multiplier when this happens, its a different set of parameters. AM reacts to retard levels within the compensation tables only.I refer to a set amount of retard exceeded more than a set number of times.

bob