marklemac

Set off this morning for my normal days worth of visits to clients.

Everything fine.

On my second stop I was onsite for around 3 hrs. when I got back into my car I poodled off and then joined the M27. Join the motorway and then plant it in 3/4/5/6. Strange, not a quick as it normally is. Whilst in 6th (3k) I floor it - boost gauge reads 9 psi max - normally it will peek at 21.

UG - i think to myself. Leave the M27 and find a quiet stretch of road and try flooring it again in 3/4th, still won't go more than 9psi.

S**T I'm thinking now...

So, I gave it a few more miles and found an appropriate layby to pull into.

Turned off the engine and allowed it to rest for a minute. Started it back up and pulled off. Into 2nd, foot to the floor - WHEY HEY - full power back, into 3rd, 21psi peek is back.

So, what happened ? Did the ECU get a fault and pull back the boost ?

Any comments would be appreciated.

I've now ordered the Deltadash software so can't wait for that to be plugged in so I can see what is going on..

EMS

For some reason the ECU reduces boost, most likely it´s because of knock. If you switch off the ignition and on again, there is a reset. However you should have a fault code stored in the ECU, which can be read with the Delta Dash or the Subaru Select Monitor.

Mark.

dowser

If it's knock related, there's no fault code. The multiplier is reset.....to '1'

Richard

DJB

I've noticed variable power delivery from my STi7 PPP - this was so noticeable that I went back to the dealer to have it checked. Everything was ok - boost normal for PPP and no fault codes.

I have noticed that a period of gentle driving leads to limited boost when you do need the power, especially if accelerating in higher gears (ie 4th, 5th, 6th). Typically you're stuck in congested trafic and you then say pull onto a motorway slip road and floor it - I find in such circumstances, it does not pull as well as it should (I don't have a boost gauge so don't know about peak boost). Alternatively if you accelerate from zero in first through the gears, it always pulls well. Dealer mechanic mentioned something about ECU learning your driving style and adjusting accordingly - find it hard to believe that the ECU will limit boost just because you're not gunning it all the time.

D.

marklemac

Well its just happended to me again.

Left a clients at 8.30pm (outside temp 5 degrees).

Gave it a real hard drive on the way home, full boosting fine.

Overtook several cars and then eased off. Went to boot it again and the car was holding back. Boost guage indicates 9-10psi (normally up near 20psi).

Tried several low rpm runs but no boost above 10psi.

Drove like this for about 10 mins and then pulled over and turned off the engine.

Restarted, got straight back onto a dual carriageway and full boost is there, no problem.

I do have Delta Dash. Is there anything I can look for if I plug it in tomorrow ?

What gives ?

Bloody annoying. Only the 2nd time it has occured....

RT

I had it too on a Bugeye JDM STI RA. Happened about 4 times in the 2.5yrs (& 65000km) I've owned the car. Always after about 10mins, it recovers by itself. No fault codes registered, but I did not have the DD on site so I couldn't tell if the AM was "1" when that happened.

I just put it down to poor fuel. Strange thing was, the KL did not show any unusual activity.

JamieMiller

I had a similar problem on my UK MY00. Had it checked out at the dealers and fault cured itself. It came back about 6 months later, same again it cured itself. 3rd time it happened I stopped and popped the bonnet with the engine running and saw that the wastegate was jammed open. Shut it with pliers(carefully). A week later it did it again and cured itself again. I stripped of the heatshield and removed the 2 bolts holding on the wastegate actuator and gave it a good freeing off with WD40. Never had a problem since, told the guys at the dealers and they had never heard of this. Just a suggestion, I put mine down to dirt in the wastegate.

marklemac

Damn it.

It did it again this morning. Gave it a good thrashing down a slip road and all was fine. later I went to overtake and floored it and the boost would only max out to 10psi.

What I also noticed whilst the car is in this state, is that when you put your foot down there is hardly any delay in getting the boost to the 10psi slot, whereas normally the boost would climb nicely....

Anyhow, couldn't pull over as I was on a motorway. Carried on for 20 mins or so and then pulled over. Turned the car off and back on, and set off. Put my foot down and still only boosting 10psi. F***

Carried on and stopped at my first job. 2 hrs later got back in the car and all was fine, full boost was back.

Took onboard the comments about the perhaps stuck wastegate, so I went to my dealer as I was passing and spoke to the mechanic there.

He said that the wastegate would not be causing this problem and most likely the PPP ECU was up the creak and maybe my MAF sensor too.

So, they are going to look at this in two weeks time when my car is in for a new clutch and flywheel under warranty, and also getting the rear suspension knocking/clunking sorted too.

They said they would send my ecu back to Prodrive to get a new map downloaded onto it.

Anybody care to comment ?

I'm worried that next time I go to pull out and overtake the power will be missing...

russell hayward

My 7 PPP (piggyback version) did this, and nobody (incl Prodrive) really pinned down the problem.

In the end, thanks to my Dealer, the ECU was changed to the later remapped version, and it didn't do it again.

marklemac

fingers crossed. I do believe mine is a ecutek'd PPP, but obviously there is no guarantees. Mine was done in April 2003 just as they were starting to use the new mapped version.

G00ner

'Knocking suspension'

Don't hold your breathe while waiting for those muppets at Sparshatts to get it sorted.

I reported my knocking over 25,000 miles ago and it got worse and worse to the point where I sold the car just to get rid of it. [img]images/smilies/mad.gif[/img]

RT

10psi or approx 0.5bar is what you will get if the boost solenoid did not pulse. It is the "safe mode" when the ECU turns off the solenoid. It is entirely possible that a jammed wastegate results in the same thing.

Those who can, see Steve Done's reply to my post on the ECUTEK forums. The last time this happened to me, I did notice slightly retarded timing (on my SECS display) with WOT. 5 mins later, boost was cut to 0.5bar.

But few minutes after that, everything returned to normal.

dowser

Marklemac,

If you have DeltaDash, check the 'advance multiplier' data point. This shows the ECU's willingness to advance timing. It should really be at 16 (but I've not seen a piggy-back PPP car, so don't know whether this screws with things somewhat). It will read 8 after an ECU reset, and slowly increase back to 16 after a few miles (why the car feels flat after a reset).

If your problem is intermittent, then I'd point a finger at petrol quality, but it would also be worth comparing MAF voltage outputs compared to a car of similar spec. I assume there are no stored fault codes?

Richard

marklemac

dowser,

I will connect it up later when I return and see.

I must admit, I have never really been able to get the AIM higher than 13.

I always use optimax.

I'll check the readings and report back.

DJB

Is this a temperature problem? The ECUtek PPP will limit the boost peak if the engine is too cold (anything short of full operating temperature) or if the charge is too hot (stop/start driving allowing heat soak to occur).

D.

marklemac

Right, I connected up the delta dash last night. No fault codes found.

Did a ECU reset and went for a drive, then several hard runs, and logged the files ,as it is hard work looking at the laptop screen whilst driving :-)

When I looked at the files, my AIM was still only 8. not good.

I can't believe that every tank of fuel I have is 'bad'.

I'm out and about today so I am going to do another reset and log every hard run I do today...

dowser

Every time you reset it, it will start again from an IAM of 8. Best is to leave it to see if it's just a slow learner

But if you're never seeing an IAM of 16, then this is the problem I guess (but you should still confirm with another PPP owner whether his is at 16).

An IAM of 13 indicates the ECU is not that happy to advance ignition. Meaning there's a problem elsewhere - no idea where though! Maybe worth comparing MAF voltages between yours and another PPP car (running the same boost) - it could be as simple as an under reading sensors making things too 'tinkly'.

Whatever, get it fixed before it goes bang - your loss of boost is done to stop this happening.....

Richard

marklemac

did some runs this morning, and now the AIM is 13.

Nearly out of fuel now, so I am actually tempted to put in Esso SUL rather than Optimax which is all I have been running on for several months, just to see if there is any logged difference between the 2.

Although I have the delta dash, I'm certainly no expert in this field so I am having trouble understanding what it is actually telling me anyway. ie knock,timing etc..

shodan

I had the same problem twice with my STi7 (no PPP). I was told from different sources that it's probably fuel quality.
Change your gas station

Chungster

I hope its nothing to do with the HKS SSQV Mark.



But can't be really as you experienced this problem BEFORE you had it fitted also.

Strange one.

marklemac

Chungster,

Yeah had it before the HKS was fitted so I know its not that. I've been logging with the delta dash and just don't seem to get a high AIM figure.

This was also apparent went it first got dynoed at PE last May, and Mutant Matt spoke to Simon from Prodrive who was there and he said 'bad fuel' - seems to be the easy answer.

As my dealers mechanic seems to think it could be the ECU, I will be pushing for them to send it back to Prodrive for a another map to be loaded onto it.

marklemac

**Update**

Took my car back to the dealer and left it with them for a few days. When I went back to collect it I was told that the ECU was sent back to Prodrive for a new map to be downloaded onto it, but actually Prodrive sent my dealer a new ECU with a new map on it.

Collected the car 2-3 weeks ago and it drives like a new car - wicked. Pulls much harder now in all gears.

Anyhow, today whilst giving it a bit of booty in 5th, I eased off the throttle and back on again full throttle and the car stuck to 10psi again. Again, no matter how many times I put foot to the floor, 10psi was the max.

Then all of a sudden I did full throttle again and then the car jumped pass 10psi. Almost felt like something had got stuck. Rest of the journey was fine. Full boost achieved.

So my question is, what could possibly be causing this ? could this be a sticky wastegate ?

I'm at the dealer tomorrow anyway getting my cluncking suspension fixed again so I will mention it again to them.

Pete Croney

The Advance Multiplier can be very reluctant to climb to 16 if you don't get it there almost straight away.

Do not drive the car hard after a reset.

Drive at approx 50%-75% throttle, using between 3000 and 4750rpm up through the gears. You ideally want to hold approx 0.5bar of boost. If the car is driven like this then you should hit 16 in less than a mile.

How the AM works is it acts as a constant on the ignition correction table. If you have a base setting of 18deg and a correction established, by the ECU, of 8.60degs (making a total of 26.6deg) on a multiplier of 16, a multiplier of 12 will give 18 + 6.45 = 24.45 degrees advance. On an STi 7-8; 1 degree difference in advance equates to approx 10lb of torque!!

EMS

Why do I see the last post being from 30 Januari 2004 and on the page before it is shown last post Today by Pete Croney????

I noticed the same thing before.........

Mark.

EMS

Now I am not able to see my own post.......

Can somebody please PM me about the possible cause of this. Answering in this topic won't help me as I can't read it.......

Thanks in advance,

Mark.

Bob Rawle

The ecu is going into limp home, that happens when it sees too much learning retard (not the knock advance that DD reports but the ignition learning which is added or subracted from the base plus compensation times ign multiplier divided by 16) for too long. It means it thinks the car is detting, which is probably true. An advance multiplier of 8 is its start point and is the mean setting (0-16), so if you do an ecu reset thats where it starts, to get it to rise you need to select say 5th and roll the boost up slowly to about 0.8 bar, 0.5 is too low and the ecu will not always get into learning mode, it should kick up to 16 if all is well, however it will not if it sees excessive noise from the knock sensor or if you roll up the boost too aggressively.

I suggests that you have an inherant problem, maybe maf or fuel pump/pressure reg, for sure its unhappy and you should not persist in forcing it to do this as everytime you do IT_COULD_BE_DETTING which is not good of course.

Another reason is it could be purely too rich on fuel, that will cause stutter and high knock sensor output.

Also what plugs and when last changed ... pre-ignition from poor plugs will do it, PFR7B's as a minimum should be used if you are peaking at 1.5 bar, '8's would be better.

Also remove dump valve and have a check in the intercooler for oil, if there is lots deposited then you are probably getting det from the contamination on hard accelleration.

Just some thoughts.

bob

scoobyslut

If its a "gen" PPP unit, get it back to the dealer guys, as there is a re program "fix" available. I had one done "same day " service. they took the ecu off, took it to Subaru Uk, they re mapped it and brought it back and refitted it.
Apparently, some of the ecu's do have a program "glitch" which is only sorted with a full re write.

marklemac

My ECU has already been back to Prodrive and replaced with another ECU with the latest map installed on it with the fix.

Its difficult to explain exactly what the symptoms are when this intermittent problem occurs. It almost feels like the wastegate has stuck partially open.

What normally happens when everything is perfectly fine is that when you put your foot to the floor and accelerate the boost climbs nicely to full boost. You can see this by watching the guage.

When the problem I have has occured, the boost rises to the 10psi problem point very quickly (much more quickly than normal). This suggests to me that perhaps something has stuck partially open hence the rapid rise in boost, but the limiting boost.

When the problem occured 2 days ago, it was exactly as described above, but suddenly when I did accelerate the boost then jumped past its stuck point and achieved full boost. The rest of the journey then was perfectly fine.

Car has done 32k, and was serviced 2k ago (full service).

Not sure what the AIM figure currently is, but if the rain stops later I'll go out and do some Delta Dash recordings to see if everything is fine.

Just to confirm, the problem has occured 5 times in 18 months.

Bob - don't know what plugs are fitted. Standard dealer ones I assume. I'll look behing the dump valve at the weekend.

Bob Rawle

If the ecu has switched off boost control it will rise more quickly as there is no pressure loss from the turbo ie its all directed at the actuator, when the ecu is in control it pwm's the solenoid and a two port bleeds pressure from the turbo as well ... which is the benefit of a three port of course ie reduced loss and better spool. All logical.

BTW if you reset the ecu and don't take it through learning it will stick at 8. It also needs to be taken through fuel learning as well as ignition.

bob

Pete Croney

If you have the latest PPP installed, as opposed to the piggy back, then the problem may be nothing more than the temperature compensation that Prodrive programme in.

This is very taming and the rest at the service station would be more than enough to heat soak the intake. When you set off, the ECU sees very high intake air temperatures and shuts everything down.

Its a safety feature that Prodrive feel is necessary for the STi.