Glowplug

iTrader: (8)

Wastegate is 0.5bar iirc.


I've just removed my Forge vta after 2 years of faultless service, imho they are the best vta.

Yes, 0.5 will be wastegate pressure then, as that is what it is falling back too. Have you tried cleaning the Pressure Exchange Solenoid? Thats the unit on top of the BCS with the black cylindrical filter on one end and a small hose on the other. Pull the hose and the black filter off and flush with carb cleaner.


Any chance you could try some V-Power? See Peters thread: https://www.scoobynet.com/scoobynet-...d-at-last.html
If the ECU is sensing knock due to low RON/octane it will pull the boost.

I very much doubt it, although stranger things have happened.

More likely to be a sensor on the way out. Have you done a fault check recently.

Jaywalker

If the wastegate pressure is 0.5 bar then am I right in saying its not the wastegate lol,

I have cleaned the PES my old one that is, tested it then I bought a second hand one and I haven't cleaned that one yet but with both PES's the symptoms have stayed the same, I will clean the second one aswell cant do no harm but It's unlikely for 2 PES's to be faulty but not unheard of lol

Damm I have just filled up but I will give anything a try or for now I could just get some octane booster for this tank of fuel and when it runs out I'll try v-power, It does sound interesting peters thread, where can I get a temp knock link to check if mines knocking or how would I check for knock lol Could I use my multi meter to check voltage while I'm driving lol

just done a fault check still coming up nothing

Jamz_

iTrader: (12)

Well it could be the wastegate... if the wastegate is staying open, the car will only produce 0.5bar pressure... i too had this problem, and it turned out that the waste gate bar from the actuator had fallen off...

Have you tried removing the bar off your wastegate/actuator and tried moving the wastegate by hand see if it gets stuck? Sounds to me as if your wastegate is getting stuck in the open posision maybe?

Glowplug

iTrader: (8)

Go with Jamz post. It only takes 2 mins to check the w/g arm.

Yes, seems very unlikely.

A drop or two of NF would indeed rule out poor quality fuel.

The only way i know of, is with a Knock Link or by using SSM1/RomRaider and logging the behaviour/activity of your engine.

You could PM Peter and ask him how he did it, he is a very nice fella and i'm sure he will not mind helping you out.

So we are still geussing, educated or otherwise.

Jaywalker

Just got some octane booster and put that in and I'll give a good blast later to see if it helps but before I go out I'll give the watsegate arm a check might even give the arm a spray with some WD40,

Thanks for the help guy's and I will let you know how I get on, you've given me a few things to keep me occupied for a while.

Jaywalker

No luck as yet I checked the waste gate arm all moves freely, Put the octane booster in a couple of days ago still the same,

I got a question sorry if it sounds stupid, How exactly does the ECU control the boost?

Correct me if I'm wrong, From the nipple on the turbo the boosted air goes to the BCS, The ECU reads what boost its getting and either lets the air through to the wastegate or not depending on the pressure, So if the pressure is 0.6.99999bar or under the flow of boosted air is restricted by the BCS so to allow pressure to build up, If the pressure is 0.7 or above the BCS lets the air through to the wastegate and regulates so the boost stays at 0.7bar.

So therefore if the wastegate was faulty and the car and BCS was working perfectly you would'nt know?

If the BCS was opening or staying open allowing the boosted air from the turbo nipple straight through to the actuator then either the BCS is buggered or the ECU is telling the BCS theirs a problem with something and to let the air through thus only achieveing actuator pressure only which is 0.5bar?

So my question is if the actuator was not working properly why would this effect my boost (0.5bar) if the BCS was working properly?

Again I don't know this is true and I'm hoping you will correct me if I'm wrong It's just the way my mind works can't get my head round the purpose of the actuator other than a fail safe incase the BCS fails. I know on my old RST there was no BCS the actuator was my BCS lol

Glowplug

iTrader: (8)

Moves freely, how freely. There should be very little movement really.

Boost is controlled both mechanically(wastegate) and electronically (ECU,BCS,MAP,PES)


That is the 'basic' principal, yes.


If the w/g was to tight and not opening then you will over boost. If the w/g is to loose, you will loose boost.
As i said above, how loose is the actuator arm??


Correct.
Can you hear the BCS clicking away, just a little throttle and it should be audiable, failing that put it in test mode and listen.

Correct again.



As above, boost is achieved by both mechanics and electronics. Thus all parts must be working together correctly to achive optimum performance. If the actuator is slack then it takes less boost to open it and you never make your target. If it is to tight, then it takes more pressure to open it, you then see your target, or overboost.

You have to see the BCS as a 'bleed valve'. What it does is, it bleeds off pressure, away from the actuator. The W/G will feel pressure from the moment it starts to build, the BCS and the ECU know that the W/G is set to 0.5bar, so 'they' let through say 4.75bar and bleed the rest off via the bottom hose of the BCS back to the air intake. Until 'they' sense, say 0.75bar, at which point everything works together to maintain 0.7bar.

However, if say the arm of the actuator is (loose) set to 0.4bar the ECU and BCS cannot know this, hence carry on letting 0.5bar through, so the W/G is constantly open and the boost will never get above W/G pressure.

See this http://www.scoobypedia.co.uk/index.p...urWastegateArm

Jaywalker

Sorry when I say the wastegate arm moves freely I ment to say when I pull on it against the spring it comes out and it goes back in (with a little force) there is no free movement (slack)with the wastegate lol,

Glowplug

iTrader: (8)

Daaam!

Have you tried running with the very bottom hose of the BCS disconnected??

Jamz_

iTrader: (12)

That should make it overboost

Glowplug

iTrader: (8)

Hopefully.

I'm just thinking, if the restictor or its pipe is blocked it my be not make target.

Jamz_

iTrader: (12)

But then that wouldn't explain the symptoms of it working fine for a day or so then just go to 0.5.... would it?

Glowplug

iTrader: (8)

Perhaps if the 'blockage' is on the move??

I'm fast running out of ideas for him to try.

Jaywalker

Right just spent a couple of hours testing the car,

First I connected the green plugs, BCS clicking away happily cleaned it anyway, next cleaned the PES (again),

Then I rev'ed the car up while looking at the actuator arm it came out and went back in again as normal, Next got the air compressor out to check the actuator pressure I used the hose from the BCS, 2 jobs in one hose was ok no air leaks, Set the pressure to 1bar on the compressor the actuator arm came out and it held 1bar then I gradually let the air out until it got down to 0.5bar at which point the actuator arm went back in and it held 0.5bar no problems there,

Next I removed the hose off the nipple on the turbo so no boosted air was going to the BCS the car over boosted as expected so replaced that hose,

Then I removed the hose from the BCS going to the actuator so boosted air was getting to the BCS but not to the actuator again over boosted as expected,

Right next I wound the actuator arm right in as far as it would go in theory making it boost higher, still boosted at 0.5bar,

Then wound the actuator arm all the way out giving me less boost and it boosted to 0.3bar, so this tells me the actuator is working I hope,

Its sounds to me as a result of these tests that the ECU is restricting the boost would that be a valid assumption??

Also what do I check now LOL, I think I might reset the ECU again at least I wont be depressed for a week or 2 lol, Or I might put my MBC back on but I don't want to mask the problem It's doing it for a reason I suppose.

I just had a thought If I remove the hose from the turbo nipple before the BCS and put the air compressor on it IE fooling the BCS with compressed air with the engine running, but can't think what this would prove lol I'll have to think about that one

Glowplug

iTrader: (8)

A well spent couple of hours.

As you are 0.2bar (3psi) under target and in your testing you have found the W/G operating at 0.3bar, again a difference of 0.2bar. Now 0.2bar is not a great deal. Would you feel it during driving??

As it seems a consistant deficit,
could it simply be, your boost gauge is mis-reading??

Jaywalker

No, The boost gauge is not mis-reading the car is like day and night when its running normal 0.7bar its spot on smooth acceleration but when it drops to 0.5bar just gets to 0.5bar and you can physically feel it restricting its self, I mean I nearly got beat away from the traffic lights by a corolla last night you know when 'that the car shouldn't still be next to me moment' lol plus when i put my MBC on it reads fine and also after a reset, the feel of acceleration as i said is like day and night

Glowplug

iTrader: (8)

I think that's a good idea, have a break.

While your at a loose end you could consider this

dan83590

It runs fine with the MBC attached??

Have you tried a new BCS yet?

Jaywalker

Yes it runs fine with a MBC attached, and yes I have tried another BCS in fact I now have 2 BCS, 2 PES, 2 map sensors and 2 knock sensors lol


looks good I will see if i got an extension lead long enough to put the pc in the car lol

Glowplug

iTrader: (8)

It may allow you see the fault/problem.
Yeah that could be an issue.

You will need to make the diagnostic cable first though, as our old Classics are SSMI and not OBDII. Cost you about £20 but will allow you to monitor knock, afr etc so gives you a fairly good view of what is occuring. I'm just looking into converting it to OBDII at the moment.

Jaywalker

what's SSMI and OBDII ? lol some kind of plug type?

how does the plug connect to the ECU would i have to unplug one of the 4 plugs that are already there?

sounds like something I would be interested in had a quick look at the diagrams look a bit French to me lol is there a idiots diagram out there for me lol

f4la k

iTrader: (1)

If youve done all of the above mate, id pull the turbo off. A while back my mate had similar problems and we checked all the above that you've done and it turned out that the wastegate in the exhaust housing was worn and even though the actuator arm was working ok there was sill a small bit of play on the actuall wastegate and when it was making boost there was enough play for it to not seat correct and it was not holding boost.

I know it might not be this, as you have stated that when you do an ecu reset, the car seems to run fine which probably rules this out, but id be defo checking it, just to be 100% certain.
Thers is no loose bolts or anything rattling about near the knock sensor, maybe somethings came slack or something around the inlet manifold thats goin to give a false reading from the knock sensor.
Where abouts are you based...

Jamz_

iTrader: (12)

OBDII is the diagnostics port used in modern cars, but the classic doesn come with this connector... I would be interested to know how you can make a lead to plug a classic into a PC

Glowplug

iTrader: (8)

Subaru Select Monitor 1 and On Board Diagnostics 2. As Jamz says.

Where the blacks and greens are is a yellow SSMI socket.


That is the idiots guide. It is a piece of p1ss mate. Just pm me if you need a hand.

Here you go. I didn't **** about with the pin strip, just soldered wire to wire.

Jaywalker

I will definitely look into this as it could be very helpful,

I just done a ECU reset and the car is fine now 0.7 bar but for how long lol

I'm in the essex area and i will have a good look near the knock sensor tomorrow for loose objects thanks

Jaywalker

Hello again guys it's gone back down to 0.5bar again this evening bugger,

b13 Bat is there a list of parts i need to buy for that lead anywhere, I'm gonna have a go at making one lol

thanks

Jamz_

iTrader: (12)

Jay where abouts are you from?

Glowplug

iTrader: (8)

Yeah here mate. The simple version is good, as i said, i didn't bother with the pin strip, it is far easier to solder wire to wire.

Jaywalker

b13bat thanks

Jamz I'm an Essex boy lol

Jaywalker

That one looks alot easier the the first one i looked at lol the simple one looks like just joining the two connectors together IE usb to the legacy audio harness via soldering lol I can do that lol