Learning View Snapshots \ Discussions

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Re: Learning View Snapshots \ Discussions

Postby tom_kauf » Sun Jan 12, 2020 7:27 pm

:lol: that's right

Yeah, I've never had mine on the Dyno, apart from checking what power it actually makes.
[Stealth & Speed - Comfort & Practicality]: My 2008 MY09 GT SpecB Wagon - Manual 200,000km
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Re: Learning View Snapshots \ Discussions

Postby bigBADbenny » Sun Jan 12, 2020 7:44 pm

It can be very simple to do the leak check: cap the SFB after the MAF, a yellow metal honey jar will do the trick with the stock clamp.

Apply air pressure at around 1 psi to the BOV ref hose, with eg a bicycle floor pump or any low pressure source, and go nuts with soapy water spray and use a strong torch to peep for bubbles, listen for hissing.

The next level is adding a smoker, look at the Ebay paint can kits for ideas.

My home made kit uses a 12v tyre inflator, garden hose, some fittings including caulking nozzles and a smouldering oily rag in a used paint can.

Smells like an industrial accident but it works :P

Make sure your FPR vac reference hose is hooked up to the inlet manifold, it’s easy enough to miss.
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Re: Learning View Snapshots \ Discussions

Postby Adrian2627 » Sun Jan 12, 2020 7:48 pm

MAF AOK, SFB WTF?
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Re: Learning View Snapshots \ Discussions

Postby bigBADbenny » Sun Jan 12, 2020 7:53 pm

Cmon man, short fat bit, the zig zag pipe post maf. :P

If you block the end of it, you’re sealing the inlet tract, meaning it can be pressurised via the bov ref hose...

Also here’s Matt’s LV explainer:
viewtopic.php?f=56&t=18219&start=240#p290024

There’s also a diagram linked in my tune faq post, link in my signature.
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Re: Learning View Snapshots \ Discussions

Postby Adrian2627 » Sun Jan 12, 2020 7:59 pm

I knew what you were talking about just didn't get the SFB. :roll: Sorry, too much mountain bike not enough car lately.
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Re: Learning View Snapshots \ Discussions

Postby bigBADbenny » Sun Jan 12, 2020 9:43 pm

You might do better posting on SLOGA.
Matt pops up from time to time there..
https://m.facebook.com/groups/1078355455560091
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Re: Learning View Snapshots \ Discussions

Postby Adrian2627 » Mon Jan 13, 2020 8:47 am

Cheers Ben
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Re: Learning View Snapshots \ Discussions

Postby NAB903 » Thu Apr 30, 2020 2:02 am

Hi,

I've just downloaded BTSSM and am completely new to logging, just downloaded it to get a bit of an insight to what was happening. Might have got a little too much because now I have to learn what it all means.

Not sure if its relevent but I have recently reset the ECU, these values are from roughly after two hours worth of driving after the ECU was reset.

In the LV I have been seeing relatively large negative numbers for fuel correction (two examples included). Would this indicate an intake leak somewhere?

BtSsm_LV_20200428_1223.png
BtSsm_LV_20200428_1223.png (48.08 KiB) Viewed 726 times

BtSsm_LV_20200428_1233.png
BtSsm_LV_20200428_1233.png (47.61 KiB) Viewed 726 times


Everytime I go for a drive (max 30 mins) I get a few knock warnings like the one below, low RPM, negative boost and around -2 FKC. Should I be concerend about this as from what I've read some people say its just false knock and others seem to think it may be more serious.

KNOCK DETECTED at 2020-04-28 12:19:30 PM
AFR: 14.5
AFR (lambda): 0.98
Battery (V): 12.3
Boost (psi): -3.20
Boost Target (psi): -3.1
Closed loop: 1
Coolant (degC): 90pr
FKC (deg): -1.41
FLKC (deg): 0.00
Fuel correct (%): -7.4
Fuel learn (%): -1.81
IAM: 1.000
Injector PW (ms): 4.9
Intake (degC): 25
Load (g/rev): 0.81
MAF (g/s): 36.76
MAF (V): 2.50
Misfire cyl 1: 0
Misfire cyl 2: 0
Misfire cyl 3: 0
Misfire cyl 4: 0
RPM: 2723
Speed (kmh): 61.0
Throttle pedal (%): 19.6
Throttle plate (%): 17.6
Timing (deg): 26.0
Turbo WGDC (%): 0.0
VVT int L (deg): 38
VVT int R (deg): 38
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Re: Learning View Snapshots \ Discussions

Postby bigBADbenny » Thu Apr 30, 2020 6:26 am

What year is the car?

The fuel corrections are at idle and the upper rpm range.
To me, this suggests a dynamic leak at full boost eg throttlebody hose gasket.
Same issue for idle, or the latter could be related to an injector issue, if prefl.

With the knock alert function, it’s only an issue if the car is under load.
If you want to use that function, its best to set the alert threshold lower.
Start with -3 and adjust accordingly till you get less false positives.
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Re: Learning View Snapshots \ Discussions

Postby NAB903 » Thu Apr 30, 2020 1:03 pm

Its a 2008 model year.

yea will adjust the alert threshhold, just wanted to check I wasn't ignoring real knock.

How would I go about testing/ fixing the leaks?
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Re: Learning View Snapshots \ Discussions

Postby bigBADbenny » Thu Apr 30, 2020 7:35 pm

Basic checks.

Get the cars obdii port scanned with a scan tool to check for DTC’s aka CEL’s, both current and historic.

Google the codes with make, model and engine keywords.

DTC codes have diagnostic trees in your cars FSM, you can use this info to perform basic troubleshooting in conjunction with info on eg this forum.

Use a google site search with your relevant keywords to search. Eg:
“site:www.forum.liberty.asn.au keyword keywords”

In the google search bar.

More advanced logging and learning view can be done with BtSsm or Romraider.

Log avcs vvt angles with Btssm or Romraider at 1700-2000rpm in neutral and in gear on the freeway, look for vvt angle oscillation, lag or inactivity.
If either issue is revealed, swap avcs oil control solenoid side to side to see if the issue follows the affected solenoid.
If so, replace both ocv solenoids.
If the issue doesn’t follow, check the ocv oil supply banjo bolts for blocked screens.
Very rarely, an avcs cam gear may be jammed with debris or via incorrect installation, usually in this instance it will be locked at a particular angle as revealed by logging.

For dual avcs prefl 2.0t, check if the exhaust avcs solenoids are leaking, the loom can suck oil all the way back to the ecu plug, causing multiple issues.

Log per cylinder misfires.
If misfiring, check spark plug condition and swap around coil pack on the affected cylinder to check if the fault is cylinder or coil pack related, or coil pack loom plug related (usually broken plug clip).

Get an LV (learning view) whilst you’re at it.
LV will reveal inlet leaks, IAM (low IAM = failsafe mode).

Pressure test inlet tract with smoke or dilute detergent bubbles from a trigger spray bottle.

The most basic inlet pressure test is to get someone to rev the car in neutral, whilst you spray the bov, tmic etc with soapy water, looking for air leaks as the car will boost from vacuum to 0psi.

From there, block off the entry of the short fat bit (post maf) and apply any type of low pressure (breath, bike pump etc) car off, spray soapy water or listen for hissing.

On GT’s it’s possible to remove the vacuum hose at the brake booster and blow breath or use compressed air (1-2 psi regulated) past the one way valve. Note the inlet pipe must be blocked, post maf.

From there add smoke to the air starting at 1psi, either way have a strong torch handy for inspection.

Bear in mind to continue the inlet pressure testing after each leak is found.

Also check if your fpr is hooked up to the lhs rear inlet manifold runner. Symptom: backfire and or stumbles under boost.

Gently cleaning the maf is a good idea, use crc maf cleaner on both the inlet temp sensor directly, and the maf wire indirectly via the adjacent air tube.
Be sure to carefully reseat the maf using a little grease to make sure the maf o ring is not pinched. Blow out or replace the air filter at the same time.

In addition to the stock turbo inlet pipe rotting due to accumulated blow by where it meets the turbo,
the stock intercooler to throttlebody pipe is a known issue due to its gasket design at the outlet to the throttlebody.
Inspect, use a quality t-bolt clamp/s eg murray or oetiker stepless, and preferably upgrade to a silicone TB hose eg AVO or Kobe.

Other basic sanity checks are related, visual inspection with a strong torch and inspection mirror of all head breather hoses, boost control and fuel purge hoses, their originating connections, joins and return to the turbo inlet pipe. With age and miles, these pipes and hoses can harden and crack, usually where the fault can’t be seen, eg on the lower side (gravity) or engine side (more heat).

Also if removing the top mount intercooler, pull the pcv at the rear of the inlet manifold, inspect, clean or replace it.

Since you recently had the in tank fuel filter changed, there’s also the possibility of an incorrect reinstallation, usually related to missing, pinched o-rings or not using double o-rings on an aftermarket fuel pump outlet.
If inspecting the bucket and filter assembly, be sure to check the loom connection plug on top of the assy for burnt or corroded pins.
This check would have also been performed during your recent recall/inspection.

H6
Get Btssm and log avcs and vvl angles, per cylinder misfires, neutral position and clutch sensors, make an LV as well.
Visually inspect the oil pressure sensor/s for leakage.
Pressure test inlet tract post maf for vacuum leaks.
Clean the maf, directly on the inlet temp sensor, indirectly for the maf wire, taking care not to pinch the o ring on reinstalling.
Blow out or replace the air filter at the same time.
Faulty brake lights or non resistor led tails can induce failsafe mode on some models, as can vdc issues related to the steering sensor in the clockspring.

H6 avcs & vvl:
Because just like gen4 turbo avcs and davcs,
H6 avcs and vvl are a self calibrating system using the crank and cam position sensors, plus the vvl oil pressure sensor.
Over time, the avcs solenoids get out of whack, the ecu tries to overdrive the lagging solenoid resulting in vvt angle oscillation or inactivity.
The vvl system is apparently more reliable but still subject to wear and tear especially as regards the dedicated oil pressure sensor adjacent the engine oil pressure sensor.
Thus logging is the key to verifying the fault if any.


Inlet pressure test:

Get an old empty paint can, some garden hose, silicone caulking nozzles and a step drill.

The nozzles can work as low pressure fittings.

Tyre valves with the valve removed & bicycle pump hoses also work well.

Run 2 lengths of hose to and from the paint can lid.

Insert one end into air line, reg set to 1 psi.

Insert other end into bov ref hose.

Plug the short fat bit with a jam jar lid, it’s around 2” diameter iirc.

Get a rag with some oil on it, set it on fire so the oil smokes, or use a 12v vape element and fluid connected to your battery.

Drop the rag in the can whilst it’s smouldering and seal the lid.

Open reg, use a very strong torch to spot the smoke.

Do this and or use soapy water spray/bubbles.

Also listen for hissing.

Any hoses that get blow by (most of them) can rot from oil contamination, usually on the underside from oil pooling.

Or they can crack from being near a heat source eg the engine, so you really need to check them in a 360’ fashion.
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Re: Learning View Snapshots \ Discussions

Postby Yowie » Thu Apr 30, 2020 9:02 pm

Great diagnostic list.

Very rarely, an avcs cam gear may be jammed with debris or via incorrect installation, usually in this instance it will be locked at a particular angle as revealed by logging.


In the case of my wife's car (with EJ25), the cam gear was bad and replacing it fixed an issue of intermittent lack of power.

Mechanics' diagnostic tools showed perfect function (due to reading the request signal rather than the actual cam position) but the laptop of a universally popular tuner showed that cam flopping around all over the place.
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Re: Learning View Snapshots \ Discussions

Postby bigBADbenny » Fri May 01, 2020 11:09 am

Interesting, are you sure it was the cam gear and not the ocv that was replaced?
If so (cam gear) do you have a log showing the behaviour under fault conditions?

Iirc one of the first threads on the subject (on LGT) was a cam gear with debris lodged inside, the fault condition was zero or max angle only, iirc.

Here’s the full avcs faq, please help with any additional info...
Gotta add the H6 specifics lol.

AVCS checks.

Here’s my incrementally updated AVCS diagnosis guide: logging is the key.

Consider an AVCS check as part of any health check for your car, especially if you experience a noticeable stumble or hesitantcy under acceleration.

AVCS, active valve control system is Subaru’s implementation of variable valve timing (VVT) for either inlet cams only (single avcs, SAVCS) or both inlet and exhaust cams (dual AVCS, DAVCS, also known as quad AVCS).

The system uses signals from the cam and crankshaft sensors, and oil pressure to control the variable cam angles. Electronic solenoids are opened and closed by the ecu to vary the amount of oil being flowed into the cam gear thus varying the VVT angles according to self calibration of the system and specific load and rpm tables in the tune.

Therefore the loom, plugs, cam and crank sensors may also be considered for inspection. Occasionally built up swarf or sludge on the cam sensors has been seen to cause AVCS issues. This is fairly obvious in logging as a broken up cam VVT angle signal or actual signal dropouts.

However, eg the cam sensors are quite hard to access and more commonly the issue is caused by AVCS OCV or cam gear issues.

As regards GR STi, there was an OCV part number update around 2010, but regardless of your car always make sure your OCV part numbers match your heads, ECU, model etc, eg via a VIN parts search.

The following is generally for cam positions over CEL’s (check engine lights) aka DTC’s (diagnostic trouble codes) P0011 &/or P0021.

Log AVCS VVT left and right angles with Btssm or Romraider at 1700-2000rpm in neutral and in gear on the freeway, look for VVT angle delta, oscillation, lag or inactivity.

If you don’t have SSM logging, one failing AVCS OCV can sometimes be diagnosed by idling a car in neutral til warm, then vary the rpms very slowly between idle and around 2000rpm, pausing and holding certain revs for a minute or so. This can trigger the fault mode on one AVCS bank, causing a stumble or inability to hold the desired rpm. I have tested this on my single AVCS GT-B, not sure if it works for dual AVCS issues.

My theory is that slight differences in the left and right AVCS oil feed pressures, combined with the self calibrating nature of the AVCS system cause one side, usually the LHS, to become overdriven and eventually fail.

The beginnings of this failure is seen as left to right angle lag.

The intermediate stage is one side wildly oscillating whilst the other side operates correctly.

The terminal stage is one side becomes inactive at which point the AVCS system deactivates completely.

All stages can be encountered independently and without triggering a cel.
Meaning taking a look at AVCS operation should be considered a part of regular maintenance and health checks.

If either issue is revealed, swap AVCS oil control solenoid side to side to see if the issue follows the affected solenoid.
If so, replace both OCV solenoids.

If the issue doesn’t follow, check the OCV oil supply banjo bolts for blocked screens. The filters can be very deep in the banjo bolt hole and or broken up. Use a sharp toothpick to fish them out. The specific banjo bolts that contain filters have a raised nipple on the bolt head. The filters can be deep inside the head, try fishing it out with a toothpick (push in, pull out) or, if the filter is broken up, use straight fine tweezers, or create a vacuum venturi by blowing compressed air across the bolt hole. The difficult banjo bolts to access on a complete engine is the one behind the LHS timing cover. Online guides have shown that extracting this banjo bolt is possible if the nipple on the bolt end is filed down and the cam cover is gently pryed with a bar, otherwise its easy with the timing gear off for service.

Very rarely, an AVCS cam gear may be jammed with debris, or via incorrect installation, usually in this instance it will be locked at a particular angle as revealed by logging.

Go for the easiest tests (logging) first, if all results are negative, eg you have AVCS inactivity which does NOT follow the OCV side to side swap, pull the crank and cam sensors to check for contamination by metal particles on the cam sensor face or check for oil supply issues at the banjo bolt filters. Generally, the banjo bolts that contain filters are the bolts with a raised nipple on the head.

My solution for a failed OCV is to start with installing two new AVCS solenoids and then to periodically swap them side to side (eg at 50k mi) or when significant angle lag becomes noticeable in logging.

The issue seems less prevalent in prefl libs, perhaps this is due to the turbo & avcs oil feed being located on the right rear head, and the exhaust avcs solenoids being fed directly from the heads via the avcs ocv manifolds, however:

For dual AVCS prefl 2.0t, check if the exhaust AVCS solenoid O-rings (#1 in 5 in the diagram below) or the exhaust AVCS oil control solenoid manifold gaskets (#17 below) are leaking, the loom can suck oil all the way back to the ecu plug, causing multiple issues.

Log per cylinder misfires.
If misfiring, check spark plug condition and swap around coil pack on the affected cylinder to check if the fault is cylinder or coil pack related, or coil pack loom plug related (usually broken plug clip).

Get an LV (learning view) whilst you’re at it.
LV will reveal inlet leaks, IAM (low IAM = failsafe mode). Regularly health check your car, including reading the spark plugs, and doing inlet pressure tests.

Its always a good idea to consult your cars FSM workshop manual to check the actual diagnostic procedures.

I’m always updating the info here as I do more research. Some items I need to clear up below.

Can skipped or stretched timing cause an AVCS CEL or issue?

What are the causes of gradual VVT angle lag, that eventually leads to one bank failing completely?

Let me know if you have any information to add!
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Re: Learning View Snapshots \ Discussions

Postby Yowie » Fri May 01, 2020 9:12 pm

Interesting, are you sure it was the cam gear and not the ocv that was replaced?
If so (cam gear) do you have a log showing the behaviour under fault conditions?


Pretty sure it was the cam gear. That's what the mechanic replaced to fix the problem. No copy of a log, but I watched a trace of the two inlet cams on Matt's laptop screen. The operational bank was a predictable "sine curve" type trace while the faulty one flopped around with no pattern.
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Re: Learning View Snapshots \ Discussions

Postby bigBADbenny » Mon May 04, 2020 1:59 pm

If you still have the gear (unlikely...) it would be interesting to tear it down ;)
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