Jimbob

iTrader: (13)

I have had a few issues of late, so to cut a long story short.

Fitted a Walbro fuel pump.
Changed Lambda as it was knackered (Subaru OEM item).
New plugs and gapped correctly afaik.
Changed coil packs around (all good and all working).
Decatted the downpipe (issue was there before that).
Removed CAT Fire Sensor (today).
Changed a dodgy injector for a good one.

Right whats happening is car pulls well to 3800/4000rpm, after 4000 the revs drop as if I`ve turned the engine off, the boost goes to 5-10psi. And where I was before getting a CAT on Fire light she now pops out the back rather loudly. She`s been doing this for a small while now and I`d assumed it was from the lamda breakup sending bits into the cat, so igniting fuel making the fire sensor come on and cut the power. Under load or cruising as soon as I get to 3800-4000 she hesitates pops and bangs and generally acts as it shes swallowed a small mammal.

The car is running standard ECU (Z4) standard boost control, standard airbox, everything connected as she should be ie OEM.

So my only thoughts are either the MAF is misreading, other than that I`m at a loss.

I`m a little perplexed to be quite honest, any help on a diagnosis??

Jimbob

iTrader: (13)

Bump help needed.

Bobfrog

Found this in the welsh section earlier: https://www.scoobynet.com/wales-26/8...-problems.html

I have manual boost controller for the Ka you can borrow to test butt!

Jimbob

iTrader: (13)

Cheers Paul.

Will have a look tomorrow lol.

Jimbob

iTrader: (13)

Done a quick ECU check and threw up codes 44 and 45.
44 Turbocharging Pressure Control Signal
45 Pressure Sensor

So yet another thing to change lol.

Bobfrog

Hopefully it'll be the last thing to sort out

I'm in tonight but have no car (making way for the new one I bought lastnight lol) so come over if you want to pick up the boost controller as I won't be able to drop it up until Thursday night

saiklon

This also sounds like a speedometer signal issue - though that happens at 4500rpm. An ECU reset will cure a speedo issue for a short while so it's a way of eliminating that problem.

Glowplug

iTrader: (8)

If it will not drive over 4-4500rpm then it could well be in limp mode.
Try resetting the ECU, go for a drive, then do another fault check

The cat on fire (EGT) sensor is no longer required as you have no cat. It will show the light if left connected due to the increased temp caused by the decat.

The pops and bangs from the exhaust are caused by the decat, and are expected. Are you running a VTA DV aswell?

Bobfrog

He is running a VTA DV, when it happens the boost drops right off and the car feels like you've put the brakes on then lurches forward again by which time you're then back under 4-4.5k revs and it runs ok, it happens at the same revs even if you're hard on the throttle or trying to ease it through

Glowplug

iTrader: (8)

Yeah, it's in limp mode, get the ECU reset here.
The VTA DV is also contributing to the pops and bangs as they cause the car to over fuel

Bobfrog

With the boost controller bypassed (feed from turbo put into the actuator) it still pops and farts but never sees more than 6psi which is what I assume the actuator is set at mechanically. We removed the VTA DV it now doesn't lurch so much but the problem is still there, the MAF was cleaned out with some electrical contact cleaner too.

There's a "woosh" sound like there's a big boost leak but we checked the hoses and vac feeds etc with a rev while stationary, the turbo doesn't appear to be surging, it feels and sounds like it's spooling up as you'd expect

** edit to say that Jim reset the ECU as per the instructions too

Jimbob

iTrader: (13)

Was advised on Scoobynet to reset the ECU, so I did.
This is a quote form my mate who was giving me a hand today.
Yeah as said above the standard boost controller was by passed by putting the vac hose form the turbo straight to the waste gate actuator.
Took it for a spin and hessitation, and felt as if the power was fluctuating, gives a massive pop and cuts the power almost peeling your face off the screen.

So we removed the vacuum hose to the VTA DV and closed it off, this made the pops and major hesitation less violent, but still keeps it there.

When cold she struggles to start occasionally and gets better when warm, saying that when cold she hesitates at 3k and clears to 4k where she hesitates again.

Driving home now and on the M4 cruising at 65 and was watching boost gauge, was -4psi constant but felt as if she was missing, also gave an occasional pop when cruising. Theres a sensor there thats not happy, or something electrical thats not right but as for what it is I`m stumped.

This is doing my head in now, as this Impreza is starting to look more like a pile of parts again, than a fully working car.

Glowplug

iTrader: (8)

Have you done another fault check yet, or did the CEL flash a code during the reset?

edit: do you still get the 'whooosh' sound when running direct from turbo to wastegate?

Bobfrog

I don't know exactly which fault check Jim did but the CEL was flashing every second during a test/reset but Jim will confirm what exactly he was doing

The woosh is present when the acutator is fed from the turbo directly and when it's fed through the boost valve, Jim has a spare actuator which I believe he wants to try out incase it's weak

Is the boost controller linked to the ECU or does it control boost in a standalone fashion and the ECU see's only MAP sensor?

Is the ECU mapped boost/rpm or boost/tps?, does it use an air temp sensor? I'm wondering if it's an issue with a sensor not directly connected to the turbo setup that we're overlooking

Jimbob

iTrader: (13)

Yeah, best way I can describe it having just come from it is feels flat as hell then gives some oomph, then off, then on. And thats not accelerating hard, just keeping up with traffic. Pootling in 4th 45ish its like if I`m towing someone in that it holds back and then feel free, then held back again.

There is a whoosh sound same sound as when letting off the throttle, its DEFFO not turbo spool as before she was quiet but an unmistakeable quiet whistle, this is as if there air escaping. Having checked the intake as much as you can on a hot engine on the side of the road at 9pm, and no obvious leaks. And everything is attached and not blown off as far as I can see.

Glowplug

iTrader: (8)

No idea on that one mate.

Sounds like an air leak. 9 pm on the road side is no way to check for leaks. You need to check them 'all' small and large, there are pipes under the IC which can and do split. Check all the jubilee clips too I would do all this before changing the wastegate. Do another fault check, see what it spits up.

Jimbob

iTrader: (13)

Will pop out when its not raining lol.

But there is one pipe on my intercooler, I have the early slanty type.
Had the intercooler off since this has been occurring and everything seems as it should. What a are the two sensors by the boost controller, one is a MAP sensor, unsure on the other.
Also when cold shes a bugger to start, sometimes taking 3 attempts to fire and keep going.

TBH I need her looked at by someone who knows their schizzle as they`d diagnose the issue nearly straight away as these aren`t the most complicated of engines and ECU`s, just I`ve not ad the experience or knowledge on the ecu/boost side yet.

Glowplug

iTrader: (8)

Two pipes on your I/C me thinks, one hard pipe from the rear that runs under and the large front inlet pipe. The hard pipe can split/crack, check the flexi bit.




In the middle is the Boost Control Solenoid, on the left is the MAP Sensor and on top is the Pressure Exchange Unit. The latter 2 are what fault code 45 refers to in post #5. Which is why i asked you to do another fault check, to see if the codes have cleared or re-occured since the reset. These faults can be thrown up by other causes and to replace either or both of these items my be a waste of time. Obviously, if they show agin then they must be considered stong contenders.

Jimbob

iTrader: (13)

Back in 5 lol.

Bobfrog

We can make a boost leak detector with that adjustable fuel pressure regulator I gave you, it goes in a plenum vac pipe (it's the closest to the chambers i.e. whats going into the engine), we put some pressure down the vac line coming off the turbo (i.e. the start of the boost system) and see if she holds the pressure, all we need is something to deliver the compressed gas and listen for a leak

Jimbob

iTrader: (13)

Right NO codes BUT Engine Check light flashes every second or so.
Video below.

Glowplug

iTrader: (8)

OK, that looks good

Above you say, 'issue was there before that' (changing D/P). Can you remember what you changed just before it started f'ing about?

Jimbob

iTrader: (13)

Where do I start, there is a new engine lol.

But got engine running first off and there was a missfire, swapped coil packs and plugs and still there turned out to be injector plug, so have swapped injector.
Then she went like a rocket boosting to 17psi and pulling hard just using loads of fuel.

Changed the turbo to intercooler pipe, as mine was split. Used the seal that came with the intercooler, its a hard plastic pipe so if it had snapped would have been easy to see. Will recheck anyways.

Then was driving to a local car show, and as I put power down there was the cat fire sensor coming on and nearly went through the windscreen. This was along with horrid fuel consumption (still bad) so had been parked up till I got a new lambda sensor.

Since that day the cat fire sensor had been coming on with all the faults listed above.
Plus not sure she`s ever run right, as I bought her with a dead engine, and bought a forged replacement out of a running car form here.

Only thing I can think of is the previous owner had a heater matrix explode so covering the passenger foot well (we know what lives there), then his h/g went, when rebuilt it threw a rod after 2-3 miles.
Could this be the root cause of all my issues??

Glowplug

iTrader: (8)

What you thinking, a drowned ECU?

GazJenno

That flashing check engine light occurs if the green or black plugs are still connected together doesnt it... I cant remember exactly but I think both black and green connectors should be unplugged from each other during normal running? Maybe someone can confirm... Im just trying to put another idea up there for you?

Gaz

GazJenno

http://www.saxonfields.freeserve.co....iag%20Page.htm

Glowplug

iTrader: (8)

Now i know it's a full transplant job, i think it will be almost impossible to diagnose on a forum.
The best suggestion i can make now, is to wheel her in to some where that knows scoobs and get them to have a look. Sorry

Jimbob

iTrader: (13)

Yeah thats what I`m thinking too, as someone who knows their schizzle will be able to havea fiddle for a bit and get to the bottom of it.

Bobfrog

Have you done any tinkering tonight?

Jimbob

iTrader: (13)

Yes and found two definite culprits.

I started her earlier and I felt she was deffo missing, so fiddled with the usual passenger side injector plugs (previous issues), did nothing.
Moved to injector under the expansion tank thing, and low and behold thats one problem. Gonna take the tank off tomorrow and swap the injector to a different one, may even change the other as I`m there.
When I fiddled with it it ran for 10 mins like normal and went like she did before.


Also went and got my spare TD05 from the garage and checks actuator rods side by side, and the arm on the one fitted moved easily (too easily), so I think the diaphragm has gone so I`m losing boost through the wastegate.

So will change the actuator tomorrow making sure shes adjusted properly, and then put the boost controller back on, then change the injectors. As I think my issues are a combination of those two. Once I`ve done that and there is something else then I`m well and truly stumped (for now lol).