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Brendon001

VVTI question Altezza

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Hi guys

So I have an altezza with the 3sge beams, pnp g4 altezza link ecu and greddy tdo4 turbo kit. Was currently running on a turbosmart wastegate actuator with 7psi spring, tuned at 9.3psi for the last 3 years with no issues. (Was never sure how it managed this with no boost control on a 7psi spring but worked perfect) On my last track day the car suddenly dropped to 7psi boost and would not boost higher and felt sluggish. I initially though boost leak etc. Found a few and now passes boost leak test perfect. Fitted a new actuator spring and wired in a link boost solenoid. My tuner on the hub dyno however could not get the car to get up to its previous 172rwkw. even using the new boost solenoid, it could make 9.2psi but has lost around 20rwkw. he then noticed that the car wasnt responding much to timing changes where some runs would start off good and then drop out, or some runs would just not start off good at all even with no changes to the ecu. He was then thinking maybe sensors or vvti solenoids so I have changed all of these and still no change. Could it be a sign the turbo is just wearing out or something to do with my vvti system? turbo has been on for 3 years with around 5 track days and weekend driving 30,000kms. 

I have attached my tune file and a log file for a recent test drive logging the intake and exhaust cam positions and targets and solenoid duty cylces. Also a last question is the DI2 value (where the exhaust cam sensor is wired to) never illuminate green or says on when driving, just stays unlit and OFF. (ie the power steering DI1 will illuminate green and change to ON when turning). 

I have checked all sensor have ground and continuity back to the ecu input pins, and all 3 (crank, intake and exhaust cam sensors all have readings of 1.02 k ohms).Thanks

Thanks

Brendon

Brendon original tune 5.0.3 01-10-16 (after launch control and cold tune start fixed) with boost solenoid settings.pclr

vvt log drive.llg

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Yeah if you were having problems with the VVTI it would end up not tracking well when you overlay target / actual position but it seems fine. 

If AFRs are looking good then I'd think you're getting some sort of misfire or spark issue as next thing to look into.

Otherwise compression test / leakdown test I guess.

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Yeah if you were having problems with the VVTI it would end up not tracking well when you overlay target / actual position but it seems fine. 

If AFRs are looking good then I'd think you're getting some sort of misfire or spark issue as next thing to look into.

Otherwise compression test / leakdown test I guess.

Exactly what i was about to suggest,

Do a compression test , change plugs , check air cleaner etc.

You could also do a leak down test just to double check the health of your engine.

Always a good place to start.

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Hello Brendon001. Looks like the vvt control settings are a little off from where they should be. Check the offset for the intake cam. Once you get that setup, go back and make sure the solenoid itself is actually functioning properly. Sometimes these tend to get gummed up with bad oil and contaminants. Looking at the VVT exhaust axis setup, you are going past the manifold absolute pressure setting of atmosphere because you are making 9psi. This will stay with the last value but I like to know the tables correlate to what the engine is doing.  The Duty cycle is kinda all over the place when looking at the log as well. Go back and correct these things making sure you are setup where it needs to be. The VVT for Intake needs work as well. Timing seems a bit low for 9 psi of boost. I am sure it is down on power do to these small things that need to be corrected. Hopefully this was of help for you?

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Hi guys thanks for the info. I will do the plugs and compression test first to see how it goes. I have a new air filter and have cleaned the intake etc when i was fixing some small boost leaks around te plenum. The vvti solenoids have been replaced as well as the exhaust cam sensor so these are fine now. Also i change oil every 5000kms so the engine internally should be clean, always comes out a tad off golden. Engine has done 150000kms, turboed at 120000kms. Thanks for the input for the vvti settings and i see what you mean about the vvti table and kpa etc. Dont want to change any settings just yet as it was running fine on this before. So trying to get back to how it was etc.

Brendon

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Did a compression test once it had warmed up, 

ResulResults were good so was hapoy with that! 

Cyl 1- 180psi

Cyl 2- 180psi

Cyl 3 -185psi

Cyl 4 -182 psi

The old plugs had been in for around 3 years thinking about it, done 30000kms on them (5 track days!)and had brown rings above the threaded part on the porcelain almost like compression lekage etc, fitted new plugs so will see how that goes :) dunno why i overlooked those...

Brendon 

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It starts alot better and idles more stable, drives perfect off boost but still tge same on boost. Almost feels like its missing the low down torque pull feeling it used to have. Will let my tuner know your feedback rich so thanks for that :) im leaning towards tubo just starting to wear out and loosing its puff. Was secind hand rebuilt when i got it 3 years ago so no idea of history or kms etc)

The picture attached is fron the dyno day, the previous runs were my initial tune 3 years ago on 7psi spring with no boost solenoid, the last green line is current with boost solenoid to achieve the 9psi. See how much lower down it is initially, thats the loss of power feeling im meaning.

Brendon 

20161203_090112.jpg

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The boost solenoid being open may cause it to have a little lag and start to already flutter the valve a little. But yeah it could very well be the turbo as well. Does not look as smooth between 2400 to 3200. Keep us updated. Always great to know the outcome.

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Hi guys, does anyone have a log file from an altezza 3sgebeams running the dual vvti, maybe a dyno session or road run so incan have a look at your vvti cam requestes position vs actual positions? Still trying to get to the bottom of this. Also have some movement sideways on my wastegate actuator flapper so may be a leak ther(not sealing properly), but would like to check some others logs to see what others same spec motors are doing etc before pulling off the dump pipe to have a look at the rear housing. Waiting on my tuner to send my original dyno log as well.

Thanks

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I would first lean towards getting the boost loss sorted. I am almost positive at this point it is the main culprit. If not then we can move forward. I will get a log file for you shortly.

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Hi rich, yes a few others believe it is all related, ie if my exhaust cam is not returning to the locked position or 0 at low down in the revs and kpa, then the exhaust cam is permanently retarded down low even though it should be off which affects my low down power and hence boost down low as well. Im also getting a bigger turbo, exhaust and manifold  with external gate in a few months so trying to rule out a few more things before then.  At that point the shop working on my car will check over the internals of the current turbo and do more leak down tests etc. 

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Brendon001

Here is a screen grab of a log from my 3sge Beams in my 86 corolla showing vvt tracking in the middle graph

 

vvt tracking.png

hey awesome thanks brad, so your when your exhaust target is 0, your actual position of the eexhaust cam reaches 0? I see its currently very close at around 0.8 etc and follows very close all the way and returns back to 0. My exhaust vvti cam actual position  never gets lower than -4.8 ie it never gets back to 0. Do you happen to know your exhaust vvti solenoid duty cycle value when  the requested position is 0? Mine shows as 20% when requested position is 0. Still waiting for my original log but getting the feeling my  exhaust cam is somehow not returning to the 0 position. 

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It sounds like the cam offset for the vvt is not correct. Running the CAM test fuction to confirm the correct offset is entered would be the first step.

How to do this is covered in the PC link help file. (Just search CAM test)

 

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Hi simon

I have done the cam test as per your suggestion. 

On the exhaust cam test it comes back with a steady value of 51.1 degrees atdc. On my DI2 exhaust vvti setup the value in the box is currently 48degrees atdc. 

Inlet cam test measures steady value of 45.4 degrees atdc and under trigger  2 vvt value it it currently 44.5degrews atdc.

 

So is the exhaust cam value slightly out? Would you recomend to change the exhaust value from 48 to 51.1? Would this make it track better etc.

Thanks 

Brendon 

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