(BPU TT AUTO) Boost Problem Misfire - Resolved

[Tayfun.tugra]

Hey guys, hows it going?

 

I have a boost problem and would like to get it sorted.

Car: 1995 TT Auto BPU J spec. RZ-S

Symptoms are:

Loss of power.

At 4000 - 4500 RPM misfire as boost drops when 2nd turbo should be effective.

Boost gauge shows 0.7 bar (should be 1.2 bar as BPU) and drops boost to 0.1/0.3 bar as stated in Ian C's informative post:

 

http://www.mkivsupra.net/vbb/showthread.php?35926-The-sequential-system&highlight=sequential+system

Problem 2: I don't get a 2nd turbo rush, and as soon as I should it dumps all boost instead.

The IACV is opening but the second turbo isn't spinning. All the air boosted by #1 turbo now has an easy path back to the non-pressurised side of the turbos via a non-spinning #2 turbo. In effect, it all goes 'backwards' through #2 instead of going into the engine. You'll maybe see .2 or .3 of a bar of boost but that's about it.

 

This usually means the EGCV isn't opening. The turbo can't spin as it has no exhaust gas flow path. Although annoying, this won't do long-term damage as #1 turbo won't generate much boost because the engine loses a lot of power, so no overspeeding or overheating.

 

I've put it in TTC and the problem still exists.

Checked all hoses and pipes. In good Condition.

 

So a few questions:

1. Does this still lead to the EGCV? As the IACV's are not the problem as they do not change the symptoms when in TTC.

2. What part of the EGCV? - EGCV VSV or EGCV Actuator?

3. Where is the location of the EGCV VSV?

4. Anyway to test EGCV VSV or EGCV Actuator to see which one is at fault?

5. Removal Guide if possible.

 

 

 

I've attached a picture of what I believe EGCV Actuator is.. and an arrow of what I think is a possibility of the EGCV VSV.

 

Does anybody have pictures they can kindly post up...

 

It seems a lot of members have this sort of problem. Im hoping to resolve this and contribute to a fix it guide if possible.

 

Thank you.

 

 

 

Note: Picture is as TTC mode as a test.

Will correctly attach image to prevent loss from external website.

 

Edit. Attached Image

Edited December 17, 2013 by Tayfun.tugra (see edit history)

[Tayfun.tugra]

And to add a little encouragement...

Those who help with useful information will receive 1* Feedback ( if possible) and a spot in my signature after fix

[Swampy442]

The picture is of the EGBV and the correct VSV, the hose in the picture should go to a pressure source, opening the EGBV. What guide did you use for the TTC mode? Ive used this with success :- http://mkiv.supras.org.nz/articles/andy.htm

 

By putting it in TTC mode you've eliminated the sequential control so either you've done the TTC thing wrong, or the EGBV isn't opening fully (you can exercise it by hand to see if it opens) Or you have another underlying mechanical issue.

[Tayfun.tugra]

The picture is of the EGBV and the correct VSV, the hose in the picture should go to a pressure source, opening the EGBV. What guide did you use for the TTC mode? Ive used this with success :- http://mkiv.supras.org.nz/articles/andy.htm

 

By putting it in TTC mode you've eliminated the sequential control so either you've done the TTC thing wrong, or the EGBV isn't opening fully (you can exercise it by hand to see if it opens) Or you have another underlying mechanical issue.

 

Hi swampy,

Thanks for the reply.

 

How easy would it be to exercise resistance wise? Is it push in or pull out?

 

I believe I have set up the TTC correctly.

 

However, encase I have missed something, here are some pictures.

 

.

.

 

 

Edit: Attached Images

Edited December 3, 2013 by Tayfun.tugra (see edit history)

[mellonman]

Hi swampy,

Thanks for the reply.

 

How easy would it be to exercise resistance wise? Is it push in or pull out?

 

I believe I have set up the TTC correctly.

 

However, encase I have missed something, here are some pictures.

 

http://i1143.photobucket.com/albums/n622/buffalo7/Mobile%20Uploads/Supra/TTC1_zps191237f3.jpg

.

.

http://i1143.photobucket.com/albums/n622/buffalo7/Mobile%20Uploads/Supra/TTC2_zpsb9ee28a9.jpg

 

 

Edit: Attached Images

 

 

 

This first picture of the iacv is completly wrong and why you are not getting your second turbo, instead of the loop on the vsv one goes to the acuator and the other goes to black boost pipe, for TTC i cant remeber if its correct or not

 

http://www.mkiv.co.uk/vbb/showthread.php?35926-The-sequential-system

everything you need to find the issue is in this thread

 

http://www.mkiv.co.uk/vbb/showthread.php?295192-RESOLVED-My-stock-TT-max-boost-is-0-6-(now-BPU-amp-0-79BAR)/page2

 

now you are already on this thread so please look at the picture of how the iacv should be plumbed

 

also the missfire will probably be coil pack clips if not that oil by or on plugs

Edited December 3, 2013 by mellonman (see edit history)

[Swampy442]

This first picture of the iacv is completly wrong and why you are not getting your second turbo, instead of the loop on the vsv one goes to the acuator and the other goes to black boost pipe, for TTC i cant remeber if its correct or not

 

For TTC the first picture is correct, actuator fed with a constant pressure source.

 

You should push it open, as in force the arm towards the back of the car.

[Swampy442]

This first picture of the iacv is completly wrong and why you are not getting your second turbo, instead of the loop on the vsv one goes to the acuator and the other goes to black boost pipe, for TTC i cant remeber if its correct or not

 

For TTC the first picture is correct, actuator fed with a constant pressure source.

 

You should push it open, as in force the arm towards the back of the car.

[BOB B]

I don't know much about TTC mode but I had the same problems as you have just described, does yours sound noisy and then blow when the second is supposed to come on?

 

On your first picture, yes that is the EGCV actuator but the arm of that connects to the actual EGCV which is between the the turbo's and your exhaust pipe, in the end I managed to get a second hand valve and changed them over (a pain in the arse job) but it did solve the problem, this was 3 or 4 years ago.

[listy]

Just putting it out there T, I had the same drama a while back. Checked all hoses and they seemed fine. I never found the problem though. In the end, I changed all the hoses due to a colour scheme change, and the problem went away.

I couldn't tell you which hose was at fault though

Might not t be any help, but that's my experience.

[supra_ufo]

it will require a lot of patience !

[Tayfun.tugra]

Thanks for the reply guys.

 

Theres small amounts of oil getting onto the rubber seal of the coil pack near the spark plugs on every plug. I've cleaned them off a few weeks ago, but its returned again... any suggestions/theories as to why this is happening?

 

I'll also check all the hoses again intensely, but they have been replaced already for blue...

 

I have a day off tomorrow, I'll stick it in the garage and take lots of photos for memory.

[Tayfun.tugra]

For TTC the first picture is correct, actuator fed with a constant pressure source.

 

You should push it open, as in force the arm towards the back of the car.

 

 

 

I don't know much about TTC mode but I had the same problems as you have just described, does yours sound noisy and then blow when the second is supposed to come on?

 

On your first picture, yes that is the EGCV actuator but the arm of that connects to the actual EGCV which is between the the turbo's and your exhaust pipe, in the end I managed to get a second hand valve and changed them over (a pain in the arse job) but it did solve the problem, this was 3 or 4 years ago.

 

It doesn't make any excess noise, but it does choke like an old man when the 2d turbo is supposed to come on.

With some assistance, Lee P also points to this direction as his suspicions is that the exhaust vsv (EGCV Actuator) may be jammed.

 

Yep I've tried pushing it in, space was limited but the thing wouldnt move, I got the pliers to assist my frozen hands with still no joy. I think this may be my problem.

 

 

Bob B - Is there a quick guide you can set me up with please?

 

 

Edited December 4, 2013 by Tayfun.tugra (see edit history)

[mellonman]

that picture shows that the egbv is fully open , if you are still in TTC that is why , have you pulled off the vac pipe to the actuator to see if it closes then ? , i have a spare EGBV if needed

[Tayfun.tugra]

that picture shows that the egbv is fully open , if you are still in TTC that is why , have you pulled off the vac pipe to the actuator to see if it closes then ? , i have a spare EGBV if needed

 

I'll try that now, thanks.

[Tayfun.tugra]

that picture shows that the egbv is fully open , if you are still in TTC that is why , have you pulled off the vac pipe to the actuator to see if it closes then ? , i have a spare EGBV if needed

 

I'll try that now, thanks.

 

Well, I've taken it out of TTC, and its Closed itself. When I push it open, it somewhat easily opens, no need for pliers.

 

So I'm assuming that working fine, would that render the sequential system working correctly with another problem at hand?

 

 

Edit:

Problem 3: The second turbo comes in late.

It seems like, instead of 4000rpm, your second turbo cuts in at 5000rpm or later. Usually this is caused by no prespool taking place - your IACV opens, your EGCV opens, but the second turbo is sat on it's ass doing nothing. So, not only has it got to suddenly get up to speed, but it's fighting against #1's output trying to go backwards through it. Hence, the looong lag.

 

This is usually caused by the EGBV not opening. You may notice more than 0.8bar of boost being generated by #1 turbo because of this, as the EGBV also acts as #1's wastegate.

 

21-9-2005 Update - this may also be an issue with the pressure tank. Investigations by Heckler and Soop Dogg are ongoing

28-6-2006 Update - Soop Dogg has found that a dodgy fotwell connection can cause it. Don't ask which one yet though. See FAQ on refurbing electrical connectors

 

Time to check this out.

http://www.mkivsupra.net/vbb/attachment.php?attachmentid=13950&d=1112559186

Edited December 4, 2013 by Tayfun.tugra (see edit history)

[mellonman]

The fact that it was still open after some time when still in TTC means you have no leaks, but would indicate that a vsv is shot

You said earlier that when your in TTC the car was not louder? Which is odd as the car should be alot louder driving around low boost (as both exhaust ports are open), maybe the egbv arm is no longer opening the valve, its a new one but could happen I guess if it not getting louder that is

Edited December 4, 2013 by mellonman (see edit history)

[Tayfun.tugra]

The fact that it was still open after some time when still in TTC means you have no leaks, but would indicate that a vsv is shot

You said earlier that when your in TTC the car was not louder? Which is odd as the car should be alot louder driving around low boost (as both exhaust ports are open), maybe the egbv arm is no longer opening the valve, its a new one but could happen I guess if it not getting louder that is

 

I have a slight hearing problem (too many subwoofers and amplifiers when I passed my driving test)... so it may well be louder, but its hard for me to tell with all the noise a decatted TT supra makes already lol

[mellonman]

can i just surgest that you get some in the car with out a hearing problem to help you diagnose the issue , pump the car as stock with all vac lines (dont pumb in any boost controler) drive the car no fast as slowly normal driving and make note of how loud it is then put into TTC and do a full boost run to get the system preasurised and then drive normal again making note of how loud it is ,

 

you problem seems like the egbv is not opening but it is ,which is why i would do this simple test to help prove its open

[Tayfun.tugra]

can i just surgest that you get some in the car with out a hearing problem to help you diagnose the issue , pump the car as stock with all vac lines (dont pumb in any boost controler) drive the car no fast as slowly normal driving and make note of how loud it is then put into TTC and do a full boost run to get the system preasurised and then drive normal again making note of how loud it is ,

 

you problem seems like the egbv is not opening but it is ,which is why i would do this simple test to help prove its open

 

Confirmed by my neighbour. .. its louder in ttc when cold and warm. Along with a few more Vibrations

[mellonman]

must be a vsv then mate,there is a way to test then in the repair manual on the home page

[Tayfun.tugra]

must be a vsv then mate,there is a way to test then in the repair manual on the home page

 

Will do ssome more checking when I get home

Cheers

[Tayfun.tugra]

Update:

*Not in TTC old pictures used*

 

I had it in the garage yesterday scratching my head as to what the problem could be so I decided to refurbish the coil pack clips (for the 2nd time in 3 months) and check the resistance of the coil packs. and do a compression test.

Turns out all 6 coil packs have a resistance of 0.9 -1.0 Ohms when cold

and compression was consistent across all 6 of 185 - 190 PSI (12.7 - 13.1 bar)

 

 

So the test drive was this morning and the car no longer has a misfire and second turbo is now becoming effective, easily reaching the legal speed limit *Thanks Mellonman*

For good measure, I then changed the spark plugs and will test again, take a picture of plugs and see what's going on inside...

BUT theres still the boost problem..

on the Sequential system guide:

 

What it should be like:

 

You get 0.7bar of boost on turbo 1, a slight dip in power between 3500 and 4000rpm, and then 0.8bar of boost with both turbos online. This should be a smooth and linear power delivery.

 

When modified with a boost controller/decat, you'll see an increase in boost after 4000rpm when the second turbo comes online. You may also get 0.8bar of boost on the first turbo with a decat. You'll feel the same power dip at 3500rpm but then a noticeable surge in power at 4000rpm when the second turbo comes online and hits over 1 bar of boost. Full boost is acheived before 4500rpm.

 

I've got the full decat BPU, but when the throttle is down progressively the boost is SOMETIMES raised no more than 0.3 - 0.4 bar of boost maximum at 5k revs, and sometimes 0.7 bar with both turbos online. 2nd turbo is effective at 4k revs.

 

I've also used an actuator pressure gauge to diagnose both the turbo actuators and are working : (Picture below are pictures used while in TTC, I am no longer in TTC)

.

.

 

 

 

Coil Pack Clips - http://www.mkivsupra.net/vbb/showthread.php?61141-How-To-Refurbish-coil-pack-connectors&highlight=pack

Resistance Values - http://www.mkivsupra.net/vbb/content.php?68-EFI-Ignition-(2JZ-GTE)

Sequential System - http://www.mkivsupra.net/vbb/showthread.php?35926-The-sequential-system

Edited December 15, 2013 by Tayfun.tugra (see edit history)

[Tayfun.tugra]

Today I'm a happy guy

 

In addition to getting rid of the misfire by refurbing the coil pack clips the other day, progress has further found the IACV VSV works, but not as 100%

as in this thread - post number 30:

http://www.mkivsupra.net/vbb/showthread.php?295192-RESOLVED-My-stock-TT-max-boost-is-0-6-(now-BPU-amp-0-79BAR)

 

It certainly seems that as the Supra matures, the IACV VSV should be one of the top on the checklist regarding boost issues.

 

All I need to do now is drive my rover diesel and hide my Supra keys for safety

 

Thanks for the help

[Tayfun.tugra]

I'll Reserve this space to do a checklist of diagnosis etc...

 

Will be posted later on tonight/tomorrow

[supra_ufo]

Thanks for the mention in your sig mate.

Goes to show its very important that people update there "problem" threads with a solution once they find one.