Hi guys,

I did search about this problem.. and read a lot.
But I can't figure it out.

The car has stock seq. twins

Car boost 0.9 bar to 4500 rpm
then boost drops to ~0.3 bar

The Charge control valve is switching at 4500 rpm
Charge relief valve is ok.

So I gues the turbo control actuator is not working.
Is that correct thinking ?
How to test this ?

With no load will the valve switch ?

Thank you !

 

im tracking down the very same problem... and have searched the entire board for hints... Primary hits 13psi by 3800 rpm and holds until 4500 - i know that precontrol is getting pressure, but i'm not seeing any airflow from the 2ndary relief valve. At 4500, boost drops steadily to about 6psi, then at 5500 rpm, it rockets back up to 13 (I'm at 6000 ft - boost pressure will read a bit higher up here)

Check that youre pressure and vac tanks hold. Mine held for a few minutes, but after i replaced the check valves, they held pressure all day. if they leak at all, then there might be some pressure bleed off as the differential increases.

Do the KOKO test, then to test the switching solinoids, temporarily attach your boost gauge to the actuator side lines to watch for pressure.

I've already tested the precontrol and wastegate: my precontrol is getting pressure when expected - however, i didn't ever see the precontrol move per the koko test. (and I got the 4psi during the test)

Then check the pressure and vac line on the turbo control. thats my next step. I didn't see the turbo control even move at when specified during the koko test.

I've also seen some references to a badly adjusted tps will cause 2ndary boost to delay to 5500 rpm - that doesnt seem to be happening to me because of the boost drop at 4500. Its on my list though - easy to check.

If i find out what solves it, i'll post. Please do the same

-J

 

In the koko test, the turbo control and charge control valves should move. The wastegate and precontrol should not.

Davd

 

I have tested the Turbo control valve now with the KOKO test.
The valve is not moving.

The charge control valve is moving.

There is pressure at the presure tank and vacuum at the vacuum tank.

What is next to test ?

 

Now check the pressure hose to the Turbo control valve.
At 4500 rpm it is 7 psi.
It slowly drops to zero.

Now I want to test the vac hose to the turbo control valve but it is to hot

How much pressure chould there be at the pressure chamber ?

 

There should be 10+psi. Whatever boost pressure you reached before 4500rpm should be in the pressure tank.

I think either your check valve to the pressure chamber is leaking or the hoses themselves are leaking. You're on the trail.

The vacuum side should be around the amount of idle vacuum. The precise amount of vacuum will vary in the system depending on which solenoids have been active and the last time you reached maximum vacuum.

Dave

 

update

solenoid that switch the vacuum to the boost control valve was broken.
Replaced it but still not enough boost.
first is ok... when second come online boost drops to 0.4 bar.. then slowly climbs to 0.5 bar

The turbo control valve is switching I think ... with the KOKO test I see it move.

I don't know what to do next

 

update again

I was looking for a way to find out if the pre control acuator is moving.

used the hose that is on the pre control solenoid.
with a T piece from the charge relief provided the acuator with full vacuum. (till 3000rpm)

But now the engine can't hold the vacuum..

So I put a hose direct at the pre control acuator.... with a vacuum meter.
Suck it... but now vacuum.... So the acuator is leak I think.

 

First, look for leaks on the hose between the charge relief valve and y-pipe, and also the main couplers. A leak at the CRV will not affect boost below 4500.

I'm not sure what you're trying to do with the precontrol and t piece. The precontrol actuator sees whatever pressure is in the primary turbo compressor - so if the engine is idling you will see only vacuum. Under boost, I think the ECU will duty control the pressure in the actuator during the prespool phase (2500-4300rpm approximately).

How exactly did you verify the charge relief is working properly?

Dave

 

we tested the charge relief valve by putting pressure at one site.... with vacuum the valve is open.

I used the vacuum to te charge relief valve (system vacuum) to test the pre control solenoid.
tested the solenoid by just putting a hose with vacuum to it.

I was thinking a way to test the acuator..
It need vacuum to switch, when I put vacuum to it nothing happens.

Then I put a new hose direct to the acuator and just sucked on the hose...
I can suck what I want but I can not create vacuum. So I gues the acuator internals are leak

The acuator is connected with to hoses... one from the pre control solenoid providing it vacuum.
But what about the other hose.... that should be a sort of waste gate control

What is the best way to test the pre control acuator when the car is not running ?

 

Did you check the Charge Control ACTUATOR (the one sitting at the top/back of the Y Pipe?

How would you actually check to see that it is functioning (opening the flap) ?

 

I don't think the precontrol is your problem, I think the CRV is. If the CRV works, (which your testing indicates) the solenoid or the lines between them could have a problem.

I suggest you unplug the CRV from the airbox and let it vent directly to atmosphere. If it's working, you'll hear air whoosing below 4500 but it should stop before 4500. Then I would look at other things, possibly the precontrol.

The precontrol actuator has two nipples, to test it you must join the two with your tee fitting and apply pressure. It operates by pressure, not vacuum. You should see it move with 10-14psi. Don't apply more than that. (ref FSM F-89)

Dave

 

He mentioned he saw it move with the KOKO test.

Dave

 

the charge control acuator is moving with the KOKO test.
At 4500 rpm boost drops... So I gues the the air is flowing to the second turbo and not to the intercooler.
So the valve should be open to do that.
There is now noise of air escape outside.

When I work all list on the internet to check the turbos I am now at the pre control valve.... But how can I test if it is working.
I want to figure this out.

 

**** I just looked at the diagram again... And there should be pressure at the pre control acuator and not vacuum.

Will test this tomorrow.

 

wastegate actuator is working when putting pressure to it.
Pre control actuator is working when putting pressure to it.

checked the CRV again and it is ok.

When driving....pre control is getting 10 PSI. till 4500 RPM it is vibrating. (duty cycling ?) after 4500 RPM the same as the boost 7 PSI

The CRV get vacuum till 4500 RPM. After that it is zero and climbing with boost.

What is next ?
Is the second turbo broken ?
I can turn the turbo around.

 

It sounds like the tests you just did indicate everything is normal. The jittering of the precontrol is the duty cycling.

Your secondary turbo is probably not damaged.

Sorry for sounding repetitive, but I'm not sure that you've ruled out the CRV venting boost at 4500+, or a leak between the y-pipe and CRV.

When you did the KOKO test, how many times did the you KOKO before the CCA and TCA stopped cycling?

Dave

 

Th vacuum to the CRV is ok... before 4500 it is 0
But the strange thing is that I do not here air leaving it at all.
So I looks like there is no second turbo spooling.
When the car is standing still and I hit the trottle there is no air leaving the CRV
If the CRV is not working I should get more PSI at higher RPM... But after 4500 it is about 7 PSI till redline.

KOKO test more then 5 times no prob.

 

sorry from idle till 4500 te CRV is getting cavuum...after that it is zero and even pressure.

 

Did this ever get sorted out? I think a lot of people are having the same problem at the moment.

 

No not at all.

I have disconnected the charge control actuator and turbo control actuator.
Then I opened the valves en tied them down... now the second turbo has to work.
But at 5000 rpm I'm getting 0.5 bar 7PSI
and it slowly climbs till 8-9 PSI till red line

 

please someone help me

Did the poormans non seq.
all vacuum hoses are out now except the wastegate en purge control
Car is starting fine. Idle if good.

But still 0.5 bar (7psi) at 5000rpm and not getting more.

I tied the turbo control valve to the front of the car.
Did nothing with the pre control valve.. no hoses to the actuator.

Charge control valve has still got the actuator but no hoses connected.
actuator is out (not pulled in)

when the car was still seq. the first turbo was strong 10psi.
but when second opened 7psi.

what could I test more ?