Nahpets

Hello!

I have suffered from boost loss and have in my quest to find the answer pressurised downstream beginning from IC inlet at 0,8 bar. The system is tight enough and the small small leak found at the TPS cant be the answer to my 0,5 bar loss.

So I have now isolated the cycling valve to be a potential culprit.

So here is my question, but first a description:
- The cycling valve leads by default (zero voltage) air from C to W.
My cycling valve leads 95 % of the air, when blowing into gate C, to W which is the control signal to the wastegate.
- If I connect 12Volts to the CV (a loud click from the valve actuating is heard) and blow into C, 65 % of the air is leaded to the R outlet (back to the turbo intake) and 35 % to W !!

Is this a correct behaviour of a correct operating CV ?

Added to this I have an air leak around the terminals where the harness is connected. See arrow. This leak increases when CV is activated.

Please advice.

Cheers
Stephan

Nahpets

Truth is out there ...

dillon410021

what will usually happen is the lines going to it will break or the plastic nipple ends will break. Pretty much all the vacuum lines near the engine will break if they are not replaced.

Nahpets

I have checked all hoses and replaced suspicously bad ones and tied all vacuum lines or clamped depending on size.

There are no cracks visible and if I blow through it (pressurizing blocking outlets) there is no escaping air.

Cheers
Stephan

JohnKoaWood

Why not get an aftermarket boost controller, delete the ICV and be done with the issue from a stock part broken or not thing? Lindsey has them, as does SFR and even could go to Advance Auto or Napa and order up something... Even do the delete with a MBC if a full electronic boost control is out of price range...

Nahpets

I am an old bloke ... 31 years old and don´t want to disturb the stock look too much .

Cheers
Stephan

BGA9512

Stephan, have you considered that the car is in "limp mode" whereby the DME limits the amount of boost created to protect the engine? 0.5 bar loss of pressure would put you at about that pressure. There are various threads about causes, including the Throttle Position Sensor.

I had a few similar leaks around my cycling valve before I replaced it, but could still make close to full boost. Good luck.

Willard Bridgham 3

Have you checked the blow-off valve?

Failed BOV gives the symptoms you describe.

Nahpets

I have currently another chip with a leakage valve ( is it called so?) between the cycling valve and wastegate.
For some reasons I have difficulties to reach over 1 bar ... and this was before I changed the chip so I dont suspect the new chip.

The car is not in limp mode. My installed boost gauge tells me 1,5 bar absolut pressure when full throttle and no leakage in valve. So I am 0,25 bar behind stock pressure ...
What Ive done:
-I have changed BOV. The old one was by the way bad. This increased my boost somewhat, but still not all.
-I have pressurised my intake. No leaks of concern. Have changed the o-ring in the TPS. Was leaking somewhat, but not that much.
-Checked the cycling valve. Seem to function. Hoses to it is checked and its conections.
-Removed intake manifold to check hoses, venturi ****ty parts and reclamped with new ones.

Tomorrow I will reinstall my intake manifold and give it try again ...
I suspect wastegate more and more ...

Cheers
Stephan

Willard Bridgham 3

Have you checked your cat? Is it plugged? Same symptoms.

Have you checked the turbine exhaust pipe? Is it collapsed? Same symptoms.

Nahpets

How do I check the cat the easiest way?

By collapsed you mean there is a crack or hole on the outlet of the exhaust from the turbo device?

Cheers
Stephan

Willard Bridgham 3

Take the cat out and look through it....you will see if it's plugged. It may also have collapsed in which event, when you shake it, you will hear stuff banging around. If you have access to an air table, measure the pressure drop through the cat. Pressure drop should be in the range of 2.5 psig.

You will have to take the turbine downpipe off. It is 2 layers and the inner pipe is the one that collapses. You will see the collapsed portion.

hodmandod

Hi Nahpets
Before looking at exhaust pipes, which are a real pain, just clamp the rubber tube from the cycling valve to the wastegate, and drive the car very carefully, as the wastegate will remain shut. If it spools up normally, the turbo, pipes etc. are all fine, and the problem is the Cycling valve, OR the information it is receiving from its sensors, or the KLR brain is faulty. I have your problem, and you can fix it by putting on a Lindsey Boost Enhancer, which puts a 10 psi poppet valve from the intercooler intake pipe to the cycling valve. I do not know why this works, but it does. I guess it gets it over the 10 psi hump, as the valve does not open until a 10 psi buildup. However, I am concerned that I am stopping a sensor from doing its bit, such as the knock or TPI sensors. After all, the car is not boosting for a presumably significant reason.

Nahpets

Thanks for your inputs!

Next weekend I will the car out for a spin and clamp the cycling valve to double check there is boost.
I have removed the intake manifold and changed clamps and double checked the venturi hoses.
I will get back !
Cheers
Stephan