Crd boost problems

[UK-Rushy]

I'm having issues with my boost, coming up hill or sitting at highway speed, on slights acceleration, boost will sit at whatever the dawes is set at, usually 20psi, then as soon as I accelerate more the boost drops to around 10psi and fluctuates until it reaches 15/16 psi. Here's a link to a video http://youtu.be/EEQ12GpRx6A.

Details of car:
2008 crd manual
Cross country intercooler
Scotts rods 3" exhaust
Full egr block (exhaust mani side)
Chipit dom3
Dawes valve

Now before anyone hurts my chips feelings, here's what iv tried:

Replaced boost solenoid with brand new unit
Removed chip
Removed dawes valve
Replaced vacuum lines

The problem isn't as bad without the chip, but factory boost is a lot lower.

Iv posted this up on patrol4x4 and people are helping me on there aswell but it's always good to get as much help as possible!

Cheers!

[mudski]

Sounds like a boost leak maybe. Hard to tell. Have you got a needle valve installed too?

[threedogs]

have you looped off the air solenoid near the air filter.
I'd be re checking all hose connections and boost gauge conections

[UK-Rushy]

Iv replaced the vacuum lines and no need to loop off the solenoid as at the moment I'm still using factory boost control, it's definatly not a boost gauge problem as you can hear the spool.

also when I was using a needle valve before I had issues with the turbo staying on full boost when cruising and if I wound the spool down too much it would be laggy and under powered

Starting to wonder if it's a problem with the actuator or turbo it's self

[threedogs]

how many Ks on the motor and any other problems,
Might want to unblock the EGR and see how that goes if your on ECU boost

[mudski]

also when I was using a needle valve before I had issues with the turbo staying on full boost when cruising and if I wound the spool down too much it would be laggy and under powered


Your winding the needle valve off too much then I would think. To set the needle valve. Have it closed right off, start the car, and the actuator arm will go right up into the diaphragm. Slowly open the valve until the arm drops around 1/4 on an inch then take the car for a spin. The starting point you want is around 10psi at 100k's. This is all dependant on what your max boost is too. Say for around 16psi max boost. If you have higher and you set the mid range boost at 10 psi the car will be laggy so you will need to set it higher by closing the needle valve off slightly.
I run 19psi so I run around 15psi at 100k's. If I go lower I lose performance.

[UK-Rushy]

Motors just coming upto 120k, bought it at 108k and had dawes and needle up until lately when I went back to factory boost control. I did unblock the egr a while ago and still had the same issues, used to spike to 25-30psi, soon as this happened the dawes went on!

I threw the needle valve back on last night and stuck my hand on the arm and felt it drop, probably not 1/4 but I still need to wind it out abit anyway, the boost still seems to sit high on highway speeds but il wind it out a little before I drive home.

Cheers for the replies!

[mudski]

The arm should go up, not down. With the valve closed that is. Then drop down when you open the needle valve.

Just remember the needle valve does the "fine tuning" so it can take a bit to get the sweet spot. Be persistent and you will get there.

[boots]

Take away factory control and plumb it direct . Your ECU is reducing boost to increase EGR .