HI SOOB

MY 99 UK car, Full decat, up pipe changed, but currently running a std back box as the Prodrive on is being sent.

Turbo was changed for a VF28 and a Dawes device fitted, running 0.8 bar.

Car went like a rocket, until last week when it started to have problems above 3000rpm.
Garage had a look and put it down to a faulty MAF.
Changed it and it was better, got rid of the roughness above 3000rpm but its still only on 1/2 to 3/4 power.

Boost gauge reads .9 bar but its really slow.

Tried removing the Dawes device and running std pipework , so Im using the boost cut solenoid and all I get is 0.5 bar.

If i loop the pipe between the actuator and the turbo, I still only get 0.5 bar.

If I pull the pipe right off the actuator, the boost rises no problem, went to 1.2 bar and i shut the throttle again, incase of doing damage, but the power didnrt seem that great then either.

I removed the actuator from the turbo and I find that compared to the actuator from a TD 04 , the VF 28 one is easy to pull.

Could this be the problem?? a weak actuator??

HELP...........PLEASE

Delboy2

Has the ECU been reset since replacing the MAF sensor as 0.5bar when the standard pipework is connected would suggest the ECU is 'limp home mode' or maybe it is seeing another fault.

Cheers

HI SOOB

I reset the ecu by using the plugs under the steering column, still no better.

How would the ecu restrict it to 0.5 bar??

Remember that if i connect the Dawes device, it can read 0.9 bar on the gauge, but its still really slow??

Cant get my head round this bloomin' car!!!

Delboy2

When the standard solenoid is connected as you stated above the ECU can make the Turbo only run actuator pressure by not 'bleeding' any air from the boost solenoid therefore you will only see 0.5bar boost.
Even though you are 'bypassing' the standard boost control by using the Dawes if the ECU has or still is defaulting to limp home mode due to faults the ECU will still be running a safe map as it has seen/or is seeing a fault so the boost will be normal but the performance will be impaired by running the default map.

Cheers

HI SOOB

So you dont think its the actuator then??

The reset I did might not have worked.

Where do I go from here??

Delboy2

Highly unlikely

Maybe the reset didn't work or another fault has been detected

Cheers

HI SOOB

So what your saying is that if I run with the boost controller it will only let the car create 0.5 bar .

If I conect the dawes device, it will create the boost, but since the ecu is in limp mode it will have poor performance. Will this mean that if I use the dawes at 0.9 bar and give it some stick at WOT it will be under fueling and I run the risk of blowing her up?

I also cant figure out how if i loop the pipe from the actuator to the compessor side of the turbo , it still only creates 0.5 bar of boost??

Sorry for so many questions

Delboy2

It will only run 0.5bar of boost as this is the 'crack' pressure of the actuator - meaning that when pressure is applied to the actuator nipple it overcomes the spring pre-load pushing the arm which opens the wastegate thus regulating the boost pressure by diverting the exhaust gases from the turbine wheel.
When the original boost control is used, the above will be achieved by the ECU keeping the boost solenoid closed thus no air will be bled so the pressure will be governed by the actuator preload pressure (0.5bar)
It would be wise to see if the ECU has been successfully reset or there is no other faults being seen before 'giving it any stick'

cheers

HI SOOB

So the ecu retards the timing to restrict the boost to 0.5 bar when I am using the factory boost solenoid??

Is that how it keeps 0.5 bar??

But the car can rev up to red under load

john banks

Get someone that knows what they are doing to look at it before you blow up the engine.

HI SOOB

Yeh, will do matey.
Was just asking