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Profec B Spec Ii Problems

Doobs

By Doobs,
in Engines & Forced Induction

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Doobs Proficient

Doobs

Posted
Posted

Hey People,

My profec is playing up. Just keeps boosting no matter what the setting.

Even when i switch it off it keeps boosting until i switch the ignition off then back on.

I've checked all vac lines and wiring, all look fine.

It started happening after i hadn't used the skyline in a few months and battery went completely dead.

Anyone had this issue before??

Thanks in advance.

Simon

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Krishy Grand Master

Krishy

Posted
Posted

when you switch the profec b spec II in "off" mode it will run the boost the actuator can handle.....so in most cases the actuator is set to 7psi or so....then thats what it will hold/boost up to

DVS JEZ Grand Master

DVS JEZ

Posted
Posted

what do you mean it keeps boosting, you mean its overboosting past 7psi or what ever you actuator is set at?

have you tried connecting the boost line to the actuator from the cooler pipe or where ever you have it sourced from, this should run stock boost, and you will know if the boost controller is playing up or if its the actuator

Checkbuzz Rising Star

Checkbuzz

Posted
Posted

At a guess I would say if it "keeps boosting" that it maybe that the "feedback loop" has been broken...

i.e. if the vacuum hose from the manifold to the EBC is pinched or split and is losing or blocking pressure on it's way back to the EBC it will try to compensate by cranking up the boost until it see's the expected pressure from the manifold. That is pretty much how EBCs work in a nutshell so I would be checking or just replacing that vacuum hose ($10) before spending big $$ on a replacement EBC or ECU.geek.gif

Good luck mate, I hope it is that simple & cheap for you!

  • 2 weeks later...
Duncan Grand Master

Duncan

Posted
Posted

profec B has power to the solenoid all the time, and pulses the earth to control the solenoid.

so....if the wire from the controller is damaged and is earthed, it will not short out, it will just run max boost all the time.

check for continutiy between chasis earth and the earth wire to the solenoid.

Rolls Grand Master

Rolls

Posted
Posted

sounds like the solenoid is jammed open, can you confirm it moves by opening it up? Possibly cracked vacuum hose? Wire earthed out and jamming the solenoid open? Try manually wiring the solenoid to 12v so it is always closed and see what happens.

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