yodajedimaster

As above, had a spirited drive into work this evening and when I was waiting for the engine to warm down I noticed a ticking under the negine. Popped the bonnet and located the noise to just behind the airbox on left hand side of engine bay. It sounds like a relay tripping constantly, very rapidly.

Thoughts?

What are the plugs etc that the small pipe goes into behind the airbox?

Robert.

jaytc2003

iTrader: (1)

boost solenoid?????

yodajedimaster

Would I get a fault code from the "Check engine" light with this? What exactly does it do?

Robert.

yodajedimaster

Just carried out a search for a boost solenoid picture, found one and I can definately say that this is where the rapid ticking is coming from.

What is the problem then, what effects will it have, is the car fine to drive home tomorrow after night shift?

Robert.

andy97

iTrader: (1)

They sometimes do this, nothing to be worried about, mine stopped clicking by switching off the ignition and then back on. Ive owned my Subaru for 9 years and its always done it after a spirited drive, just a glitch I believe

yodajedimaster

Thanks for this, panic over.

Whilst I've started the topic I wouldn't mind understanding what exactly is happening when the solenoid does this. I found a description of how the solenoid and wastegate work which is as follows:

"Both the WG solenoid and spring work together to close the WG and hence allow inital boost to build up. Once boost is around 0.6-0.8Bar a diaphragm actuater pushes against the WG spring and without a solneoid would quickly open to release all excess exhaust gases - hence limiting boost near this value. However your ECU kicks in beforehand and activiates the solenoid to keep the WG closed again (by gradually increasing WG duty cycle) and thus allowing boost to grow beyond 0.8Bar. In otherwords the diaphragm pushes/balances against the WG spring and solenoid."

So what exactly is happening with my car at idle, when it should be off boost? ECU fault?

Robert.

Scott.T

iTrader: (2)

The ticking will be present all the time the throttle is open as this ticking is the boost control solenoid trying to control the boost.
It shouldn't do it when the throttle is closed.

If the car is a pre96 then the throttle mechanism has an idle switch switch to turn it off when idling.
This can be demonstrated by cracking open the throttle by hand (under the bonnet). When you come off idle the clicking should start again.

It may be after a spirited drive that the rest postion of the throttle is slightly out of tolerance due to the heat, and hence the ECU thinks the throttle is open and hence keeps running the boost control solenoid.

If it is post 96 then I think the same priciple applies, although there is no throttle switch just a low voltage output. I'm not sure you can demonstrate this under the bonnet as I have a feeling there are other factors that cause the boost control solenoid to start running.

robsw

Robert, there is a bit of info on this thread:

http://bbs.scoobynet.co.uk/showthread.php?t=509193

Robin.