On a MY99 Impreza (UK), what is the canister type item situated between the end of the radiator and air filter inlet below the front landing panel?

The reason I ask is because in the last few weeks I have been altering the map on my Link equipped UK car to eradicate overboost at peak torque and recently I have found that I haven’t been able to get more than 17psi from the turbo irrespective of adjustments made i.e. boost targets, WG rpm, base, sens etc.

I know it’s not recommended to run much higher than this on a std turbo’d UK car, but in the previous weeks I had difficulty in maintaining boost targets without overboost in either the higher or lower gears, hence the reason for making adjustments to my map, but now I can achieve 17psi peak, 16-15psi held with no problem. If I make adjustments, I see very little change, whereas before, slight changes made a big difference to how the car responded.

I did notice recently though, that I have been experiencing a whining, ghost like noise when accelerating under light load. At first I thought the standard dump valve may have been leaking, so changed the valve to an atmos one I had kicking around the garage, but this made no difference. I then thought that maybe the wastegate was passing and when I went to check, found a pipe had came adrift from the air inlet just after the air flow meter. This pipe on the canister is the left hand pipe which goes to what looks like a one way valve which branches off to the air inlet and another “T” piece which branches off to the inlet manifold at one end and the “pressure sources switching solenoid valve” (whatever that does!!)

‘Cause the car is having other things done to it at the moment, I’m not able to try it out, so don’t know if this has cured the ghost like noise but can anybody tell me what the canister is ?

And what is a “pressure sources switching solenoid valve” ?

If the noise is still there, is there anything else I can check to see what the problem is ?

Cheers

A

 

Hi Alan

The canister is an oil vapour catch tank. It has a drain out of the bottom and sends crankcase oil vapour back into the intake to be reburnt.

Have you checked that the noise isn't your power steering? If it is overheating (mine used to on hot days, using high revs) the drain the fluid by letting the return pipe fill into a carrier bag and then refill with Castrol ATX Dextron III.

The boost problem may be due to ambient temperature or a leaking part of the pressurised intake. Check all hose connections. The UK car could use some intercooler water spray on hot days.

I would talk to Uncle Bob if this doesn't cure it.

 

Hi all, its the fuel evap cannister.

Alan I've mailed you some tech info on the evap system of the car which should help make it clear.

Mail me the map if you like, sounds as though you have a leak somewhere though.

 

Indeed..

It is the carbon can.. to remove fuel vapour...

The purge solenoid connects into it.... it has "drain" underneath it.. that runs down the side of the engine bay and splits into two ..where it runs underneath the car half way...

J.

 

... runs halfway along the car and are terminated inside the little plastic breather thingys on the insides of the main chassis members. These breather outlets can easily be mistaken for something important.

 

Hi all

Pete:
Don’t think it’s steering related. Fault arises when car is cold or warm. May be leak in pressurised part of system but have checked security of pipes and can see no problem.

Bob:
Have mailed you the map I’m using just now…… Evap system was useful, thanks for that.

Cheers

P.S. Will update if anything found.