ClassicScoobyJay

Could anyone hazard a guess as to why, under anything but very gentle use of the throttle, my boost fluctuates back and forth from .6 to 1.2 bar? The car thrusts with it - so it's not just my gauge playing up.

It happens in every gear, and seems better if I very gently open the throttle until I get about 0.5 bar and then press harder from there.

Help!

MadGrip

it seems like a common problem mate, which happens to my 01 WRX aswell but only in 4th and 5th (occasionally 3rd).

I posted a thread asking for similar advice , but it seems theres no definate answer at the moment.

hopefully you'll find out what it is

Phil
www.wyioc.com

The_Judge

If you're using the stock boost control, my first move would be to connect green connectors together beneath steering column, turn ignition on (but not engine), then clean the wastegate solenoid and surrounding hoses with brake cleaner. Also check the T-piece and restrictor aren't clogged in the hose between the compressor and the wastegate actuator. And ensure your engine oil is halfway between min and max...

ClassicScoobyJay

MadGrip - Good to know I'm not alone (not good for you of course )

Judge - Thanks for the tips

I've tried the 'ECU in test mode then spray brake cleaner in to the wastegate solenoid and surrounding hoses' fix to no avail. I may try this again and be a bit less sparing with the brake cleaner.

Unfortuantely I don't really know my way around under the bonnet too well (I found the wastegate solenoid via a picture you posted Judge ), so I don't think I have much hope of finding, let alone checking that the T-piece and restrictor aren't clogged in the hose between the compressor and the wastegate actuator.

Unless some kind Classic owner could post a pic of what I need to look for?

p.s. I'm pretty sure you are on the right lines because my engine oil was topped up over maximum during my last dealer service.

The_Judge

Indeed. Get some oil drained out...!

ClassicScoobyJay

Judge you are a diamond - thanks mate.

I'll disconnect the pipes (as shown in your 3rd pic) and give them a good clean through.

I'll post back on this thread if this resolves the issue.

The_Judge

Fingers crossed...

ClassicScoobyJay

It worked!

I re-cleaned the wastegate solenoid and surrounding hoses & T-piece, restrictor and hoses between the compressor and the wastegate actuator with brake cleaner.

First of all I gave them a half-hearted squirt and took the car for a long test drive. The fluctuation had reduced, now moving between about .7 and 1.0.

That was proof enough for me that Judges advice was along the right lines so I got back under the bonnet - removed all the above mentioned hoses and gave them a thorough squirt, followed by a good blowing. (fnar fnar)

I then took the car for another test drive and the problem was fixed! Boost rose to 0.9 under WOT and stuck there.

Hopefully this thread will help others with similar symptoms. The moral of the story seems to be don't overfill your engine oil resevoir (or let your dealer do it during a service - worth checking up on them afterwards).

The_Judge

Splendid news! Have you also drained some engine oil out...?

ClassicScoobyJay

My service was 5 months ago so I've burnt off enough oil since then to be safe (I hope...). Dipstick now shows it's about 7/8 full.

If I experience any more troubles - at least I know the fix now

Thanks again mate.

The_Judge

Nice one.

ZIPPY

All the MY01 onwards cars i have seen and worked on have all suffered this boost condition.Brake cleaner didnt always work,i have found another cleaner that i personally use which does the trick every time.

It is definately down to the boost solenoid.Keep cleaning it several times if needed.
Now to the reason i have found on 3 seperate 01-02 cars as to why this happens:
If you gun the car in 1 st gear as in 4000rpm upwards, the car then pulses on boost afterwards in the higher gears in particular and also loses its normal 'eager feel'.I tested this several times and had to clean the boost solenoid afterwards to get it back to normal.
If you drive normally in 1st and then gun it in any other gear it stays perfect.

The mappers on here have all suggested using the 3 port solenoid to try to cure the problem.

Last point,this happened on all the cars when they where standard and even after they all were custom mapped (Ecutek)


Zippy