sti_sambo

My 93 wrx has been parked up for a few years and about 2 years ago it stopped boosting when you rev the engine; it would go form negative on idle to 0 but not boost up. I noticed when I took it for a spin that it did boost up if you keep your foot down for 5 seconds or so but only to 7psi not to the 12 it normally would.

I cleaned the boost solenoid today thinking that was the culprit but it made no difference, I also changed throttle position sensor as the case was cracked. I checked the actuator with a syringe full of air and in seems to operate correctly. I also held the actuator open a little with mole grips and revved but still no boost. There was a little oil in the exhaust so I checked the intake/intercooler and virtually no oil there and no play in the turbo shaft.

I'm thinking something has gone within the turbo on the exhaust side which is causing friction and stopping it spooling up, and causing the oil in the exhaust. Does anybody have any other suggestions to check before I start pulling it all apart?

Thanks in advance

bmw730i

Never had a car that makes boost stationary and what you describe when negative to 0 is normal when not under load.

Is the solenoid working and not just running of waste gate pressure?

Im not a expert and just stuff I have picked up along the way

sti_sambo

It always used to boost when stationary until one day it coughed on idle and stopped.

How do I check if the boost solenoid is working? I put the electrics in test mode and it was clicking away...

sti_sambo

Surely all scoobs should boost when stationary, otherwise you wouldnt't hear the dump/recirc valve when you let off???

Scoobyskott

Check that the acturator is working it sounds like the same problem i had i took off the acturator and it had started to sieze so i replaced it and it worked

sti_sambo

Checked the actuator and it seems fine but I haven't got a decent test procedure for it.

Checked the turbo too and all seems fine there: no damage to wastegate or impellers, all spinning freely, no sign of oil leakage.

sti_sambo

It also isn't showing CEL so I'm assuming it won't have logged any fault codes, is that right?

Scoobyskott

Have you tried reseting ecu anyway i had and 93 import that went into limp mode and drive fine till boost then it was like it hit rev limiter and ran like crap i reset ecu and ran fine again found out the kph converter was onits way out and it put her into limp mode but it showed no faults try the reset and see if she boosts