Was it a cold, damp day?

The increased density of the cold moist air will produce more boost and will lead to over boost, I have had this a few times, as far as I know it is quite common.

1.45bar after that, I would suspect the ecu had a mare and shoved the car into 'limp home mode' ?

Paul

 

Cheers Poc.

Must find out about the weather. Although as far as I know nothing under 5 degrees celsius last week.

To come to think of it, I wonder why his ECU did not cut the fuel.

Kind regards,

Wrexy.

 

Is the gauge correct? And are all the hoses still in place?

 

Hi Andy!

He has a Blitz digital boost gauge.

Hoses could be a possibility. I can't check now cause he lives a couple of hours away. Would a blown hose or hose that has come off, cause it to first overboost and then not be able to boost? Or would it keep overboosting all the time. What about the safety fuel cut. Shouldn't that have kicked in?

Kind regards,

Wrexy.

 

You can check wastegate functionality by removing the electrical connector to the boost solenoid. This should give you around .7 bar boost, which is the strength of the spring.

If that's OK, then I'd try cleaning all the hoses and the boost solenoid (has he recently had service, or topped up oil?) - just connecting one of the pair of under dash connectors puts the car into 'mad-cow' mode and cycles all the electrics...handily this includes the solenoid, making cleaning it a cinch. Keep your hands out the way of the fans though

Richard

 

Cheers Richard,

I too have a feeling it's his solenoid with gunk. I spoke to him again and he said it only does it on and off. Originally I thought it did consistently.

Kind regards,

Wrexy.

 

I had a similar problem on my 1999 STi V. The engine is brand new ...dont ask why... but during running in I have noticed odd boost figures. One gauge reads 1.3 BAR+ carnt really tell because it goes off the gauge. So I connected another and got 18psi. Does this sound normal??

Cheers

 

1.0 Bar = 14.5psi, so 1.3Bar =18.8 psi. It's close. Maybe one gauge was slightly out. Being an STI it could very well overboost to 1.3Bar on a very cold day.

You say during running in. How are you getting 1.3Bar? On part throttle or full throttle?

Cheers,

Wrexy.

 

Thanks for the reply WREXY....

I was getting 1.3 Bar by flooring it in 4th at around 30mph (50kmph)then abcking off quick as max boost was reached. So as not to over rev the engine (under 4500).

I asked around today and it could be due to my down-pipe. It is a stainles custom made racing pipe 3 inch and wide throat. An expert told me that this was very likely the cause of my over boost. Anyway changed it when I got home from work back to the cat original. I will check it again tomorrow and let you know.

 

FOZ STiV5,

That'd be interesting to see m8.

Cheers,

Wrexy.

 

A friend of mine who owns a MY99 was on the motorway last week and his car overboosted to 1.45 bar. On seeing this on his boost gauge, he backed off the pedal. After this, the car would not boost over 0.45 bar. Normaly he sees 0.88 to 1.06bar but now sometimes it sticks on 0.45 to 0.55bar. Car is standard with aftermarket exhaust and air filter.

Any ideas what's caused this?

Cheers,

Wrexy.

[Edited by WREXY - 2/10/2002 11:08:24 PM]