The turbo boost on my JDM STI is running at 0.7 bar, which is apparently 1/3rd below its normal capacity of around 1.2 bar. Can anyone shed any light as to what the problem could possibly be? I've been told it could be the turbocharger itself, which I don't really want to believe, not on a 12000 mile car! Could it be something electrical, sensor, solenoid? Any advice greatly appeciated, as always!

 

Fuel are you using mate? This happend to me, but was only about 0.2/3 bar, because I put BP ultimate in it, which made the advanced multiplier drop to around 3, which = no boost.

 

Tesco 99 or Shell V-Power

 

Hmm, Cant help you then, When i put shell v-power in afterwards, reset the ecu, and carried on, it was fine. Now boosts at 1.44 Bar

 

The ecu retards when it sees a problem, thats all its done, though note that if its retarding with the fuel you have in, its best to be adding something like millers octane plus

Tony

 

Thanks Tony!

I wouldn't think of something so straightforward! I've just picked it up from my local Subaru main dealer, who says they need to spend some time trying to diagnose the fault. Spoke to the technician there and he mentioned a couple of solenoids which could be faulty. He said it was very unlikely to be the turbo itself, although Powerstation were sure it was the turbo. The problem was initially discovered at Powerstation when I took the car for a remap and Miltek exhaust a couple of weeks ago.

I will go to Halfords in the morning and buy some octane booster as you suggest, and I'll let you know if there is any improvement!

 

GREGGYG halfords don't stock millers octane plus.What turbo boost does the standard Jdm sti run.I have 05reg Jdm sti running on V-power and millers octane boost .Don't have a boost gauge in the car yet .

 

I've been told by Powerstation it should be around 1.1-1.2 bar, mine is 0.7 bar. That's what I saw on the powerstation computer, and the same figure appeared on the Subaru computer at my local main dealer.

 

Could be faulty knock sensor. Apparently backs the boost off a little and retards the timimg. Had similar on my MY02, i only used to hit 0.9bar with ppp fitted. New knock sensor fitted made it boost better (although i now have fluctuating boost now so am posting a seperate thread after some searches)

Mark

 

Thanks Mark,
I'm booking the car back into Cheam motors Subaru main dealer next week, so hopefully they will find the problem. I'll mention the knocklink.

I just looked on the Halfords website and they have NOS octane boost street formula, which I presume is similar to the Millers stuff, so I'll try some of that tomorrow.

 

could this be in safe mode?

as when the ECU detects a fault it put it self into safe mode which will run a lower boost??

not sure on this but i am sure if its on a classic.

hope you get it sorted asap, my 03 STI JDM got mapped by Powerstation 355bhp/350lbft