andyr_uk

Hi fellow scooby owners,

I finally got round to myself the Impreza Turbo I always wanted a few weeks ago, and am generally pretty happy with it. The only problem I am getting with it is a loss of power over the last week.

This problem seems to be intermittent, for example it was well down on power most of last week, but I took it on a long run down the M4 at a constant 80/90 mph and that seem to bring the power back again. And on my usual commute, and the power dropped off under hard acceleration in 4th gear, and I'm now back to square one with virtually no boost from the turbo.

The turbo itself sounds like it’s trying to do it’s job, winding up at the right place, and the dump valve hissing correctly when getting off the gas. Although I can verify exactly how much boost I’m getting as I don’t have a gauge.

I thought maybe it was blocked injectors, so I’m in the process of putting a bottle of injector cleaner through.

The car is a standard 1998 Scooby Impreza Turbo apart from a ScoobySport Exhaust and K&N Induction Kit.

Does this problem sound familiar ?

Thanks in advance for you advice.

RICH WILD

Hi,

first port of call for me would be to check all your hoses for leaks/spilts etc and check all jubilee clips for tightness. Pay special attention to the hoses round your intercooler. What dumpvalve is on there too? Sounds like the car COULD be leaking boost.

Failing that it's usually a process of elimination.

But do the cheap checks first

Oh, and get a boost gauge too

Cheers

Rich

nom

My guess...
Sounds like a possible 'normal' hot weather problem to me
Given the weather, det is much more likely. If there is enough det (not a lot needed!) the ECU 'panics' and maximum boost drops right down to actuator pressure, which is around half a bar (usually it's around 1 bar with the MY98, I think). Which means a noticeable drop in power! The ECU will then 'reset' itself over time if it doesn't detect more det, hence a return to power.

Ways to get round it? Use Optimax, or failing that, SUL. If the weather's really hot, it can be worthwhile chucking in some octane booster as well.

andyr_uk

Thanks for both of your replies.

Done a bit of reading about det and doesnt sound too good, but hopefully it's only a temporary thing while the weather was hot. How long does the ECU take to reset after it detects det ?

I have also read that a dirty boost solenoid can cause a leakage of boost. Is there any reason I should not attempt to clean it out ? I'm still hoping it's this, as this means no damage is being done.

nom

The intermittent nature would, to me, mean that it's likely to be the ECU (it's the most likely answer to the problem, anyway). It could be something else, but most hoses don't fix themselves, sadly
How long it takes to reset depends on something going on the ECU. Who knows what? I have found in the past that simply switching the ignition off then on again clears it, but it's a later model so is likely different.

nom

Oh - and I'd get a KnockLink too. Then you can see if it is knock & adjust your driving when needed, or if it does it a lot, look into it more!