I havent really run the scooby on the motorway as I've got a daily driver for that.. I took it up to Trax today and on the way there and back I noticed that if I little more than feather the throttle in 5th at 70+ the fuel cut keeps cutting in.. Its a MY97.. Problem is the turbo doesnt sound like its hardly working when the fuel cut kicks in.. Also If I drive the car hard its fine, I had a little run up the sprint strip at Trax which was smooth as silk and got a 5.03 which im pretty happy with, My launch was awesome but my gear changes leave alot to be desired as I kept looking at the speedo and not concentrating im sure if I had gone up a few times I could have seen 4's

 

bttt..

 

clean all your boost solenoid hoses...very common to cause this cut...happened to 2 of my cars..

 

I've replaced all the hoses with new pipe when i had the engine out to do the clutch, and the pipe with the restrictor in is brand new too

 

You could always fit a dawes or other boost controller & set it up just below fuel cut in 5th

 

when you say fuel cut what sort of thing do you mean? do you mean the car sort of kicks forward and back as you put your foot down and off again. or lack of power as you accelerate from 70?
just wanted to get a better understanding of whats happening.

 

It just feels like its hit a brick wall.. engine just looses everything for a second or two..

I've got a HKS EVC on the way which im going to try out.

 

ahh right so its like when a restrictor kicks in or something. but take it its not restricted.

i had that problem when i put new (wrong) spark plugs in but it happened all the time at 5000rpm. i gave my japanese labelled plugs to ngk and they gave me they thought would work but didnt.

does it happen in any other gear at the same revs? try 4th gear at same revs and see if it happens. it may be boost pressure if somebody has mucked around with it before.

 

only happens up in top when you've been cruising for a bit slighly on boost.. If I do a standing start and give the car some hard work its brilliant! no problems what so ever.

 

are there any mods to the car? either by you or somebody else has done before? has it always done this or you never noticed before?

how long do you have to run at 70 before it will do it? just wondered if its getting hot for some reason and ecu is telling car not to boost at all.

 

I've experienced the "high boost" fuel cut on earlier classics and this feels exactly the same, its a complete loss of power for a significant period, not like a missfire or bad ignition.

 

ok there is another thread on here about fuel cut on a my06 and it happened after adding a decat exhaust. if you have one then worth reading that. i know if the turbo solinied hoses are blocked or anything got in them then this can cause strange boosting.

 

New hoses.. and ive still got a middle cat..

 

it could be more along the line of fuel rad or injectors then. but strange how it doesnt happen in every gear.
somebody on here was saying that each gear is mapped individually so not sure how much difference that makes.
have you tried checking for error codes from the ECU?

 

I think you are plucking ideas out of the sky I think its a simple case of boost spikes but I'd be interested to work out why its doing it at such a bizzare point, when I can give the car a real hard time from a standing start and it behave so well.

 

You get slightly more boost up the gears,thats why if you fit a dawes you set it to just below fuel cut in 5th. Definitely just sounds like fuel cut to me, mine sometimes still does it on a really cold day flat out in 5th.

 

it is fuel cut, but why?

A failing MAF will cause it, do you run an induction kit?

have you tried cleaning the boost and map pipework out just in case there is oil in them from the trackday?

 

I've just ordered a HKS EVC so hopefully that will clean it up... Is the factory boost control a bit naff on the Impreza's? I've always found the idea of having a restrictor in the hose a little 'cowboy'

 

Im running a high flow pannel filter, the boost solenoid has been cleaned and all the pipes are new .. It was doing it on the way to silverstone and the way back.

I think everyone else on the road must have thought I had terrible clutch control