bluep

As above only got car on road and when i accelerate hard it seems to stall/stutter in any gear.Tried accelerating slowly and building up speed but it still affects it although not all the time.Anyone any ideas,any help appreciated

car has hks system,decat,and an induction kit.

Brun

What MY?

bluep

Its a 97 sti version 3 mate

greasemonkey

Not given us anywhere near enough to go on there, so this post is going to be more questions than answers.

Does the car idle properly, and does it respond as it should when you "blip" the throttle with the car at a standstill???

Did this problem appear all of a sudden or was it a gradual onset?

Is the car cutting out on-boost, off-boost or both?

Was the onset of the problem related to the introduction of the exhaust components or induction kit?

bluep

it was doing it before decat,filter was fitted system came with car

wanted

bluep, you haven't answered all the questions.

Take a few minutes to read and answer all the questions and I'm sure you will get some good advice from greasemonkey. Like he said not enough info

bluep

Sorry lads.The car idles perfect.When you rev it it returns to the same revs just under 9000 revs.As you accelerate slowly through the gears you can build the speed up,however if you try to boost from a low speed then you can feel the car hesitating at the top of the revs.I noticed this when i first got the car but i have been taking it easy because car was damaged and bought from japan so i have been taking it real slow until now.I did notice this problem though before i got the decat on .Also it seems to splutter and bang when slowing down, sometimes really loud but i assume this is to do with the exhaust system.Hope i have explained better as i would appreciate some help

greasemonkey

Are there any other mods fitted to it - an aftermarket dumpvalve perchance?

Also, what fuel are you running the car on?

What make is the induction kit, and do you have access to a standard induction tract?

Do you have a KnockLink fitted?

Brun

You still fitted the zorst when the car already hady a problem?

greasemonkey

Doesn't seem like the most sensible course of action, does it?

bluep

Do not have k.link.Runs on 97 oct super unleaded shell(strongest we have) and a forge dump valve.Filter is also hks. Might it just need spark plugs replaced?

greasemonkey

Would be worth getting and fitting one as a matter of some urgency.

That's not enough. Your car is mapped for 100 octane fuel. If 97 is all you can get (where are you anyway?) you need to get hold of some octane booster to bring the fuel up nearer the level the car is designed for.

Why didn't you mention this first off? Is it a recirculating or atmospheric venting valve?

Again, do you have access to a standard induction tract and air filter to fit?

As it stands knackered spark plugs don't sound the likeliest cause of your problem. Unfortunately there are so many non-standard trinkets on it that it's hard to say to what extent these might be contributing.

bluep

I live in N.Ireland.I was told the car would be fine on super unleaded by local tuner but i have went out and bought a box of millers octane booster.Dump valve is atmospheric although it still mis behaved with everything standard e.g filter,valve and exhaust.

greasemonkey

The advice you received from the tuner was unsafe. The only way you know the car would be fine on Super Unleaded alone is if you run a KnockLink, and it tells you you're safe.

As for the bits, the car was mucking about before you fitted them, but you went ahead and did it anyway? Not the best move by any stretch of the imagination as it makes it much harder to work out what's going on - things like the popping and banging on the overrun could be caused by the dumpvalve, or they could be caused by whatever is wrong with the car.

TonyFlow

my mate had similar on his UK MY99 - run DD on it, and found the lambda to be shagged (not likely to be your problem) - and the maf to be underreading (he has an HKS filter) Purchased new items and fitted - and all was fine!

Deltadash was showing the timing being pulled by 3 degrees before (which I asume was the stutter), after fitting the new parts, no timing is being pulled. Should also add, the MAF was covered in a film of oil and dusty sh!te!