Andy/Gordon - Since adding full catless exhaust and HKS Induction kit (boosted power on the dyno by 40+ bhp!) I have had a bit of a problem.

I also had the Lambda sensor replaced and that stopped it happening so frequently/got it running virtually 'normal' again.

Still have the 'Overboost' problem from time to time though. Apparently, this can be solved by a re-map of some sort but I haven't taken this route just yet.

Also, mine is an import so no warranties/Subaru dealers for me!

Gussie cup

Funny you should say that, I've got a Grp A Mongoose stainless steel exhaust fitted recently and I'm in the middle of buying a HKS Induction kit. But I have to say, that "Problem" has only happened once and I don't think I had it before the ss exhaust went on. But that doesn't mean to say the problem wasn't there in the first place.

When I took on that cossie, it was the first time that I actually hammered the car - it's in too good a condition to get hammered on a regular basis.

Anymore ideas on what the problem can be?

Don't know if anyone would like to confirm/deny this theory below:

Added free-flowing (also Mongoose) exhaust/Induction kit - I would expect that air now moves through the system at an increased rate.

If the car (ECU) is still expecting the old levels of airflow in and out, will this cause the above problems i.e overboost, slight mis-fire under heavy acceleration?

Seems to make sense to me, but its more a guess than based on fact. Feel free to correct me..........

it seems strange but thanks for raising the questioun!! i own a 96 wrx sti..full scoobysport system.ive noticed recently going onto full boost mainly in 1st2nd i do get what i would describe as missfire..however,somebody has pointed out to me that it could be the larger opening on the down pipe actually blowing a plug out momentarally?? i am going to take advice from info suggested above regarding coil/packs and plugs though.. thanks

Folks

I need your help. I was keeping a modded 2wd cossie company last. Then when I decided to finish him off and floored it, my scooby started misfiring. I was in fourth gear, in the high mph's when it started spluttering. I then changed into 5th and it did it a few more times before the problem disappeared. It felt like as if it was (a) dirty injectors (b) fuel starvation or (c) something else. It must have spluttered about a dozen times before the problem disappeared. It was a bit like hitting the rev limiter but I was no-where near it.

Has this happened to anyone else? What could be problem? Can anyone please help me?

Gordon,

I had a similar problem just before Christmas whilst overtaking a few cars & an articyulated lorry. Scary I tell you....

It was diagnosed as the Coil Packs, they were cleaned as they were very dirty. They seem o.k. now but I'm gonna replace them when I get a chance.

Neil

Neil

Thanks for your help I'll definately look into it. How much did it cost you to get the coil packs cleaned? How old is your car? Mine's a R reg and I didn't think it was that old that the coil packs need to be cleaned?

We had a misfire problem with ours which turned out to be spark plug gap.

Gordon,

Mines a 95 WRX, the garage cleaned the coil packs for nothing as a favour. The Plug gap may also be another thing to look into, 0.7mm usually on the NGK platinum tipped type.

Neil

Neil/Mandi

Thanks for your replies, really appreciate them thanks. So what I thought about blocked injectors and fuel starvation wouldn't/couldn't have caused the problem I have?
It's just that I'm going up to Star Performance for a rolling road session and hope to have a good graph whilst the car's on song. Also to the fact that it's doing my head in cause I know that there is something wrong with my car and I don't know what it is! http://bbs.scoobynet.co.uk/mad.gif

Anymore ideas? Anyone?

In certain conditions under hard acceleration, in the upper rev range, it splutters/hits a wall before carrying on.

I had plugs and coil packs replaced but problem still happens intermittently.

I've been told this is 'overboost' but on the rolling road, we have been unable to re-create the problem. That makes it quite hard to solve.

I'd say check/replace plugs/coil packs as a first option and see how you get on.

Ben

Hi gordon,

I had a VERY similar problem and it was the air flow control sensor.
Not cheap, £200, do you have a warranty ?
Regards,
Andyp

Gussie Cup

That's what exactly happens! I'm not alone after all! Does Subaru dealers not have the facility to fault find via the ecu? Do you still have this problem?

Anyone else has had this problem?

Andy P

Incidently, I do still have some warranty left, but will that be covered? Will the coil packs be covered? What would happen to the air control sensor when I put a Blitz induction kit in?

Can the ecu adjust to suit the extra airflow
from any after market exhaust and intake mod?
I know the honda ecu's has a self adjusting mode,once the mods are done you just reset
the ecu and let it idle for 10-15 mins in turn senses the difference and adjusts the
a/f mix albeit a marginal difference.

[This message has been edited by kenny.c (edited 14 February 2001).]

Gordon,

Is it a misfire you are experiancing, or more like hitting a brick wall for a second?

If it is the latter, then it certainly sounds like your ECU is detecting overboost, and cutting the fuel. If your car is overboosting, then rolling road operator at Star will be able to measure your boost levels, if they stay below 1.2bar, and the cut out occurs, then your car is not overboosting, and the problem is probably a contaminated wastegate solenoid. This can be caused by filling your oil up too full (have you recently done this?), but normally only occurs on <98MY cars (is yours 97 or 98?).

To clean the wastegate solenoid, you must disconnect the T shaped hose from the solenoid, and spray it with brake cleaner. Then re-attach the hose, and go for a drive before the cleaner evapourates. This should clean it, and hopefully solve your problem.


If it is more of a misfire, then your problem is likely to be plugs/leads. What mileage is your car? My MY98 has just had the plug leads replaced at 53K miles, and it is quite common for them to require replacing at around this mileage.

Hope that helps.

SimonM
http://www.evosix.f9.co.uk/terzo.jpg

[This message has been edited by SimonM (edited 14 February 2001).]

i work at a subaru dealership and we found that the only way to cure the waste gate solenoid problem was to replace it.and i have never heard of replacing the leads that early .
a light misfire when you are in traffic and moving slowly can be caused by the o2 sensor so get it checked out.

SimonM/Scoobyboy

Thanks for your advice guys. Mine's only done 17K on a '98. SimonM, the thing you said about misfiring and hitting a brick wall, well, it's a bit of both. When it started misfiring, it wasn't as violent as a misfire, more like a stutter, and the speed was still gaining, but only slightly. But as I said before, it's only happened once and haven't had a problem with it again so far. And as for the wastegate solenoid problem, I think I'll need to take it to the subaru dealership to have it checked out cause I can't even tell the difference between a wiper blade and a wastegate soleniod! http://bbs.scoobynet.co.uk/biggrin.gif

I'm considering Kenny.c's theory. It sounds good but is it true? Anybody a Subaru E.C.U. guru?

Could it be a blocked fuel filter after all the crap was dredged up from the bottom of the forecourts' tanks?

Pete Croney saw a few like this, but I don't know what the symptoms were.

May be a cheap fix worth checking? Or if Pete sees this thread, am I barking up the wrong tree? http://bbs.scoobynet.co.uk/biggrin.gif

Chiark

Could be worth investigating. I'll probably wait until the Rolling Road session at Star Performance and see what they've got to say. But I'm still listening to the possibilities! http://bbs.scoobynet.co.uk/biggrin.gif

Gordon,

I have just re-read through your posts. How much fuel did you have at the time?

The 'spluttering' you describe could be fuel surge. I have experianced this, although only when going round corners.

If it only happened once, then I wouldn't worry about it as it could be something as obscure as bad fuel.

SimonM
http://www.evosix.f9.co.uk/terzo.jpg