moulsn306

Hi,
Have just bought my first impreza, a 96 2.0 sport, all i can insure, and it has developed a problem.
At 4000 revs it developes a major misfire, have changed plugs and coil pack but no difference at all.
Have had it plugged into computer and ecu is storing no fault code. Dealer answer wait until a fault shows or it stops completely, it could be anything.
Anybody got any ideas.

ScoobyDoo69

iTrader: (17)

When I had my sport I found the HT leads to be very weak, and misfired often, when replaced it was fine again..

Simon C

Has it got an the original cobra immobilizer (802t IIRC) on it by any chance??

My old 96 developed this problem, and got worse to the point I'd be driving it and it would cut out.

Cost me 1200 quid to find that out.

grahamk23

did you get it off ebay a few days ago by any chance??

moulsn306

Yes i did on sunday

moulsn306

Hi,
It could have will have to check it out

grahamk23

yeh i was looking at that but the guy wasnt right helpfull explaining my questions. he said something about headgasket replacment. hope you sort it tho, great car for the money.

Setright

Describe "misfire"?

moulsn306

up to 4000 revs it runs fine anything above its as though it misses every other spark cycle. the whole car jerks about not like just having a plug go down and losing 1 or 2 cylinders, it feels like the spark cuts then fires again. It can occasionally do this in 1st at around 1500 revs. hard acceleration is impossible. only does it under load you can sit still and rev it all day long never misses a beat. if you drive round between 2 & 4000 revs its perfect

mattyd

move your knock sensor onto a bracket on the gearbox

tis a common problem on earlier sports

check out www.imprezasport.net for a full "how to" guide

mattyd

Setright

On imprezasport.net you'll find you have to read a lot of my posts...be warned


What you are describing has indeed been "solved" by many with a move of the knock sensor, but I would never perform this mod on my own car.

You are in effect disabling the knock sensing system, and that can easily spell disaster for your engine.


I would STRONGLY recommend buy a new knock sensor from an authorised dealer. It will not be cheap...probably £80, but it is the correct way to solve your problem.

I bet your present knock sensor has a grey connector on it...the new one will have a white connector, to signify that it is the revised model. Moderately less sensitive, but CRUCIALLY not so easy to crack open the shell.

Clean the area underneath the sensor, and don't torque the new sensor to about 30Nm....is that 20ft/lbs??



YOU MIGHT, be experiencing a fuel problem. Running over Ron95 is a waste on these engines, and mine actually responds badly to Ron99...flat spot at 4K and 5K revs.
Replacing your fuel filter, BEFORE the knock sensor is an option you could consider, and at around £30 for a genuine item, it will be a cheaper place to start. Just make sure you let the car sit for a few hours before opening the fuel lines, so the pressure is gone.

If your knock sensor shell/housing is cracked (likely!) then you must replace it.

Setright

Oh..you'll want to reset the ECU afterwards.

Ignition key OFF.
Connect black and green connectors under the dash.
Ingition key to ON.
Throttle to the floor, lift it roughly half-way up, hold for 2 seconds, release.
Start the car.
Drive.
Check Engine light flashes in regular 1 second interval, no pauses.
Find a good place to stop the car.
Switch off engine, disconnect wires.....PRESTO!

grahamk23

wow...i never knew all that...

moulsn306

Ok Guys,
Plugs leads coil pack fuel filter all replaced knock sensor moved not a bit of difference has been made to the running at all.
Any more ideas

moulsn306

Also plugs replaced

moulsn306

Have found on moving knock sensor that it has the white connector so should be the newer model

grahamk23

if you send me your email address ill send u a manual which mite help u out...it has a troubleshooter part which mentions your problem

moulsn306

ok thanks nevillemoulson@hotmail.co.uk

grahamk23

funny email m8 but ive sent it for ya

grahamk23

wont send i need you to send me an email bravo16graham@yahoo.co.uk

moulsn306

Its been suggested locally that it could be the ignitor unit for the coil pack thats at fault, my question is does it have one thats seperate or is it built into the coil pack.

Twigs

I have this exact same problem with my turbo 2000, Ive also tried changing plugs, leads, fuel filter but its still doing it.
Im taking it to a specialist tomorrow to see if he can sort it. Let me know if you come up with anything, and likewise i'll let you know if he comes up with an answer.
It scares the crap out of you though when it misfires, the whole car jerks!

moulsn306

I totally agree its like sitting on a jack hammer and you wonder whats going to break next. Stupid thing is mine was just tested on wednesday with this problem and it passed the emissions with flying colours. Am begining to think its maybe a sensor somewhere that is breaking down. All i know so far is its not the knock sensor maf plugs leads coil pack or fuel filter and the test rules out lamda sensors. Not a lot left to go at now. Booked it in with local auto electrics wizard on wednesday but the fact it only does it whilst driving makes it difficult to diagnose.

moulsn306

Ok Latest update
Now fitted new knock sensor air flow meter crank and cam sensors. Not made one bit of difference to it. Now skint after all that lot and still a car i cannot drive.

Setright

What about fuel?

Which fuel are you running? Have you been able to drive enough to empty the tank?

As I said, mine misbehaves on 99Ron.



Try topping the tank up to the brim with a good 95 petrol (Shell/BP) from a busy station to be sure you get "fresh" fuel.


Did you follow my ECU reset instructions?

moulsn306

Hi,
Yes i managed to empty the tank and refill it at a busy station, and yes i also followed the ecu reset instructions and again today.
Am beginning to think is this electrics or is it starving itself of fuel for some reason. The only thing is now, that has changed after all this, when engine is cold and choke on it still does it but not half as bad as it was, but once warmed up it is just the same as before.

grahamk23

im guessing this is getting daft now...you need to take it to a mech man coz your throwing money at it and getting no where..the guy mentioned something about the head gasket and a replacment engine...ill have a look on my ebay messages.

Did that manual help at all??

moulsn306

Hi yes it helped thanks. Car has had engine replacement yes as headgasket went on old one, and garage wanted fortunes, so claimed fresh engine cheaper option. Already had it to the local scooby dealers plugged into computer no codes no ideas just pocket £100 lighter and told come back when it breaks then we can fix it. It has been suggested by a local guy that it may be the fuel pump that is weak and when not under pressure and just reving will deliver but when driving is breaking down. Other than fitting a new one how you gonna check that. I cannot see it being electrical now there is nothing left to change.

grahamk23

he could be right there because theres no load on the engine therefore not much fuel. you cleaned the injectiors??

moulsn306

Ok heres the latest,
Took it to the local rally guys, they bypassed the standard pump and tank and filter, put in a different set of injectors, checked out various electrical readings. The answer was there is nothing wrong with it everything checks out fine so there is no reason it should be doing what its doing. The theory they have come up with, is its an electrical problem somewhere within the loom and a joint or wire is breaking down. Its in at the auto electrician tomorrow for him to have a look see what he thinks. He has had one similar and took 3 days to find a nick in a wire casing at the back of the engine, a bit of insulation tape that one was fixed. Fingers crossed