Hello ,
I am brand new to this forum after buying a 94 impreza today. Only thing is i have a major problem. Firstly let me say the guy lived in New Malden and i test drove it on the A3 , although i overtook a few cars and the car seemed to run well there wasn't much room for me to really open it up.
After buying the car and driving halfway home i decided to see what it could do , but as it got to 4k rpm the car just jerked like crazy and wouldn't go past 4k rpm . My girlfriend was following in her car and said the exhaust seemed to shake a lot every so often (most likely when i hit 4k)
By the time i got back it was pitch black and not the best time for me to go and inspect under the bonnet.
My first thoughts were either the turbo , but it sounds like its operational below 4k , there is either a bad split or bad connection in the rubber inlet manifolds or the exhaust manifold is not connected to the head/barrell properly
I just wondered if an imported '94 would be restricted through the CDI ? i can't see that this is the problem as no manufacturer would have a car jerk like that through restriction.
I would appreciate any help you guys can offer
Thanks for taking the time
Alex

 

Hello & welcome to the forum
If the car is hesitating as soon as maximum boost is reached it is likely to have a problem with either the spark plugs or the coilpacks, the latter tend to crack around the ends under the rubber shroud causing them to break down (especially on boost)
The JDM imports are using restricted by speed in the ECU which normally happens around ~ 110 - 115mph which can be overcome by either a cable convertor or by 'chipping' the ECU

Cheers

 

Thanks a lot for the help. I will change the plugs first, if the problem persists i will sort the coilovers. Would you have any idea where would be a good place for me to get them and how much can i expect them to cost? Also is it relatively easy for me to change them myself ?
Sorry for all the questions

 

The Classic Impreza has a Coilpack per plug instead of a coil and distributer. The coilpack sits on top of the plug itself and is retained by a bolt - to access the plugs the coilpacks require removing which is made easier by removing the airbox on the drivers side and some of its ancillary pipework and the washer bottle on the passenger side.

Cheers

 

Is the car modded at all? Does it have a de-cat exhaust? If so, you could be hitting the factory boost cut. Check the coils first, although if it were a coil I would expect a misfire across the rev range and lumpy idle.

Nathan

 

Not necessarily true - most run fine until any boost is made and begin to 'buck/kangaroo' as the spark strength weakens. The coilpacks/spark plugs are also the main suspects when modifying as when the boost is raised these when faulty or damaged highlight the same problems

Cheers

 

Hello ,
Just to clarify there's no minor misfiring in the rev range but once it hits 4k thats it the jerking the car makes is so bad you HAVE to change up , it can't be driven through to 5k. I should have time to have a look under the bonnet and start eliminating tomorrow.

 

just to add it does idle high , about 2k until you blip the accelerator this is what led me to think it could be an airbox problem

 

Hello again,
Just got round to changing the plugs and the first coilover i took off had plastic falling off the ends. So I will be getting new coilovers.

 

IWhen you say "jerked like crazy", was it a total on/off feel? If so and it only does it 3rd,4th and 5th on full throttle it could well be over boosting and hitting the fuel cut. If you have a boost guage you should be able to see this.

Cleaning the boost solenoid will probably cure this. Do a search on here for all the details.

 

Its in every gear, but its worse in 3rd up to 5th. This does sound likely though as i wouldn't understand 4 plugs firing fine then all giving up all at once. I have a Subaru dealer round the corner so i will be paying them a visit in the morning.

I have just searched amd found several posts on what sounds very similar. Its a very hard jerk , the car won't go past 4k. It does feel like 200bhp has been lost. It also surges at 3k but goes through it, you can hear the turbo whistling so my first thoughts are that it isn't the turbo. Where do i find this boost solenoid to clean up ?

 

If you have found a coilpack damaged then it is likely that the others maybe too as they were probably all fitted around the same time therefore have endured the same amount of heat variation so could have hairline cracks in the ceramic at the plug end. One coilpack alone breaking down will significantly effect the running/power especially under boost conditions

Cheers

 

Thanks for all the help. I have been quoted £35 each coilpack so £140 in total , something i can change myself, but i wish i knew for definate which direction to go in. I don't want to fork out £140+ and the problem not be sorted.

 

Hello ,
I have just read a few posts on this forum and think i need to add some more information. The three main problems with the car at the moment is the "4k jerk", the speedo doesn't work and "Check Engine" warning light is on.
I have just read a post by another member saying that his speedo doesn't work and its now causing his car to be on "limp home". Could this possibly be the same ? Could mine be set to "limp home" as the speedo isn't connected properly?
Where does the clock read the speedo from? Front Wheel? Crank?
My main Subaru dealer has requested i put it in for a "diagnostic" check which costs £40 and i will have to wait till Friday to have this done. Sorry if i am waffling on a bit, but i'd rather know 100% what i am dealing with before i go ahead and spend out and still have the same problem.
Thanks a lot for those being patient with me I am impatient as i don't want to drive the car until i know its 100% and don't want any other damage to be caused by driving it like this.

 

with the speedo not working it will cause the check engine light on and would put it into limp mode.
Under the bonnet, if you look toward the gearbox dipstick you will see (or should see) a cable going down towards the gearbox, this is where the speedo reads from. On my car (my93) it is loose and quite easy to catch it which will stop the speedo working. (did this when my car was being mapped good job really as the speeds would have been scary! - private airfield of course)

 

Well i now have a working speedo and speedo cable fitted thanks to a forum user.
But i'm still have major trouble.
The "Check engine light" is now flashing instead of being on constantly
The car when cold hits a brick wall at 4k like its trying to put my face through the windscreen, when hot it goes past 4k (sometimes with a slight mis-fire)but has no enthusiasm. The power up until this point is amazing but then it seems to drop dramatically.
As this is an import and has no information on work done to it, how would i find out if it has a de-cat pipe (Back-box is HKS) or if its still restricted via the ECU. If it is restricted where is the best place to get an ECU chip ?
I'm fairly sure i should have followed peoples advice and fitted new coilovers, but i now seem unable to find any and can't find the search option on this site to find information on cleaning the boost solenoid.

This is my first Scooby, and up until now have only owned Pugs, and was fairly sure Impreza's were bulletproof. It seems i have bought a right heap, with problems coming out of its ears but if i can sort out these problems i would like to sell this, and get a better example.
At least in future i will be more informed to problematic area's and know what to look for.
I'm sorry to those who have already advised me and have chosen to take another route.
Anyone who can help please please do
Thanks a lot
Alex

 

Hey there...
I've just scanned through the topic and thought I'd throw a few ideas your way.... Sorry to hear that it's not going to well so far...
Firstly, does the car have aftermarket boost control? Does it have a boost gauge? If so what's it boosting at? The reason that I ask, is that you could be experiencing fuel cut if the boost is too high.
Next, there is an ECU reset procedure somewhere (I don't have the link handy, but won't be difficult to find after a quick search..) which also includes the codes for the CEL flashes - so it'll tell you if the ECU has recognised a fault in the system and tell you what it is.
If the coilpacks are fractured, they NEED replacing. Otherwise you will be chasing your tail with fixing/ replacing other componants. Try eBay or search the net for Scooby breakers if you're on a budget.
I wouldn't give up just yet, it sounds like you have a couple of problems that could be causing all the symptoms.
You should be able to tell from a quick check whether the cat is still fitted and with regards to it being "restricted", the usual method is to put a speedo cable converter on Ver I & II WRXs which places the speed retriction at 180mph..... Oh, and to clean the boost solenoid (assuming that it's still being used) remove it and flush through with carb cleaner. Let dry and reinstall.
I'm still learning myself (I've had my 95 WRX for just over a year) but hopefully all the info that you need will be hidden in these forums somewhere - I've found them to be invaluable.
Good luck, let us know how you get on.
Moss

 

My first thought when skimming through this was a boost solenoid and pipework full of oil. It happens. Clean out your boost solenoid before doing anything else. It costs you nothing. If you don't have a boost gauge, get one.

 

Thanks a lot for the help, boost gauge is now on its way and coil packs shouldn't be long either. I took the car out for a long journey today and noticed a warning light coming on when sitting comfortably at about 90. It looks like 2 pans facing each other with heat waves above them lol quality description i know . Its about 3 warning lights left of the "Check Engine"

Red Scoob - an ECU reset procedure would be fantastic if you could find that link for me please m8.
I'll get there, I'm deterined to, i just wish i had experience with Scooby's rather than be a complete noob.

 

Here you go, mate.
http://www.derekcarswell.pwp.blueyon.../pages/ecu.htm

 

That is the cat on fire light. Dont know what it actually means though when it comes on. Someone can probably tell you.
To be honest and in my opinion, I personally wouldn't drive it at those sort of speeds when you have a problem with the car

 

Just found the 2 black wires, they were already connected. Disconnected them, switched the ignition on and the light comes on until you start the engine then it goes off and stays off . Reconnected them and switched it on again and its a constant flash of 0.5 secs , not a certain number but it continues until you disconnect them again.
Unless i am reading this wrong, this means there isn't a problem. And the flashing i was getting was down to the wires being constantly connected.
If i had a choice i wouldn't be driving it at all, 90 was kmh not mph i had my 2 kids in the car so wouldn't have been doing 90mph.

 

Sounds like someone forgot to disconnect them after a reset.
Just to confirm (in case you're in any doubt), those wires (and the green connectors) should not be connected for day-to-day driving. They are for diagnostic purposes only.
So, is everything sorted now?

 

No its still missing, hopefully the coil packs will sort that

 

If you look at where you found the two black connectors, there should be two green ones. Connect those and switch on the ignition. Things will start to happen like, the fans will cut in and out and you'll hear a clicking sound from the driver's side suspension turret. This clicking will be the boost solenoid operating. Once you've located it, pull off the pipes and squirt brake cleaner through it.

The 'brick wall' you're hitting sounds like fuel cut on over boost due to oil in the boost solenoid. Flush the pipes too.

Switch off, disconnect the green connectors and try it again.

Don't overfill with engine oil or it'll find it's way to the solenoid again.

HTH

 

Flushed the solenoid with no change . Does anyone have a reccomendation for where to fit the pipe that connects to the boost gauge ?

 

ye its the first one on top of the manifold closest to the throttlre bodie. your problem does sound like the coil packs. have you checked them for cracks around the crown. take each coil off and take the rubber end off. if there are cracks theres your problem. as a temp measure, put some insurlation tape around each coil pack and replace the rubber. you say you changed the plugs to. which plugs did you use, these cars dont like champion & any other cheap plug. the other only option is to check to make sure all the vacum pipes are corect. this is what i found with my car. i had a boost problem at 4k, but my problem was the fuel presure. it was low. so on high revs felt like no fuel. well hope any of this helps. good look

 

Hello,
Thanks for all the help its really appreciated. I have fitted the boost valve after searching about for the best place to fit the T piece and tubing. Its on the first pipe from the inlet on the right as you look down at it. Its registering -0.5 bar when idling and reaching + 0.5bar when above 4-5k or so. Is that a normal reading ?
Am i correct in thinking a boost control valve isn't neccassary on an impreza ?

 

Up

 

You need to fix the speedo to stop it from dropping into limp him mode, it may also limit the RPM to 4000. If the car is missing badly enough to cause some detonation, the ECU may also see fit to put it in limp home mode.

In short, fix all your known problems before trying to get the car running properly.

Paul