MY CAR HITS A WALL AT 3000-4000 RPM HELP PLS
 

THIS IS MY FIRST IMPREZA I HAVE EVER OWNED AND I PURCHASED ON A MEMBER ITS A WRK 1994 STI NUMBER 25 OF 100 MADE (YOU MAY KNOW THE CAR?)

WELL IT HAD AN ENGINE REBUILD BY API AND EVERYTHING SEEMS TO GO A1, UNTIL THIS WEEK, WHEN THE CAR BOOST UP AT ANYTHING BETWEEN 3000 AND 4000 RPM ESPECIALLY IN 4TH AND 5TH GEAR THE CAR FEELS LIKE IT HITS A BRICK WALL AS IFF NO FUEL GETS THROUGH THEN THE CAR GOES AGAIN, IT IS ONLY FOR A SPLIT SECOND BUT I AM VERY WORRIED PLS HELP ME FIX IT

I HAVE BEEN ADVISED IT MAY BE THE O2 SENSOR OR LAMBDA SENSOR?
PLS HELP IVE ONLY DONE 600 MILES AND I FELL BUYING AN IMPREZA WAS A BAD MOVE?

hi mate,
how many miles has it done since the rebuild. Had exactly the same problem on a STi-3 i went to look at - had done 1200 miles on a rebuild and around 4000rpm in 4th and 5th it was like it just cut out and wouldn't pick up any speed -
Needless to say i didnt buy it as wasn't too sure if it was a big problem or not, or whether it was related to the rebuild - maybe it was not run in properly.. Do any 'check engine' lights come on when it does this....?

Cheers

Try not to worry, any car can need a sensor replacing. It's never a bad move to buy a Scooby!

I'm sorry to say i don't know what the problem might be although this is a very good site and i'm sure someone who knows will be along soon!

If you know the username of the person you bought the car from you could search their posts and see if they knew anything.

Id be checking ALL the pipes under the bonnet , make sure one has not come off ,

THANKS ALL FOR THE HELP I WILL GET A NEW O2 SENSOR TOMORROW AND CHECK ALL THE PIPES LEADS ETC ETC THE BLOKE I BOUGHT THE CAR WAS VERY GENUINE AND HE HAS BEEN VERY VERY HELPFUL PLS KEEP THE IDEAS FLOWING.ANYBODY KNOW WHERE I CAN GET AN O2 SENSOR FROM APART FROM SUBARU?? :)

You are getting fuel cut as the turbo spools up. It's highly likely there is a pipe out of place on the boost control system, or that it's been modified with a bleed valve or such. The standard STI 1 is very aggressively mapped, and you would do well to get it sorted before it blows up again. In the meantime you should drive off boost, ie don't give it full throttle allow the boost to build up to it's maximum. If you keep it to 3/4 throttle max it should allow some power without triggering the fuel cut.

Paul

Edited because paul can type faster than me :D

also could be a missfire caused by a dead plug or could be a coil pack breaking down you can check to c if the end of one is cracked if it is it will short to earth,

MAF Sensor

pavlo is right. fuel cut.

Which i failed to explain the reason why. The factory STI ECU has a raised fuel cut level of 17.2psi (of boost) as soon as you go over this level it will cut the fuel in order to prevent the boost rising any further and blowing your engine.

A 94-96 UK car and non STI jap car has the cut set at 15.4 psi.

Do not do anything to raise the fuel cut until you have confirmed the car is running right on the current ECU map, as the STI 1 is very prone to detonation when running on UK fuel. Given the car already has one rebuild under it's belt, I think it's fair to say that something needs tweaking, or you should be using a healthy dose of octane booster.

Paul

This car was overfuelling like crazy when we had it here. The oil in the sump was 50 percent fuel and it lost the bearings on the crank. The previous owner of the car knew this and as far as I am aware was getting it looked at by Andy F.

I would suggest however, that it might be other things rather than fuel cut, which is certainly an option, don't get me wrong.

Run a diagnostic on the ECU by joining the loose black wires together down by the steering column / pedals area [ there is a link on here somewhere with a full set of instruction on what to do and how to do it. BUT I'm decidedly untecchhie about that sort of stuff, so another Snetter will link it for you.

Depending upon the result of the test will tell you the potential fault.

It may even be something simple like a busted speedo cable.

CERTAINLY, get it found and fixed or you will create problems with the engine.

Good Luck David API Engines

Okay, that's useful.

In that case you DEFINITELY need to get teh ECU looked at, fuel pressure turned down or something. If it's still overfuelling as much as David suggests then you you just be getting a rich misfire. It's not mega serious on it's own, but after time (weeks no months) it can do some serious damage, wearing the bores, diluting the oil etc.

I would suggest you get it somewhere where someone with some genuine Subaru expertise can take a look at it.

Where are you based?

Paul

the car runs on shell optimax as david at api told me to run it on this, the car has a scooby ecu on it so it shouldnt need a booster as the previous owner told me it will run all day long on 97/98 octane fuel. Ive got the car booked in at AS Performance so i can have the ECU checked and maybe get the car set up and the fuel pressure ets checked,

as i am new to all this and new to impreza what do you all suggest i ask the garage to do apart from "sort thie problem out".

thank you all for the help!!!!!!

Thought I had better jump on here and have a look after your call tonight Stuart.

I was the last owner of the car and I have never hidden anything about it. I loved the car and spent a **** load of money on it. If circumstances hadnt prevailed then I wouldn't have sold it - I'm the person who runs the website register for them, so it wouldnt look good to have a shabby mota, now would it? And the LAST THING I want is for the new owner to have any problems with it. I wouldnt like it, so I wouldnt do that to someone else - especially over this car.

For everyones information, the rebuild was by David earlier on the thread as he states - I took his advice being as he is a proper 'Subaru expert'. David - I also sent the link a short while back about 'how to' do the connector check and how to read it;) Thanks. And yes, your advice was taken however you cant do much in 600 miles other than change sensors I'm sure you agree.

The MAF was replaced thank you, as was the throttle position sensor and lambda sensor. The car was checked over many times with the Select Monitor by an ex-Subaru mechanic and myself during the 500-600 miles of run in whilst I had it. It never displayed any faults at infact when first plugged in showed that all the sensors above were top level of their limits. Hence this confirmed much of Davids advice so they were all changed accordingly. After this reading were all perfectly normal. Oh, and the car does and did not have a misfire at all either before of after engine failure. No problems starting or driving either.

The part I couldn't do was get the car remapped as circumstance forced sale sooner rather than later (baby on way for those doubters). I took £250 off the asking price to ensure that this was carried out by the new owner - thats the part I've been stressing many times from pre-sale till on a day or two again (I have numerous PM's advising this) - Stuart I'm sure you'll back me up on that one. Basically we went dutch on a remap:D

Pavlo - you actually did the ScoobyECU fit for this car. I did send you a mail to ask if you would at the ECU again after the failure. No reply. Incidentally, OB was used pre failure Millers OB and that was one of the reasons I wanted the ScoobyECU, so that I could run safely on UK fuel as it mapped for 97. Never had anything else other than optimax.

I have supported and advised Stuart since day one - also suggesting the o2 and det can check at 1K as well to make sure all good - remember it was sold at 600 miles. Dont know if this was done or not - Stuart can confirm either way on this?

And for extra information - Stuart did say the CEL light came on briefly at one time (i think) but it went to a garage and all was supposed to be ok.

Incidentally, I've also previously also advised getting the lambda changed, driving off boost driving until fully run in and then the remap (however the lambda is worrying especially if its failing/failed again (since its only about 3 months old).

Cheers,
Mark
Proud Ex-owner of No. 025

Thanks for the post mark and can say that you have supported me all the time and i am not having a go at you or the car i bought the car as seen and as it is my first impreza i am only trying to get advice. The car is getting re-mapped but i have been adviced not to get this until the car is run in (SOMEBODY GIVING ME BAD ADVICE I DONT KNOW BUT IF A GARAGE SAYS IT NEEDS A REBUILD WHEN IT ONLY MAY NEED A SENSOR THEN I WOULD TRUST THEM) Thats why i am trusting you all on here to help and i am not trying to slag you off you have been a great help.


I would also like to say that i have never been above 4000rpm i had the car serviced 400miles ago taking the running in to 1400 miles since rebuild. I allow the boost to come on slowlly as this needs to be so the rings bed in. I do not thrash it it gets shell optimax all the time.

I just need advice on what to do not how to drive MY car.

I have just done the computer check and these are the fault codes
13= Cam shaft position sensor
45= Pressure sensor - pressure exchange solenoid valve.

what do these do i havent got a clue? can i fit these? and where is the best place to get?

AFTER GETTING PROPER ADVICE I WOULD LIKE TO CONFIRM THAT THE RE MAP WILL TAKE PLACE NEXT WEEK!!

THANK S ALL AGAING FOR ALL THE HELP AND SUPPORT.

LOL!! No worries Stuart - glad to see you posting on here (finally ;) ) I just wanted to elaborate on some information so people get a better picture of whats done. Although I admit I'm just concerned that people might think I've sold you a duffer when its absolutely not the case. And I know your not having a go - I expect you'd be on the phone first.

Thats cool about the revs at 4K - would never dream of telling you how to drive your car (I mean your an Ex-BMW driver :D;) ). Its not like we've not spoke and written a fair amount of times about how to drive the car ;)

I'm the same as yourself, you have to trust the opinions of the experts at times - and I always worry about the 'getting ripped off' scenario as well. Especially in Subaru world its easier as the costs are so much dearer than other marques.

As for these 2 faults/sensors - I'm totally in the dark, so much I dont even know where they are on the engine:( Anyone help out here?

The SN folks are a good bunch - you just tend to get every fault scenario when you post a fault, and that can be a hinderance more than a help at times. The best thing is to try an detail exactly the fault to try narrow down the replies (if anything).

Take care,
Mark

PS thats excellent about the remap :thumb: - atleast then something positive will happen and you'll know what exactly is going on.

I really should learn by now - I remember spending ages looking for the connector link and found it my mate Dereks site. Well I tried this first and guess what - a piccy of the engine sensors:D

Hope this helps atleast alittle.

http://www.derekcarswell.pwp.blueyon...%20sensors.JPG

No.2 and No.12 in the picture is what to look for.

One must be under the oil filler cap. The other looks like its up at the boost solenoid (or is the boost solenoid?).

Sorry not much more help I'm afraid.

YET AGAIN MARK YOU HAVE SUPPLIED THE GOODS AGAIN I CANT THANK YOU ENOUGH (APART FROM YOU SELLING ME THIS GREAT CAR). I EXPEXTED A FEW NIGGLE PROBS WITH THE CAR WHILE IT SETTLES DOWN AFTER THE REBUILD AS PER NORMAL IM GONNA GET THE GARAGE TO CHANGE TH ETWO SENSORS AND I WILL HAVE THE BILL THEN AT LEAST HOPEFULLY IT WILL BE DONE WRIGHT. I WILL PM YOU WHEN THE WORK HAS BEEN DONE NEXT WEEK AND HOPEFULLY IT WILL RUN LIKE A NEW CAR AGAIN.

THANKS MARK AND SOORY TO CALL YOU AT HOME IT WONT HAPPEN AGAIN. I HOPE YOU STILL HAVE TIME TO POST ADVICE ONCE YOU ARE A DAD.

GOODLUCK AND THANKS
]

Does it have a boost gauge on it?

Remap does sound essential on the car but TBH firstly all the sensors on the car HAVE to be functioning correctly before looking at the map. Chances are that a sensor might be causing the car to run rich due to being faulty.

Ideally get it plugged onto a Select monitor for piece of mind but TBH the camshaft sensor isn't anything major.

The engine from David @ API will be an excellent rebuild and you will be very pleased with the results. And well done on running it in ;)

Jon.

I had a problem with my 93 WRX a few years ago where the Manifold Air Pressure sensor went duff (Sensor #1 in the diagram) and I had fuel cut when the engine came on boost - not a nice feeling!

The local Subaru garage wanted £200 for a new one, but I ended up getting one from GradeA Subaru for £30, and it's still working fine.

I *think* the fault code was 45, but I stand to be corrected. Either way, sounds like a (relatively) simple sensor problem.