Maf or lamba as they control fueling which in turn effects emissions.

I put a post on earlier on how to test sensors via multimeter.

Give it a go then u'll know for sure instead of just guessing.

 

well... ive been told that the subaru wiring is pretty high tech and if im not getting any fault codes come up on the ECU then it has to be a mechanical problem. something like a split pipe.

i would have guessed coolant at first but that wouldnt explain it struggling and shaking when cold. thats why i was thinking lamba due to emissions being high. but then im not getting an ecu code for it.

my hwhole engine bay is covered in easy start as ive been spraying it everywhere trying to find a split but nothing. stood still it will rev up lovely when warm and nothing wrong.

 

ok cool but shouldnt i get a ecu code for that?

 

As said previously, I had problem with my lambda sensor an irritatingly no cel code was displayed. I had in diagnosed by a local motor electrical technician, it cost me £100 but I was lucky as this sorted it out first time. The cel is good at registering faults, but its not perfect.

 

as above, the ecu is good most of the time, but its not by any imagination perfect, at the minute i think i have fried the main relay, which means some of my sensors arent getting power, out of the 4 sensors i know have no power, only 2 are showing codes.
Not only that, but the lambda might be putting out a voltage thats in limits but way off for what you want.
the lambda, MAF and coolant temp sensor are the ones that control fuelling and timing, they are easy to do, and to get hold of.
i would start with the MAF, my lambda was fooked before, along with my coolant temp sensor, but it drove fine, just drank a hell of a lot!!!

 

I'd second mikey2 suggestion of the coolant sensor. I've had a few cars now that due to this going u/s, caused all sorts of juddering, power loss, rough running.

Couldn't tell you where it was on these engines yet, but it's a quick test surely. Usually locating it, disconnecting it when the engine is warmed up should make a difference. If not, then it's not that component. Could still be the cabling to it though.

 

the sensor is a brass colour to the left of the intercooler as you look at it from the front, its near the turbo outlet, on the block, easy ish to see from above.
Good luck taking it off when its hot though, rather you than me!!!!!
its a bit of a tit to get to at the best of times, have lost most of the skin on my knuckles trying to get the plug off.
They are about 30 quid from subaru, so not that much really.

 

ok so you really think a coolant sensor could cause this much hassle? i spose somethin must be telling the engine something is hot when its cold i spose.

i have a front mount intercooler so will able to access the coolant sensor easy.

i was going to get a volt metre from work on monday and use it for a few days to check sensors. does anyone please know what readings i should be getting though. i can test the readings i get but dont know what to test them against really.

 

http://www.jimclarkeracing.co.uk/sco...iagnostics.pdf

 

If the link does'nt work just cut/paste it into google.

you may need adobe or simillar to read it

It has all the info you will need on testing sensors

 

thats a good website thanks. bit complicated but ill try my best to see if i can find something wrong. thanks alot.

 

dude, my opinion its your plugs , try a set of the original plugs , before u went one step colder, Its the cheapest alternative to see if your new set is the problem .GO BACK TO PFR6b

 

ALSO HAVE A CHECK OF YOUR FUEL PRESSURE !!

 

the plugs are not the problem. i only changed the plugs to see if it would make the problem go away.

 

Did you gap them correctly 0.7mm. I have 7s in mine, changed up from 6s, gapped them to a tight 0.7mm and have no probs. Just a thorght

 

no they are at 0.8. car is in garage at the moment.

so far he has fitted a new MAF to the car to test it and found that my kangaroo when cold has now gone and it seems to boost fine through all the gears again.

unfortunatly he did ask me, has the car ever cut out on you completely and i said no never. so he thinks he now made a new fault as the car has started completely cutting out now lol.

he thinks there is deffonatly an electrical fault with the car but he doesnt know what it is and may take for ever to actually find it.

 

Check your battery and charging circuit, my sister had that problem on her car and it turned out to be the battery was knackered and the first thing the ecu killed were the injectors. Glad its running now, thats a god step in the right direction. You can do what i did with the wires, get it running and poke all the wires and see if you can get it to stall.

 

poke what wires exactly? its a brand new battery. i only fitted about a month ago.

the problem was sort of there but not as bad, had dodgie battery on the car. with a dodgie battery the alarm would beep when i started the car in the mornings, found out this was a warning sound with the sigma m30 alarms to tell you the battery had a problem.

I went on holiday for 2 weeks and fitted new battery when i got back. car was ok and bleep noise from alarm stopped.

The problem with it kangarooing got really bad about a week later, then i changed oil and coolant and it made it 10 times worse. this could just be because the weather temps had dropped alot for the next few days.

i havent driven the car its still at the garage so im not sure how often the engine cut out is happening, he told me once but that might just be a freak cut out due to me driving soooo long with a dodgie maf the ecu needs a reset.

I did check the voltages on the MAF and the diagnostics diagram somebody sent me on here and everything was fine. only thing i can say is that in the manuel it shows only 3 readings for MAF and i actually have 4 wires with voltages so the 4th wire had a charge of around 8V but dont know if this is ok or not???

 

ok i thought after reading the above i would add my story, i have 94-2000 uk spec impreza,my problem started a while back early dec last year,is an intermitant starting idle fault, not all the time prob 50 % time. engine fires up and struggles to hold revs,engine check light pops on and as this happens the hissing noise from engine goes( restriction on air intake)??? after 3 attempts the problem appears to improve then holding its revs and so the car then runs fine,slightly less power than used to have , but hey theres 160,000 miles under its belt so to speak.if anyone can suggest a poss cause?? i read it could b maf? lamba? coolent sensor? air solenoid? split pipe? i had bmw and on its last legs it developed the same fault.i think it appears to b fuel air mix as heart of problem , like choke related? - i dont know........... )

 

Woody, its the main wiring loom that needs the poke, doesnt matter how or where, but thats how i found my problem, with the use of a multimeter too though, you can find if any wires have shorted together or if a wire is broken, as for the MAF, i dont know, i havent had to look into that yet, but i can have a look and see if i can find something for you. when you say you had 3 readings, where they resistance readings or voltage??? there might be one feed one earth and 2 signal wires, but dont quote me on that!!!


AS for the the other problem ste, i would check your error codes when it does it, should give you an idea of where your problem lies. It could be any number fo things, but a code would give you a starting point.

 

sssssteeeee if your check engine light pops up then just check the error code your sorted then, atleast you get a check engine light my ECU thinks my car is fine.

mikey2 when you say main wiring loom do you mean to the ECU or to the main resister box under the engine or down by the drivers feet?

with the maf i had power, signal and ground all in the right voltage ranges. then i have a 4th wire which isnt in the manuel but has a voltage reading of around 8 volts but does move up and down alot. not sure if thats good or bad as i dont have anything to check it against. i just used the website somebody gave me earlier in this thread.

 

i mean any wiring in the engine bay mate, something is either not working, or not working right, its a pain, you just gotta prod some wires and hope you find something. I dont know about the MAF to be honest.

 

ok ive just spoke to the garage. he has told me that the car runs fine at idle and everything is ok apart from one little problem.
when you belt it at around 5 6 rpm the rev counter goes to 0 and the car kicks back like you have hit fuel cut. its not hitting fuel cut its some kind of electrical problem. after a second or so the revs come back up to around 4rpm. the engine doesnt actually cut off the rev counter just drops to 0. NEVER happened to me before though.

all he has done is replace the MAF and it fixed the idle problem and boosting funny. now it just cuts out like fuel cut on full boost but he is sure its electrical.

 

with the rev counter going to 0, i would defo be thinking electrical, and sounds like the ecu is going into safe mode, restricting your boost and rev limit, i would check your codes again, if lots then clear the ecu and check again when it does it. Maybe you are over boosting a bit and the ecu is having a paddy, as far as i know the revs are taken from the ecu to the dash. I just hope its not a wiring issue between them, cos thats a right pain, its dash off an everything.
Does it only do it at 6k? or does it sometimes go over, or can you accel gently to 6 k wothout coming on boost. Try the same revs with different boost, controlled by your right foot.

 

Limp mode is 3500rpm iirc

 

i havent driven the car yet as its still at the garage. it NEVER did this to me though so im not sure what they have done. i did give them a boost gauge to fit so maybe he has wired that wrong. i told him to use the feed from the stereo as it has a constant, earth and ignition power, which is what the gauge needed.
i have got alot of electrical stuff in the car like double din dvd player, freeview box, and drop down monitor in the back. they are all sharing off the same power feed. maybe chucking a boost gauge on there aswell has blown something. also i added everything after a large fuse that goes to the head unit. maybe he has added the boost gauge before it and its blown another fuse along the line. not sure cos i cant go see the car as the garage is miles from me and i have no car lol.

easy way to check it out i spose is to cut the earth and power wires at the beginning so its all dead and go for a drive then see if its ok.

as far as i know it only happens on full boost at around 5-6rpm. he did ring me the other day and say it cut out at idle and the revs dropped but he said it has only done that once. hes been driving the car around yesterday and said all was fine till he really belted it. the revs do go higher but only if you dont use full boost.

 

did the guy at the garage say that the speedo reading dropped as well?

I cant remember page one now, but if its an import and it has been fitted with a convertor/delimiter (the type that fits on top of the gearbox), then there is a possibilty this has been knocked and is loose. The result of this is that if you go over any bumps etc it can temporarily lose connection and this gives you the zero reading. Also what will happen is it will put the car in limp mode giving the cut that you experience. Once the engine has cut, the jolt can then reseat the connection therefore running fine again. Worth a check as it wont cost anything .

 

Aiiiiii, tiz true, my cable came out of the back of the clock after i disturbed it routing the boost guage pipe, no speedo reading and put me into limp mode, i got the CEL on too, reinserted cable, reset ECU and all was fine. Well worth a check

 

my car is still running in km and is limited. not sure how he has fitted the boost gauge. maybe he has thread it through the dash and knocked something off them. i will give him a ring tomorrow for an update and mention it. this has never happened to me before and i havent even seen it yet, sounds like something he has done.

he did ring me and say "erm.... has the car got any kind of electrical fault? or is it just the problem with running rough when cold you wanted fixing? has the car ever cut out on you when its just idling?"

i said "what electrical fault? nothing is wrong with it is there? it just kangaroos when its cold? starts first time everytime and all electrics are fine"

 

ok i spoke to garage today and he says basically the car is all fine and dandy until you nail it and get upto around 5-6rpm on full boost and then the whole car will cut out. like somebody has ran along next to u and nicked the keys. he said if you coast for about 10 seconds then it suddenly kicks back in again.