smeddle

Just bought a mint my00 uk turbo in mica red, i absolutely love it, done 69k and is a minter,
The only thing is when i was driving it home last night, at 4k revs it stutters just for a sec then carries on without any fault, literally for one missifre or something, what can it be? a sensor? the engines mint except that, cars been really looked after, is this serious? always a 4k in any gear, one little engine stutter?

Please help, its not bothering me that much, just want the car runing 100% and its a small niggle,

But yeah its my first scooby, just sold my mk4 golf v6 4motion, but i love the scoob, looks top notch an handles sooo welll, i just love it,

Also dose any1 know whats happened to the south west scooby club, i want to join, i live in devon and would love to be part of a club for weekeds etc.

Cheers

Sam

smeddle

Its like a slight hesitation bang on the 4k revs!

Splitpin

We can't tell you whether it's serious or not, especially on the basis of information given - we clearly can't diagnose your engine via a remote connection over Scoobynet.

Yes, it may be a sensor, it may be something else. It may be inconsequential, or it may also be a symptom of a problem that is a lot more than a "niggle".

The short answer with issues like this is always that if you want a quick fix, the quickest, safest way to get it is probably to drop into your nearest Subaru specialist (or tidy main dealer) and ask them to diagnose it for you. The obvious candidate for this would be Enginetuner in Plymouth.

It we're going to be able to give you any more pointers, it'd help to know a bit more about the nature of the problem. Like, for instance, does it happen only under hard acceleration, or only under light acceleration, or does it get worse the harder you accelerate?

Also, what happens if you try and hold the engine at the "bad" rpm, or accelerate very gently through it? Does it cruise stably at 4000rpm, or does it muck about even then?

scottydouk

iTrader: (3)

Is car completely standard (engine side of things)?

smeddle

Good point, im gonna go a quick run now to have a look, if i left it for a bit do you think it could get worse? will post my results in a bit

Splitpin

Need answers to the questions posed in my first post too. If you're going to have a look under your bonnet, look for non-standard air filters/induction kits, decat exhaust pipes as well as anything attached to/around the turbo or boost control pack (which is bolted to the front of the offside front suspension turret).

While your're there also locate the mass airflow sensor (search on here if you're not sure where to find it) and check to see whether it has a stripe of green paint on its mounting flange.

Might also be worth lifting the front passenger carpet (and the metal cover plate) to check whether the ECU is the standard green label "Y7" MY00 part, or whether you have the pink label PPP ECU.

smeddle

Right, just took it out, yeah its only on hard acceleration, and i can hold it at 4k and its fine, and on slow acceleration theres no problem,

I know the cars completely standard, i looked around very thougherly and thought the history etc to find a standard one, its got standard air filter and cat etc, only thing is it has a big bore exhaust,

What you think?

Thanks for this help

(gonna go check the ecu, also sorry wheres the air flow?)

smeddle

Right, went to check the ecu, i know cars well and i know that the ecu covers never been taken off, didnt even bother to undo it because i could see that it definitely has never been touched, with the maf sensor, where abouts is it, sorry m8,

Thanks again for the help

Splitpin

And you say this happens in every gear, or is it worse in 4th/5th than the lower ones? BTW, try and avoid provoking this problem - i.e. drive in a manner that doesn't cause it until it's licked. Some of the things it could be have the potential to damage your engine.

Bear in mind some mods don't get listed - and some aren't immediately obvious to the naked eye, especially when, like you at the moment, the cars are new to you. There's one particular very cheap "mod" that some people try to get a bit more boost that can cause this sort of problem. Again tho it would help us to know whether the issue is the same in all the gears or whether it's worse in the taller ones.

Also, has it got a boost gauge fitted?

Like I said earlier, a quick click of the search button would have found you something like this:



Look at the pipe emerging from the air filter box and you'll see something like this. As above you're looking for a green stripe of paint (and the white printed text) on the sensor mounting flange.

If you don't see the paint/text, let us know.

Splitpin

Oh - missed your post above as I was writing. You're more than likely to be right about the ECU cover having never been removed, but seeing as you've already pulled the carpet and it's only three bolts and a nut you have to remove to check, can you take the cover off just to double-check for the green label "Y7" unit.

It might seem academic and unnecessary, but the more we can pin down about your car, the easier it is to help you rule in/out some potential explanations for this.

dabow

iTrader: (19)

could be the frantic weather, or just a simple maf clean really.
also the plug spacing ect

smeddle

The sensor has no green paint or writing, what does that mean??

smeddle

?? lol am worried now!

smeddle

Also just checked the ecu, yeah its green standerd, says y7 on it, really dont think its ever been touched, was a mish to undo thos bolts haha

smeddle

am getting very worried now, is it a massive problem? if i leave it will it cause damage and what does it mean that the sensor has no paint??
dont really want to take it in to be looked at unless i have to this month because sorta spent all my money this month on the car!

Thanks
Sam

dabow

iTrader: (19)

just see if the maf is clean mate, then the plugs.
if its a slight flat spot, could as i put aboth, be the weather
if theres no light, check the leads for breaks ect, also the condition off the plugs.

smeddle

how do i tell if the mafs dirty? soz am new to this, disconnect it? can i clean it myself, like wipe it?

Cheers

smeddle

also how does the weather affect it, lol sorry probs a stupid question, is it the temp that might effect it or what?

dabow

iTrader: (19)

yes it can mate, regards the maf. you can spray injection cleaner down it, as this can give a wrong reading making the car think its warmer air thus making it jolt

the other thing id check is the condition of the plugs, are they worn to the exstent the spacing is slightly wider ect, came across this lots of times.
it down sound to be really drastic, if its doing it when boosting up.
again, these are the simple things to check mate.

do you have an after market filter or standard air filter on the car

smeddle

standerd filter m8 as far as i know, thing is its due a service in a k, so think ill leave it until i get it serviced, probs in a month just so its done and il get them to check when thats being done i think, its not gonna damage the engine is it? it really is a slight hesitation, i got my dad to drive it and he says its barly noticble, just wanted to check, as im new to scoobies and this car i just wanted peace of mind tbh,

Thanks

sam

rhyshughes91

av got a impreza sport s reg. does any 1 know if the ignition coil is the same as the the wrx coil?x

Splitpin

The short answer is that it means you need to go buy a new one. The long answer is that if there's no paint, it means one of two things. Either you have a very old sensor (at least five years old, and the old design which is known to be prone to failure) or you have a non-genuine aftermarket replacement. Either way, as above, it would be a very good move to replace it with a new, genuine one immediately.

First thing you need to understand is, as I said before, there is no way for any of us to say with certainty what is going on under the bonnet of your car. The best we can do at this stage is use a bit of educated guesswork and experience based on what you have told us.

One of the common causes of the type of symptom you are reporting is a failing airflow meter (aka mass airflow sensor or MAF). Given what you've said, the first thing I would suggest you do is fit a new one. Firstly, because it may well be that this is the cause of your problem. Even if it isn't, driving around on a MAF sensor that is either very old (or aftermarket) is a bad idea. If you buy a new one and the hesitation remains, at least you know you have a new, reliable sensor in place and can move on to other potential explanations. Either way, as above, you can't rely on the accuracy of your current MAF and you'd be well advised to replace it. Your dad may think the hesitation is inconsequential - and he may be right. The problem is that he may well also be wrong, and right now it's better to be cautious than take an avoidable risk.

The bad news is that a new MAF unit is currently £105 here (and you'll also need some security Torx screwdrivers to change it). The good news is that this is going to be a good bit cheaper than buying one from a Subaru main dealer.

Without wishing to alarm you unduly, the worst case scenario resulting from driving around on a failing airflow meter is a blown engine. That's why, especially given what you've said about the lack of the green stripe, it's worth shelling out on a slightly speculative basis now.

If you do get one, perform an ECU reset (via the black and green plugs) immediately after fitting it and then see if there's any change in your symptom.

It is also, as Dabow suggests, worth checking the condition and gapping of the plugs, and further, open the airbox and physically checking whether or not it's got a standard Subaru filter in it (Subaru one, as far as I remember, has an orange foam surround and a yellowish folded paper element) or not. If it's an aftermarket one, let us know - especially if you can see anything that gives away what make it is.

You can't tell if it's "dirty" because you can't see the measuring cel (it is hidden underneath a cover and the only way to see it is to break the sensor open). In any case it doesn't/shouldn't get "dirty", because there's an air filter in front of it pulling all bar the tiniest particles out of the intake before it reaches the MAF. And despite what has been said above you can't "clean" it effectively. Most of the time, when these sensors start to fail, it's the result of fractures in the internal wiring caused by the effects of vibration, and no amount of "cleaning" is going to fix that. As above, given what you've said about the lack of green paint (and therefore what we know about its age), a new one is in order.

dabow

iTrader: (19)

i wouldnt say the maf has fully gone, and i wouldnt touch the sensor in anyway

if the maf is fully gone, it can course car stall. but if its dirty, it can course what your getting.
unless its fully gone, i wouldnt get a new one. again cleaning the unit may improve things.
again, also checkthe plugs for the spacing 0.7mm

there was some models with a flat spot. sure it was the 99

Splitpin

Dabow, I know you're trying to be helpful but did you read my post properly before contributing? I wouldn't say that the maf has "fully" gone either - it clearly hasn't, because if it had, Smeddle would be telling us about a check engine light and code 23 on the black plugs.

There is, however, a significant risk that it has partially gone, especially given that it is at least five years old and is the old type sensor. Unless the OP has some datalogging kit (and is thus able to examine the sensor's output in real time), the safest way forward under these circumstances is a precautionary replacement for a green stripe unit.

Don't know quite what you're trying to say there but as that sentence reads, it's wrong. If the MAF is fully gone, the check engine light will come on and the car will actually behave itself quite well, albeit in limp mode. If it is damaged/partially gone, stalling is one of the possible symptoms. However, they don't all fail that way. Some go in a manner where they work fine at idle, but under-read or drop-out like a t*t under load. The latter type are the engine killers because they actually make it feel faster at first, due to the leaner mixture.

Again, I'm not sure where you're getting your info but there is no reason why a properly sorted 99-00 UK car should cough under acceleration in the manner Smeddle's is doing. You are perfectly correct to suggest plug condition/gapping as one possible cause of this problem. However, that doesn't change the fact that a new airflow meter is money well spent, whether it's contributing to this particular problem or not.

smeddle

Thanks loads guys for all your help, i have booked the car in for a service this friday and will tell the dealer (a proper subaru independan garage who i know r good, hopeflly not to expensive) all about the problem, its the only time im gonna drive it this week to the place becasue i really dont want to risk it, i really tried very hard to find a clean 00 impreza, and it really is, but i dont think the maf has ever been repleced, fsh, cambelt done at 45k,no mods, 69k miles, hpi clear etc, i did look through the hitory the other night and cant find any mention of a new maf, it is due a servcie so with those to hoepfully it will be fine,
With a ecu reset, which they will obv do if they fit a new snesor, can i still drive it fast? i never ever redline it but i do like to go to 5-6k and iv heard with a reset the engine likes to adapt and learn your driving style, make sense?

Thanks loads again, will keep u updated
Sam

dabow

iTrader: (19)

ive come across 2 scoobs i did, where the light never came on. but kept stalling, changing the maf did sort this out. regards flat spots, it was off here
scoobynet some time ago. and yes, under stand what your saying mate. every car can have differnt problems, but be the same part damaged

but like every post put up, you can only go on whats been put.
every thing posted is only advice, not deffenatly the exact fix.
ive personally had my fair share of scoob issues over the year.
and managed to sort them out via scoobynet

Alpcar

First thread for me!!! I'm looking for advice on the same syptom I think..I am in a similar boat..I have bought a mint, fully un-modified, fsh,02 Forester XT a couple of weeks ago.
I drove to Germany and then Switzerland last week on holiday..The car is running great, when warmed up ticks over at 750rpm, and pulls great through the gears. But I noticed when in 4th a couple of times, when I gave it loads of pedal when joining a new autobahn, it hiccuped slightly around 4000rpm, then carried on fine. Now when I tried it again a few times but gradually with the pedal,it was fine.
I have noticed when it is just getting warmed up while driving urban conditions normally, and I clutch and change down the revs drop, then suddenly they race a bit up and down and then settle to normal. It happens when using the clutch really when I take the load off the engine when changing down. Could this be the MAF sensor??
I have just had an oil change at a mechanic here in Germany and I wanted the plugs changing, thinking maybe its the problem, but he said he couldnt do ot as he hasnt got the special tool...Is that true you need one..? I know there isnt much room.
ANy advice would be great, top forum...

Alpcar

Also forgot to mention that the OBD light came on at times for a few hours at a time while on the autobahn, then went off..It was never flashing and the car was driving ok, getting that read on Monday as garage forgot to do it today...cheers..

Splitpin

You're most probably right re. the MAF. Hence the prerogative to fit a new one now. The current sensors are made to a modified design that makes them more resilient. The old ones, as you'll see on here, have a "reputation".

You can reset the ECU yourself easily - don't assume that they'll do it, ask them whether they have and do it yourself if not.

Your question makes sense but the car doesn't work in quite the way you think. Yes, the ECU is capable of learning certain elements of its behaviour according to the quality of fuel you put in and the way you drive, but these adaptations are pretty limited. You can carry on driving exactly as you normally would after a reset - all the learned corrections will be re-learned (and are constantly updated and refined) as you drive anyway.

Yes, I'm well aware of that, have seen similar myself. The key point is that those sensors were partially not completely failed. There's a stack of stuff in my posting history about stuff like this.

Wouldn't be the first time someone's written something here that doesn't turn out to be correct. Bottom line is that the advice you gave earlier up in the thread - in particular about leaving the old mass airflow in place, is more likely to be unhelpful than the reverse. Again, I know that isn't what you would have intended, but it is what it is.

Splitpin

Welcome, although for future reference, it's usually easier to start your own thread (and if necessary link to another you believe may be relevant) than to drop onto a pre-existing one. Anyway...

Could be, but there are a bunch of other possible explanations. Ironically old or wrongly gapped spark plugs, as per earlier up the thread, are another common cause for this sort of thing. To whit...

No, total b*ll*cks. There is a special telescopic wrench available but you can do the job perfectly capably with a regular plug socket plus wobble extension/universal joint/whatever.

IIRC the Forester underbonnet layout is virtually identical to the Impreza. In which case there's more than enough, especially if you remove the airbox and screenwash tank. Your mechanic is a dweeb.

What was the result of that then?