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Misfire and fault code woes....


Hughieboy
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Evening All..

So I just bought a 2006 2.5xt and some of you may have seen my earlier post that the day after I bought it the engine light came on, I took it into my local mechanic and after diagnostics and a phone call to Subaru (he's not overly familiar with Subaru's particularities) the secondary air valves were diagnosed as knackered and needing replaced. The car also had an intermittent stutter/misfire that wasn't apparent on the test drive but became noticeable on the drive home.

So the parts took two weeks to arrive, has duly been fixed and 5 miles and £783.00 after collecting it the engine light is back on..... and although not as bad, the stutter/misfire is also still present.....!

I really don't know what to do. The mechanic, who is a good and genuine bloke who I've been using for years on other cars didn't seem over confident when the car was collected. He said it looked like someone had 'had a bit of a go' at 'fixing' the valves before and there was a split pipe and bolts in the wrong place etc. He just wasn't that happy and now nor am I! He said if I had any more problems we might need to replace the secondary air pump as it didn't seem to be doing much but that if that happened he would be concerned at how much money it was all going to cost and I should look for a used one. Regarding the misfire, I had read about problems with coil packs but he said that they and the plugs aren't due to be replaced for another 20,000 miles and as they are expensive and awkward to get to he left them as they were.

So...... Is it likely that the air pump would throw up another code if it's playing up? And is it likely to have anything to do with the misfiring (I don't understand that bit, I thought it was all to do with emissions....)?

I'm going to have to go back and speak to him as I've spent so much money already but I don't want to start spending shed loads on guesswork. Should I cut my losses and take it to a Subaru specialist? I've just found out there's a place called ED Motorsport near me who work on Subarus amongst other things.

Can anyone with a bit of knowledge and experience of these cars advise on what might be the best course of action?

I'm sorry for the long post but I bought this car with full service history for £2800 and have done less than 500 miles in it so I'm feeling a bit lost for what to do for the best.

Hope this all makes sense, I just need it to work as it should.

Thanks,

Hugh.

 

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Best bet would of been removal of the secondary air system, system is just a con to dilute emission readings and best place for it is in a metal skip.

What is current code for CEL

Ideally you going want pull plugs and check them and the coils, as they hard to get to they get left a LOT, I've done a few even ones with stamped recent  history have had junk plugs that been overlooked out of laziness. I would get them pulled inspected and bang a new set in just to eliminate basics plus plugs sorted for long term .

Big mistake so far was spending on air valves, about half that cost would of had it removed from map and blanked thus never anymore issue.  Hopefully current cel more related to misfire ! Going Subaru specialist is way go as generally we can pinpoint areas of fault more accurately and wisely invest your money for long term benefit . Good luck .

 

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Thanks again Mr B....

I spoke to my mechanic again earlier and it's a shame I (or he) didn't realise this earlier about the secondary air delete option..... it was a local Subaru main dealer who he went to with the codes that advised changing them and supplied the !Removed! things! By the time I discovered the delete option via being on here etc the parts had been ordered and had to be paid for. However, to be fair to him, that cost included a service but plugs weren't supposed to be needed on this one. I think he's pretty !Removed! off about it as the valves themselves were something like £220 plus VAT each so I guess he's been as reasonable as he can, I know he wouldn't want to overcharge me.

However, when I spoke to him earlier, he also said he wondered if the last plug change had been 'overlooked' as it's such a ****** of a job so he's going to have it in in the New Year and change them and check the coil packs. I asked him if he would rather I took it to a Subaru specialist but he said he'd like to have another go at it first so I think he'll look after me on it. I don't know what the fault code it's throwing up now is as I can't check it and I don't have time to take it in again this side of Xmas.

So, on one hand I feel like I've bought a bit of a pup but in its favour the car is in really good condition inside and out and as long as it doesn't cost too much more to get it right I will still be happy. I've looked at ones in worse condition cosmetically than mine that were up for nearly a grand more than I paid.

So I think he's now thinking what you're saying. Thanks for your advice and we'll see what happens when the plugs are changed.

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Just watched a YouTube video on it.... see what you mean, not horrendous but definitely a faff.....

I think I'll put up with it for a couple of weeks and let the garage do it, they can check the coil packs as well, I wouldn't know what I was doing with those...

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I would advise you get a cheap obd reader. Either Bluetooth dongle for torque app if android user or simple stand alone handheld unit (£10) worth their weight in gold and just store in glove box . Is an eBay link to one in couple threads.

Your buying price seems fair and if condition super clean it still worth it. Problem with air valve system is you likely end up buying most parts get it fully working so is expensive . Misfire hopefully easy one (if indeed misfire). Coil packs split so likely cause along with plugs and a must 1st check area, boosted cars need A1 ignition system, higher compression from boost equals more resistance so systems fails easier. I would assume previous owner sold due to air valve issue, main dealers would priced that at heart attack figures. You best avoiding main dealers as much as possible as besides basic servicing they got little older vehicle fault experience and only know replacing oem new for old .

Stick with it as likely get perfect with bit more time and money . Your mechanic sounds genuine and helpful, Subaru very easy work on once gain basic knowledge .

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Thanks for that, I appreciate it and it gives me confidence in the car.

The moneys done now on the secondary air issues and I'll put it down to experience and 'rabbit in the headlights' syndrome as I didn't know any of this at first. If the pump goes as well at any point I'll get a secondhand one, I just don't understand the justification for the sky high prices on parts that are known to be problematic..... Thanks Subaru!

However, after coming from a fairly new car which although it gave me no problems in 3 years also had monthly HP payments and no real character, the grin factor I get from this thing is immense! It's been a frustrating start but as you say, with a bit more time and money (hopefully not too much!) it should be a good 'un....... and without the monthly payments and depreciation of something newer to suffer.

I have taken your advice (funnily enough my mechanic suggested it as well yesterday) and bought a cheapy obd reader off Amazon, I hadn't even realised they were that readily available.

On a brighter note, I stuck a set of Pedders struts on the back last week as it's a*** was dragging in the weeds a bit and what a difference that has made! Totally transformed the ride height and handling and worth every penny.

We like a bit of a project I guess, keeps things interesting..... ;-)

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In long run it will probably be cheap fun car .
A scruffy body is worse than small mechanical niggles, you never get same paint quality as the older factory original paint, they can last well over 25yrs with basic care. It quite hard find unmarked forester SG's as bumpers and arches so easily marked as all painted and over prominent .

Hopefully you new valves have the air system working okay so you won't be back tracking on that and to be fair they should last your ownership hopefully . Old Fozzies look like sick dogs with the saggy butt, handling is indeed awful when sls strut hydraulics fail. Subaru parts prices are shocking, new rear shocks would cost about £800 a pair for bare shock strut :-O they would be wise discounting prices on common older parts to keep the business and subaru dealer image but they not too smart so it falls to us subaru specialists :-)

Be fussy with your servicing (quality ester synthetic for engine changed regular and good coolant, 2,5 head gasket issues amplified from poor oil and old or bad choice of antifreeze), use good fuel and motoring should be pretty smooth going with luck . Crack on and enjoy it, wiser spending on this than having newer junk on credit .

This is link to cheap easy use code reader, work well on subaru and what I recommend to users who not into obd via phone app .
http://www.ebay.co.uk/itm/Car-Engine-Fault-Code-Reader-Diagnostic-Scanner-Reset-Tool-OBD-2-CAN-BUS-EOBD-UK-/172200936611

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Thanks Mr B, I'll follow your advice

I plugged my new OBD toy in this afternoon and the fault code was P0410 which I Googled and it said secondary air fault...... Aaagh! I deleted it and it didn't come back again today but maybe that's because the car was warm. And the misfiring is getting on my nerves.

Soooo...... I'll see what it does tomorrow but I don't understand why I'm getting that code as that is supposed to be fixed! And the mechanic can't look at it again until the New Year and we're supposed to be going up to North Wales in it for a few days after Xmas..... so I'm debating getting some plugs and coil packs an fitting them myself, I think the spluttering and misfiring might get on my t*ts on a long journey (although the Wife thinks I'm making too big a deal of it).

I'm ok with tinkering (mostly on old scooters and bikes though, not high tech Japanese cars!) so if it's an 'on the drive' job I might have a go...... is there any reason I shouldn't do you think?

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mmm possibly airpump, when valves been stuck open airpump gets rough time. see if code thrown again :-/

Plugs are a driveway job, how easy it turns out depends on what plug tools you have at your disposal, watch a youtube video and have a go, you may need invest £10-£20 in plug tools. It not hard just little awkward till got tool & technique sussed. Set of iridium plugs can be had under £35. Mark position of removed plugs as tip colours will tell you a lot about how cylinders are running. You will be removing plug coil packs off of each plug so best physically look at these, the plastic housing has a habit of cracking so have a good look at them for cracks and signs of arcing from a short, new decent quality set of coil packs around £160 so no point buying until had a look at current ones, plugs are cheap & might as well have new on hand and bang them in.

Under what scenario does it misfire, is it always under load/boost,does it ever miss when idling or light throttle ?

 

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I have plenty of tools and a couple of different sized plug sockets/extensions etc, I'll have a look at YouTube. I found a video or two on there but haven't watched them properly yet, some American fella has two showing replacing both sides.

The missing doesn't happen when ticking over but will be intermittent when cruising at low and higher revs and sometimes it will feel like it's going to stall momentarily if you put your foot down suddenly, it kind of stutters and then picks up. Nearly came unstuck the other day trying to sneak on to a roundabout, saw a gap, right foot down and ...... well, it was a hairy moment as it nearly stopped when it was supposed to go!

Regarding the coil packs, without wanting to waste money I just thought that if I was going to go to the bother of taking them all out I may as well just fit all new so that it's done as I can't test them. I'd rather do it once if possible and then I know they're all good, is that not a good idea? The labour element isn't going to cost me anything.... plus I really only have Friday afternoon/Saturday morning to sort it out  before we go away, I'm working all week then it's Xmas.. was hoping to cover all bases...

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Coil packs easy/quick remove compared plugs so no bother removing again. Up to you if want invest in set of new coil packs, will be £160 roughly and if issue not ignition then money wasted. I would ideally look at them and do road test with diagnostics logging . Plugs make sense as never a bad thing have known new plugs in, whether you go for coils is entirely your decision, I would try look at them asap as only 1 bolt & plug loom then pull off, if see crack or spark tracking marks then get new and fit when do plugs . Plenty other things could be causing hesitation/missing but I can understand the frustration .

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Thanks again Mr B, I really appreciate all your help with this...I'm going to go out this morning and see if the code comes back up when the engines cold first, I guess that will tell me whether the pumps knackered? Mechanic did say he was unsure how well it was working. I've looked at the YouTube videos so I will then assess the coil pack/plug change. So do you think I should pick up some plugs today and change them, inspect the coil packs while I'm at it an then if I see an obviously damaged one buy a replacement? Or maybe it could just be plugs? I guess that would make senses, a bit more leg work maybe but no point buying things I don't need and it will be quicker stripping out the second time having done it once. I expect I can get plugs from Halfords on a Sunday...

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Sounds a plan, if lucky it plugs, coil packs are reasonably common and finding a visually cracked one or more would in some ways be good :-)
If all coils look fine you would be wise do plugs and test outcome . expect Halfords or small car accessory parts store doing sunday trading can do plugs, prices won't be as good as online pricing wise . ngk or bosch plugs would do you .
Would be wise review you plug tools before going shopping as find may need longer tool/extension you can try source all in one trip.
 

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I'll see if i can do that if Halfords have the plugs..... Just one more question.... If I change the plugs and don't see any visible tell tale signs of failure on any of the coil packs, do I order a set and change them all at that point? Or is there a way of testing them off the car? And what would be the ideal socket/extension set up for doing this? Think I have most of it covered but I'll check before going in to town. Cheers!

 

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Update..... have removed the coil packs and can't see any obvious signs of anything untoward.... they're a bit old an dirty looking but no breakages, splits, corrosion or otherwise... the wires, terminals and plugs all look ok visually. Halfords don't stock the plugs so I've removed and then partly re-inserted one just so I don't leave the hole open to check I have the right tools, I'll need to get some online or something.

I'm wondering if there's any way I can test the coil packs while they're off? Is it likely/possible it could be a faulty plug? They should have been changed at 75,000 and it has now done 94,000, the book is stamped for the service but I guess that doesn't mean anything necessarily. I suppose it's a case of just change the plugs and see or change both and hope for the best? 

Do the coil packs have a lifespan whereby they would need changing anyway? I'm assuming the ones I have are the originals, they look pretty old.....

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Update..... I have replaced the plugs and also the coil packs with ones from Surefire..... they came next day! Anyway, it now seems to be running properly at last! I've just been for a 20 mile drive and all seems to be well, it's a different car! But what a complete pig of a job, no wonder the guy at the garage wasn't in a rush to do it! Especially the passenger side rear one, there was some colourful language in my garage last night I can tell you! Anyway, all's well that ends well and as an added bonus, for some reason there is no engine light anymore even though the code came up as being secondary air related..... maybe it's because I've reset the ecu by having the Battery removed for a couple of days? I have actually managed to buy a used but good pump of a guy on eBay for £60 but if the light doesn't come on I will put it on the shelf for a bit and see.....

Anyway, thanks again for all your advice, I am happy to have the thing running right at last.... for now at least!

Cheers :)

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Good result.

Those plugs get left a lot, I seen it even on cars with full dealer history and a recent last stamp :-/
Coil packs do play up a lot too, keep old ones in a zipped bag as not all bad so got spare or 2 .
Lucky really as DIY effort cost about same in parts as just labour/diagnostics probably and being done now means you get benefit of A1 new parts for the long run .
Plugs get easier with practise, just right socket and extensions make all the difference too.
Quite possible code not fully cleared or pump/valves needed bit of use to settle in .
Glad it worked out and hope all is well . Have a good run on your trip and enjoy the 2.5 ...

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Thanks...... there must be a proper technique for doing it. I can't imagine the Subaru dealer mechanics are messing about with different extensions and swearing and cursing and squashing their hands whilst doing it! Be interesting to know what the 'official' method is..... but I am glad it's done! 

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Another update.....

So, at first everything seemed 'cured' but it isn't unfortunately. Although the engine light has only come on once in the last few days (still showing code P0410 although I haven't changed the pump yet as I thought the issue had gone away) the misfire is rearing it's ugly head again.

It's not as bad as it was before and in fact isn't really like a misfire in the true sense any more, but more like a slight stutter. Not bad enough to make the car unusable but enough to be annoying as you find yourself looking for it and expecting it. It shows itself mostly when either, say, pulling away again after slowing for a bend at low speed. The car will jolt along a little, almost like you've let the clutch out too quickly or you're in too tall a gear if that makes sense. It's just lumpy. The other time it's most noticeable tends to be if you put your foot down to overtake for instance and it will hesitate a little. The rest of the time it shows itself occasionally by just missing a beat now and again.

So, I'm not sure now what it is. I think as it's running better it was worthwhile doing the plugs and coil packs as I know they are good now and whilst could have been symptomatic of the problem there are other issues. I guess I could liken it to driving a car with a manual choke if you've turned the choke off too soon if that makes sense. I've also noticed that when left on tick over the revs fluctuate from high to low quite frequently rather than being constant, I don't know if this is normal.

So I'm not sure what my next move should be. Could it be fuel related or the ECU? Should I get a leak down test done in case there's air getting in somewhere? Or could it be something else? It's all a bit of a head scratcher and I'm pretty surprised/shocked that a quality modern car with only 93000 on the clock should be this problematic, it's not like it's an old banger. I'm going to take it to Wales as planned and will need to address it in the New Year. Maybe it's time to visit a Subaru specialist.

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