Hi,

I'm getting a piston misfire code on my 2001 WRX. My local mechanic tells me it's only two of the four pistons. The car drives fine.

It's booked in for it's first service since I've owned it (just over a week) on tuesday so I thought I'd call the dealer to get an idea of how much it'd cost to replace a couple of pistons if they deemed it necessary.

They estimated £600 for labour alone. That seems like a lot to me so I thought I'd check what advice Scoobynet has.

 

I assume this was a private purchase?

 

I would have thought a miss fire would be pointing to the leads,plugs coil pack?? Replacing a couple of pistons isn't the norm, and would think it would be nearly as much as a full rebuild with the labour involved. Get it taken to someone who know's what they are talking about mate.

 

Thanks for the prompt reply. This is what I was thinking - given that the fault is intermittent and doesn't affect the way it drives I'd have thought a piston pack would do the job. So I was sceptical when the dealer said it'd need new pistons. I'd like to think the dealer would know his stuff.

I'm awaiting a price from my local mechanic so we'll see.

Thanks again for the advice

 

get it to a specialist who knows what there doing, end of.

 

99% of the time a duff piston would make the engine running like a bag of spanners.

 

Yeah, from a VW specialist who had it come in as part exchange. It was recently MOT'd and the service history was OK. It's had a new timing belt, breaks and full service under 3,000 miles ago so it looked OK for my first Scoob.

I'm pretty sure replacing pistons is excessive and a piston pack will do the job.

 

Phew, I doubt it's that then. It's only an amber warning light and it only comes on every now and again and only when I give it some welly. It drives just fine and I wouldn't know there was a problem if not for the amber warning light.

 

Right, that's my next task, posting in the Welsh section to see who's recommended.

 

hang on a mo, its miss firing when you boot it?

 

I've not had it long and I'm being pretty sensible in it so it's not had a real boot. The only time I've noticed the warning light is nipping out to overtake someone. It flashes then goes out most times. It might be coincidence that that's the only time I've noticed it as I'm keeping an eye on my speedometer!

 

Which makes it a trade purchase - the vw specialist must repair (or have it repaired) for you.

 

What's a "piston pack"? Your problem sounds like a coil to me.

 

That's interesting. It was via a classified on eBay. Make any difference?

 

any idea on what revs you were doing and if its still running the standard ecu?

as far as when the light comes on do you notice any performance change?

 

private sale means sold as seen, its buyers responsibility to check its all ok.

 

My local mechanic suggested a piston pack (around £180) - assume it's leads, plugs or the like - something more disposable involved in the pistons and not the pistons themselves. I'm no expert so might have got that wrong.

 

Definitely no performance change when the light comes on.

I haven't noticed the revs but I'll keep an eye on it for future reference.

Not sure if it's the standard ECU but I haven't been able to connect to it with my ODBII-to-USB lead, which I was assured would work on any Subaru.

 

Sounds like neither is your local mechanic

 

lol, is a "piston pack" utter voodoo?

 

When you said you got it off a VW specialist who took it in part ex, it suggested to me it was not a private sale. Do you have any receipt for the car.
How does the law stand when a trader sell a car privately?

 

a misfire you'd more than likley feel. It might be running an aftermarket ecu, so could be flashing up a nock/det warning, or it might actualy be smply a shift light.

You need to get it to a specialist mate, they will be able to look what has been done to the car and go from there.

You could chase the fault round the engine bay and still not sort it spend hundreds of pounds for no reason.

 

think he means coil pack...

 

Haven't got a clue - honestly.

Your best bet is to find local owners and ask who looks after their cars.

Has the car been modified?

 

Probably meant coil pack mate. I think your car has 2 coils that are more than likely together as one unit. Each coil will operate 2 cylinders on a wasted spark cycle. Look at which cylinders the HT leads go to from each coil. My bet is you will find its the 2 cylinders operated by one of your coils that are not working properly.

 

Thanks for the advice - I've just posted in my regional section to do just that. I deliberately chose one with no mods, respectable service history and a long MOT.

 

Thanks for that, that makes a lot of sense. It's piston 3 and 4 I think.