Legacy Non-Turbo missing when cold...

Legacy Non-Turbo missing when cold...

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The Boy Lard

Original Poster:

462 posts

230 months

Wednesday 18th April 2012
quotequote all
Hello,

I've recently bought a Legacy 2.0 non-turbo. It's a 2004 Jap Import (imported to NZ).

Anyway, when it's cold it's sort of mis-firing - not being an expert we took it back to the dealer and got the plugs changed, but it's still doing it. So we took it to the Scooby dealership and they suggested it's one of three things;
- Knock Sensor
- O2 Sensor
- one other sensor

Cheapest of which was $175 and the most expensive was $800

So just wondering if any of you had similar experience and which one of the three you'd recommend replacing?

Thanks guys...

Vixpy1

42,674 posts

271 months

Wednesday 18th April 2012
quotequote all
Coil Pack maybe

ScoobieWRX

4,863 posts

233 months

Wednesday 18th April 2012
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Can you get hold of an OBDII code reader. Just make sure you haven't got any errors coming up and you can see what it's doing while it's running cold.

Before you go spending money on sensors that may or may not be faulty clean the MAF sensor and the Idle Air Control Valve out. A dodgy battery could also cause you an issue, specially when cold.

ETA: Get yourself a VAGcom cable off eBay and a copy of FreeSSM of the internet for full Subaru Diagnostics on your laptop, if you have one.

Additionally have a chat with GravelBen. He is a Legacy owner and knows his way around them, and lives in NZ.




Edited by ScoobieWRX on Wednesday 18th April 16:53

The Boy Lard

Original Poster:

462 posts

230 months

Friday 20th April 2012
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Thank you ScoobyWRX, I'll look into it and let you know how I get on.

GravelBen

15,912 posts

237 months

Friday 20th April 2012
quotequote all
+1 to giving MAF a clean if its running rough, Vixpy's coil pack suggestion sounds reasonable too especially if its a clear miss rather than just roughness. Sometimes something as simple as a bad earth can drop voltages a bit to cause that sort of thing too.

Worth asking on clubsub.org.nz too, might find someone local with an OBDII reader you can borrow to check for error codes.

Edited by GravelBen on Friday 20th April 12:47

JollyGrnMonster

887 posts

204 months

Friday 20th April 2012
quotequote all
Sounds coilpack or spark related to me too.

The fuel mix is denser when the engine is cold as obviously it is richer for cold engine and as the engine warms up it lean out and the spark jumps the plug gap easier rather than routing to ground elsewhere.
I presume its on four coilpacks?
Should get a secondhand ones easily enough.