Outback 3.0 misfire

[jr502]

Hi all,

I've got an intermittent misfire, which seems to be on random cylinders, codes p030X come up, usually 3 or 4 cylinders at a time. Last few times it has been cylinders 1-4. It happens, enough to trigger the CEL, then usually goes away after the next 3 journeys (expected time to clear CEL).

The car drives fine, it seems the condition which can trigger this is when you're very lightly touching the throttle, like it's not sure to idle or give it gas.

I've changed plugs, air filter, cleaned MAF and cleaned PCV, and it's still doing it. The car drives and runs fine, no other symptoms, it's just the new MOT rules around CELs being a fail, makes this a bit more urgent. I did think about changing all the coil packs, but then that's got me thinking about diminishing returns on my £, given the age. Although I don't like that train of thought as it's a lovely car and still drives nice. I would have though coil packs would be consistent cylinders.

This is a 2006 3.0R.

Thanks in advance for any help.

[loskie]

what about plug leads?

[jr502]

I can't seem to find plug leads on the normal online parts suppliers. I'll have a dig around. Thanks

[markiii]

If it has coilpacks it won't have conventional plug leads

[jr502]

Ok, that explains only finding coil packs and plugs in the normal sites. thanks.

[Konan]

Can you feel the misfire at all or is it just codes?

[loskie]

no plug leads I didnt know that, thanks.
Every day a schoolday and all that.

[jr502]

Konan said:

Can you feel the misfire at all or is it just codes?

No, not really. Have felt it very occasionally when just touching the throttle, but it feels like a single minor blip. But almost always I can't feel it and it appears to be just codes.

[Konan]

jr502 said:

Konan said:

Can you feel the misfire at all or is it just codes?

No, not really. Have felt it very occasionally when just touching the throttle, but it feels like a single minor blip. But almost always I can't feel it and it appears to be just codes.

There are a few input conditions that can cause the cars to throw misfire codes on multiple random cylinders when there's no misfire. Quite common on the Impreza to be the neutral position switch on the gearbox on the way out!

I'm guessing that you've got an auto on a 3.0 Outback (5 speed?) so maybe not that, but it's an example. How often does it happen? If it's not too infrequent, it may be worth getting the car logged.

[jr502]

Konan said:

There are a few input conditions that can cause the cars to throw misfire codes on multiple random cylinders when there's no misfire. Quite common on the Impreza to be the neutral position switch on the gearbox on the way out!

I'm guessing that you've got an auto on a 3.0 Outback (5 speed?) so maybe not that, but it's an example. How often does it happen? If it's not too infrequent, it may be worth getting the car logged.

Yeah, auto box. It's becoming more frequent.

[Bansheemax]

I've had a very similar issue, light throttle input at approx 50mph, would cause hesitation.
This the manifested into miss-fire on 3 cyls (2,4,6), MIL light and codes.
Turned out to be the LHS AVCS solenoid.

If you have access to live data from the engine ECU, via the likes of FreeSSM or Romraider check the operation of the AVCS solenoids.
They should operate cleanly together, within a few degrees, not erratic like mine did.

It's also worth checking the rough running monitor for all 6 cyls, if it starts to count, when very hot, the coil pack are on their way out.
When I mean hot, sat at idle for at least 45mins after a drive.

HTH

[jr502]

Bansheemax said:

I've had a very similar issue, light throttle input at approx 50mph, would cause hesitation.
This the manifested into miss-fire on 3 cyls (2,4,6), MIL light and codes.
Turned out to be the LHS AVCS solenoid.

If you have access to live data from the engine ECU, via the likes of FreeSSM or Romraider check the operation of the AVCS solenoids.
They should operate cleanly together, within a few degrees, not erratic like mine did.

It's also worth checking the rough running monitor for all 6 cyls, if it starts to count, when very hot, the coil pack are on their way out.
When I mean hot, sat at idle for at least 45mins after a drive.

HTH

Thanks for the help, I've been away hence the lack of reply. It's been in the garage this week, so just need to catch up on whats happened.

[jr502]

Bansheemax said:

I've had a very similar issue, light throttle input at approx 50mph, would cause hesitation.
This the manifested into miss-fire on 3 cyls (2,4,6), MIL light and codes.
Turned out to be the LHS AVCS solenoid.

If you have access to live data from the engine ECU, via the likes of FreeSSM or Romraider check the operation of the AVCS solenoids.
They should operate cleanly together, within a few degrees, not erratic like mine did.

It's also worth checking the rough running monitor for all 6 cyls, if it starts to count, when very hot, the coil pack are on their way out.
When I mean hot, sat at idle for at least 45mins after a drive.

HTH

I've just had a look with freeSSM, but it doesn't look like you can log the data, only view it live. I did notice that the the VVT on one side remained at 0 while the other side would go from 0 to 5.

It looks like Romraider allows logging of the data, so I will see if that's as easy to use,

[jr502]

OK, I've tried out Romraider. I did a short test logging the Intake VVT advance, and the left/right definitely do not match, so that seems odd. The duty cycles are below as well.

[jr502]

For anyone else getting this, I changed both the AVCS solenoids and it's now fine.

[Konan]

jr502 said:

For anyone else getting this, I changed both the AVCS solenoids and it's now fine.

Good news.

It's so so handy being able to read every single sensor on the car, isn't it?

[jr502]

Yeah, it really is. With the new MOT rules around engine lights, I was getting worried an unsolvable yet minor issue might be the end for the outback, but fortunately it lives on!