not12listen

This might be exactly related, but it might be useful.

My wife's 1999 Outback was having misfiring issues randomly. I replaced the fuel filter, as we had no idea when it was last replaced, and since that time (nearly a month ago) there have been zero misfires.

This is after I had replaced the air filter, IACV, spark plugs, plug wires & ignition coil.

But you replaced both sensors and both OCVs at the same time, right?

 

So it's not clear what the actual root cause was, correct?

That is correct.

If I had to venture a guess, it would be the AVCS's. Those actually move, whereas the cam position sensors do not, meaning (to me) they are more likely to fail.

I replaced all 4 devices as I don't have time to worry about only replacing the AVCS's and then the issue returns (ie. if the cam position sensors really were the point of failure), as this is my daily driver and how I get kiddo around.

The downtime is far more negatively impacting VS the money spent.

Yes, I was getting the P0340.

The task is complete. I was able to replace both AVCS devices and both cam position sensors. It was not the most difficult task, but it was mildly annoying. A healthy dose of dielectric grease was used on every electrical connector that I could get too.

While doing this one of the PCV hoses decide it hated being in 1 piece and decided to break into 3 pieces. YAY! New hose was installed and new worm gear clamps were gifted wherever possible.

The result? Starts and idles perfectly. Warm-up is normal. Driving at low speeds and low RPMs is normal.

And then we get to the dreaded highway... Not only was the power delivery smoother, but it was more consistent! I was doing a data log purely for the sake of it as well, just in case something went awry. It hit 15psi - stock turbo, Cobb 3-port boost control solenoid, and stock everything else (both cats, 100% of the exhaust, etc).

I have to say, this is absolutely the best it has ever felt! It has to be noted that this was only a 3 mile drive in total. I'll be monitoring it and report back at the end of this week if anything changes.

Word to the wise: If you're going to replace the AVCS devices, it wouldn't hurt to replace the cam position sensors at the same time.

I had to pull the battery out (easier access), so the ECU was reset.

Hey, just wanted to reach to see if you had any luck fixing your issue. Also, just to confirm....the code you get is P0340, right?

 

Thanks,

$$$

The final parts are set to arrive today, and I'll be installing everything this weekend.

I'll report back the results after a few days.

Of note, something that helped to reduce the misfires, was to replace the fuel pressure regulator. There is no hard & fast rule per when to replace them. Once you notice your fuel economy starts dropping noticeably.

https://mechanicbase.com/engine/fuel-pressure-regulator-symptoms/

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Just as an update: all the parts are in my hands.

https://www.subarupartsdeal.com/parts/subaru-valve-assembly-oil-control~10921aa080.html

That is the AVCS for my 2006 WRX. Of note, when I called the local Subaru dealership, they could not get near that price - as in, they quoted $184 per, and would only offer a 10% discount. The next local Subaru dealership priced them at $135 per.

Needless to say, if you are going to order them, the 'cost' price is around $92-$94 each. Just keep in mind that shipping times will likely be longer than what is stated, so order accordingly.

I would also try cleaning the oil control valve (OCV). That controls the cam shaft timing advance and can go bad. I had a hell of time with my outback XT and once I replaced both driver and passenger OCV and both cam shaft sensors all misfire codes went away. I only used used OEM parts as well. I hope this helps.

Thanks for sharing that tid bit of info. I hope that we don't have to go to that point as well - the money drop on parts gets rather tiring.

I am curious why this is the first that I've heard about that part in specific being a possible solution (maybe I haven't searched enough?).

10921AA080 - Valve Assembly Oil Contro

That is the OEM part number and name that I've been able to find.

https://www.subarupartsdeal.com/

Has a very nice price compared to direct from the dealership, but there are others that have virtually identical prices too, so shop around.

I just found this thread today, as I'm getting the same CEL code on my 2006 WRX.

I've already replaced the factory fuel pressure regulator with another OEM fuel pressure regulator unit. The CEL still comes back randomly.

I already have both cam position sensors on the way in. But, I'm going to try something that I've done for every other car that I've owned - I'm going to apply dielectric grease to every plug that I touch.

I've already been told that it prohibits electrical conductivity, which is true, but it also pushes out of the way easily allowing physical connections to occur without issue. It would act as a barrier to the ingress of moisture - this helps to limit corrosion on connectors over time.

I'll give that a shot this week and report back my results.

Oh, other than a Cobb AP Stage 1 tune, my WRX is stock. I have upgraded parts like the head gaskets & head studs, a Walbro 255lph fuel pump (5 years on it). But, still on the stock turbo, stock boost, etc.

I am looking to either swap in a 2000+ Legacy Outback HVAC (for the cabin air filters) into a 1999 and earlier model OR looking to see if any air filter would fit in the existing 1999 location.

Do anyone have a spare blower setup and housing that I can borrow? I'll take measurements, send back the original and share all of my findings.

Thanks!