HELP! P0021 Intake Camshaft Position Timing - Over Advanced

[Scooby2.5]

Car is fixed. Mine was mostly a stumble stutter when first taking off. Didn't do it all the time and in the winter it was better, not perfect but better.

 

I finally got around to getting my ATR software going with my AP and monitored some ECU parameters.

 

Found the AVCS was ALL OVER THE PLACE.

 

I sometimes would get crazy numbers like 40 sitting still at an idle just reving up the motor a bit.

 

The two banks were not the same at times and my idle at times was terrible.

 

So today I put new plugs in, and the old ones looked real good.

 

But the real change was new OCV for the AVCS.

 

Once I put these in, my car is running great.

 

Those dang things affected my fuel trims B and C, had some knock once and a while, some roughness cylinder in each cylinder once in a while.

 

I found that when I had these problems (very intermittent) the AVCS was all whacked out.

 

Swapped OCV for the AVCS today and car is running great!!!

 

By the way car has 206K on it. I had changed these about 80-90K for poor idle and stalling and now at 206 they needed replaced again.

New Motor has 50K on it.

 

Here is a guy that says to change them at 70K as routine maintenance

 

http://epawd.forumotion.com/t96-oil-control-valves-on-avcs-dual-avcs-equipped-subarus

[Scooby2.5]

By the way I have used Rotella T6 and Mobile 1 oil filters at 3K-3500 OCI's

 

Banjo screens were perfect on my car but removed long ago on the passenger side.

[HAMMER DOWN]

I would not bother with the OCV, I do have both fiters removed from my 05 with the new ej257. Still have the orginal OCV's.

 

Same here:cool:

[Scooby2.5]

Well all I can say is you guys got lucky.

 

I think it is TERRIBLE advice to say not to bother with them.

 

Id say what you should do is log them and see what they are doing.

 

If the logging shows they are not responding to requested values, replace them.

[Scooby2.5]

Just my opinion but I would not bother replacing the OCVs for preventive maintenance; I would need to see a mechanical issue first. That's based on my understanding that a bad OCV in and of itself will not damage the engine (people more familiar than I with piston to valve clearance over the entire possible range of AVCS in these motors may wish to chime in here). Of course it may be a sign of impending doom depending on why it has failed. If it's the more serious banjo bolt/oil starvation related root cause, replacing the OCV itself as PM would not have staved off that failure. If a sticky/bad OCV is the root cause of the AVCS-associated CELs, you can pull it out and try cleaning it to free up the action, and if that doesn't work then the solenoid could just be bad and you can replace it then, and everything should be hunky dory.

 

Preventive maintenance that I would do to keep the OCVs and/or your turbo and the rest of the engine from failing prematurely would include running a quality oil filter with the right bypass spec, and removing the banjo bolt filters entirely because they were a stupid goddam idea in the first place.

 

If you saw what my car was doing when they were bad you would not say this

[Scooby2.5]

Maybe I'll just pull the OCV's and clean them when I pull the banjo bolts...

 

Just trying to be proactive (more commonly known as paranoid) as I get up there in miles.

 

Probably will not fix them. What happens is the Solenoid becomes slow to respond and then over responds.

 

You can try cleaning them, but probably will not do it.

 

Seems that when they fail its mostly problematic at low RPM. Driving down the road mine would seem to have the correct requested values from the ECM.

 

At any rate my car is fixed and logging found the problem

[HAMMER DOWN]

I do log them to see what they are doing. IMO change or clean when they are not running right. But if it's not broke don't mess with it. Around 220k when I did my last TB Service. There was 5* difference between right & left intake cams at start up. The two cams even up when motor got up to opt. temp. So before starting TBS, I ran Gunk motor flush thru it for 10min. After TBS & other maintenance. Both cams was back in sync at start up.

[Scooby2.5]

Yep that's what I would do.ine were sometimes 30 different:eek:

 

Sometimes hitting 40 just revving the throttle a tiny bit.

 

I've never had success cleaning them, seems solenoid gets slow but I could be wrong.

Pretty cool you have had yours that long.

[Th3Franz]

Replacing my OCV's tonight. One side has been reading 50* advance at idle. I should have planned to replace these from the start with my new build but didn't think of it. Good thread.

[Telephonewire]

Replacing my OCV's tonight. One side has been reading 50* advance at idle. I should have planned to replace these from the start with my new build but didn't think of it. Good thread.

 

Just had a similar scenario with mine - reading 51 advance (I think) at idle. It turned out to be a piece of swarf / metal stuck in the valve which I extracted with a screw driver - now works perfectly!

 

If the coil fails in the OCV then they tend to get stuck at 0 advance (which means they need replacing) but if stuck at anything over 0 advance the valve probably has something jamming it open.

 

If they are not jammed you can move the valve easily with a screwdriver against the spring and then when you remove the screwdriver it springs back to shut again.

 

Telephonewire.

[Th3Franz]

The culprit..

[dotsoncs]

Had the code (P0021) show up on my '05 XT Outback. I'm the only owner and performed all oil changes per the recommended (and updated) maintenance schedule. Given how relatively inexpensive they were and the success found by some, I replaced both OCVs. That seemed to help for ~400 miles but the code returned after a long road-trip.

 

I'm not confident enough in my own skill to pull the banjo filters but that might be the next step.

 

Question: Could someone explain how to read the Intake OCV and VVT data? Can your standard ODBII dongle + software do the trick?

[ehsnils]

First step - pull the banjo bolt and check the filter before you try some logging because it can make your turbo starve for oil - and that's going to be a major headache making your codes seem insignificant.

[Shotokan1509]

Now Im getting annoyed.

 

Similar situation as every other time, 2+ hours on highway below 20 degrees, short shutoff (gas station) and bam light again.

 

I had already removed the banjo filters, oil is high quality amsoil with filter only 1000 miles on it and full, I just replaced both OCV's about a year ago so 15,000 miles on them tops!

 

I cleared the code, ran without if for few hundred more miles and now popped up again. WTF

[Max Capacity]

Did you do a oil system flush ? Gunk Motor flush or Subaru motor flush will work.

 

I would do that. Let the engine run for 5-8 minutes with the flush in it, then change the oil. May be use a cheap oil and repeat in 500-1000 miles.

 

Did you remove both banjo filters ? Most people don't do the front one, which I believe is the bank 2 or the cause of the P0021. I could be wrong on that one.

[Shotokan1509]

Did you do a oil system flush ? Gunk Motor flush or Subaru motor flush will work.

 

I would do that. Let the engine run for 5-8 minutes with the flush in it, then change the oil. May be use a cheap oil and repeat in 500-1000 miles.

 

Did you remove both banjo filters ? Most people don't do the front one, which I believe is the bank 2 or the cause of the P0021. I could be wrong on that one.

 

 

I'm not a fan of flushes, afraid if theres buildup a bigger chunk will become dislodged and block a passage. I'll be doing another long drive to go skiing tonight, keep fingers crossed it doesnt pop-up again, if it does I'll atleast pull the OCV (or cross swap them) and do an oil change ahead of schedule to check it.

[Max Capacity]

Skiing, where ? I'm headed back to Okemo friday night.

[Shotokan1509]

Skiing, where ? I'm headed back to Okemo friday night.

 

 

Mount Snow for Fri & Sat.. maaaybe Sunday morning

[instantfury]

Add me to the list. p0021. 233k I recall doing the passenger side quite a while ago, but i am not certain that i did the drivers side. Hopefully it's just dirty.

[argyle409]

p0301 p0302 p0303 p0304 pfffe & w/e code is for fuel bank too lean

The intercooler was cracked so I had it replaced an the codes went away for

about 500 miles.

 

 

Then I got p0303 + pfffe… I had the compression test done all cylinders are fine, valves flushed of excessive carbon build up, along with spark plugs replaced, and then we looked into the IACV.

 

 

My car idles rough, and even stalls sometimes at lights, or like just 2 weeks ago backing into the snow/ice covered uphill spot the car completely stalled. My mechanic said only thing that looks off is the Throttle Motor Duty Cycle which he said he'd never had to work on such an issue. It was displaying barely 1 to -27%.

 

 

Cleaned out the IACV mechanic said to drive it around till today an see it the CEL goes away. It didn't so he had me reset it with the Cobb AP, car was running fine except for small hesitations in idle but nothing as bad as before. I then stopped to get gas, an when I turned it back on I got p0021 code pop up.

 

 

A friend suggested that all this headache is from the lightweight pulley?, it was on for about 2k before I had any code come up, other than the car taking a bit longer to catch an start up when I put the key in the ignition.

 

 

I have video of the car in idle, it starts in cold at about 1200 rpm, but once you put it in gear drops to about 900 an slowly makes it down to 650-700 (according to my cobb, however looks lower in person on tac). Once warmed up in park or gear the idle is no higher than 750rpm, just putting around the parking lot the car stalled a few times parking in spots. Only got it on video once, as it's hard to video while driving…

 

It's been 2 months diagnosing this problem, still no light at the end of tunnel…

[sleepysgt]

I got a got a couple of codes that have came up and I'm hoping someone can steer me into the right direction on how to go about fixing my car. I am a first time Subaru owner and lack knowledge towards these cars. P0021 P0171 . I have read a few threads already and couldn't find anything useful. Other than the codes I haven't really noticed any thing strange.

[Spec-Ben]

Hi everyone, just stepping in to see if i'm on the right track.

 

I had P0021 a couple week ago on a LegacyGT Spec-B 2008 I bought. Since it appeared, banjo bolt filters and OCV sensor has been cleaned, an engine flush has been done and timing belt changed. No trace of P0021 since then. BUT, since the beginning, there is a couple of really noticeable hesitation/miss between 3000 and 5000rpm at WOT and it is not gone. Can a faulty OCVS cause this kind of behavior?

 

I did a log, and to me right bank seems a bit weird vs the left one. Can anyone confirm?

 

http://i.imgur.com/USinCKf.jpg

 

Thanks in advance!!

[Max Capacity]

I beleive a OCV can cause that.

 

I would talk with a Tuner, I use Mike Kinsman at www.tuningalliance.com and have him look at your log. Tell him the background and see what he say's. You can tell him I sent you.

 

Also this thread get's lost over time. The 4th Gen forum or Powertrain forum is viewed more.

[gimpydingo]

Old thread, I know. Anyone replace their OCV on an 07+? It's a bit cramped in there. UGH.

 

 

EDIT: Oil fill tube has to come off, that was fun, for the drivers side OCV. Passenger seems the same as the 05/06.

 

EDIT: Got it all done. Cleaned them with WD40, got as much of the gunk out of the solenoid as possible and swapped sides just for the hell of it. Still low idle. Car feels good though.

[Catalyst]

What should these look like while inspecting them? Can you tell visually if they should be replaced? Would hate to blow almost $200 if they dont need replacing..