club.liberty.asn.au

I have a 09 Legacy 3.0 A/T with about 70k Km's. Sometimes when I accelerate hard the RPM's will climb like normal then drop. Hold for about half a second then continue to pick back up. For example reach 5k rpms. Instant drop to 4k (You can feel the pause) then continue climbing normal till redline. It's not "surging" because it doesn't gradually go up and down. It drops to 4k like a stall then proceeds as normal. The rpms that this *begins at is not specific and it doesn't happen every time.

I have no check engine lights.
Fuel consumption is normal.
Idle is normal.
Car is completely stock and serviced by the book.
I pulled the AVCS solenoids and they look beautiful.

I'm thinking I am do for some plugs because I see no record of a change.
Could plugs cause this? With no codes for misfires etc?

Other than looks what can I do with the solenoids to check the operation? Ohms check?

What else am I missing that could cause that immediate drop in rpm with no other noticeable problems (lights, etc).

Going to clean and tighten battery terminals.

Does road speed increase albeit a bit slower at the drop point? If so, do an auto transmission fluid change Your getting a bit of slip in the trans, engine rpm increases faster than road speed and then after peak torque the transmission can catch up Basically like a slipping clutch in a manual, but grabbing as rpm increases which would slow engine rpm Vs road speed

As above...

Once fixed, get it tuned,
more power, more torque and better economy plus it won't ping it's head off and risk destroying bearings or ring-lands

Ok I read that over and over. When it happens to do it, everything slows down. If there is any increase in road speed its ONLY for the momentum I already have. It doesn't increase as if I'm still in the throttle. Its almost as if hitting a rev limiter. However there is no bounce like a limiter. It drops to 4k and then accelerates as if 4k is where I started...If that makes sense.

The trans slipping could very well be, but wouldn't this be a all the time thing? Or for example when I'm hitting high revs and the fluid is moving fast.....a contaminant could be blocking something for a split second?

The rpm in which it hits is never exactly the same but it always drops to 4000. Is 4000 rpms somewhere in the TCC for faults? As in if there is a fault revert to 4k, like a limp mode for the tranny?

I'm trying to understand what the car is actually doing that the trans would cause this.

I would give my left nut to get this tuned and was quite appreciative to see a tuner respond to this thread.
Problems with getting a tune:
1. Money
2. I have a tactrix v1 that doesn't support CANBUS
3. Money
4. I live in a country with VERY LITTLE support for any type of Subaru.
5. Money
6. KiDo_ doesn't come to my city.

For some reason it seems like my pm's aren't sending...hmm

EZLegacy wrote:For some reason it seems like my pm's aren't sending...hmm

Hi, PM's sit in the outbox until read. It confused me for a while as well.

That explains it. Thanks.

It sounds like that the knock sensor is picking something up and pulling timing.

Is there no way to get your hands on a newer tatrix? Someone that you can borrow from even?

It might be possible to get one...I'm hoping.

So you are saying that knock would give my rpm's a kick in the nuts like that? For example climbing past 5300 and BAM at 4000 for a split second and continue to climb back up? I understand any of the problems these cars could have can make it struggle to continue climbing or lag at a certain rpm, but to drop to that number...????

Also, considering the roads here are horrible could it be a false knock?
I specifically remember it doing in on the freeway....the few areas that have "better" asphalt. So that might be an answer to my own question.

Thanks

I tried to get a video....and well of course....it didn't do it

brainy wrote:It sounds like that the knock sensor is picking something up and pulling timing.

Is there no way to get your hands on a newer tatrix? Someone that you can borrow from even?

Vagcom can still log via RomRaider on CAN ECU's

as in the generic vw compatible ones from ebay? or an actual vagcom? I do still have the tactrix v1. I didn't know it would interact at all.

EZLegacy wrote:as in the generic vw compatible ones from ebay? or an actual vagcom? I do still have the tactrix v1. I didn't know it would interact at all.

Generic is capable of logging on RomRaider still. Just no flashing.

Ok so as I try to gather the things needed (money) to get some good logging done, like gas and a windows pc with a decent battery... I noticed something.


My battery is about to kick the bucket. It's some cheap looking garbage that was in it when I bought the car...but considering the Legacy isn't getting driven much right now it hasn't been getting charged up daily. The last few starts were rather slow and soon I know it's not going to start at all.

So my question is....will having poor voltage in the system be something that could cause this as well. i.e. the sensors aren't spitting back correct values/ or quick enough. At higher RPM's it just needs more juice to operate correctly?

EZLegacy wrote:Ok so as I try to gather the things needed (money) to get some good logging done, like gas and a windows pc with a decent battery... I noticed something.


My battery is about to kick the bucket. It's some cheap looking garbage that was in it when I bought the car...but considering the Legacy isn't getting driven much right now it hasn't been getting charged up daily. The last few starts were rather slow and soon I know it's not going to start at all.

So my question is....will having poor voltage in the system be something that could cause this as well. i.e. the sensors aren't spitting back correct values/ or quick enough. At higher RPM's it just needs more juice to operate correctly?

Once the car is started, it runs off alternator voltage anyway No influence.