Outback "bucking" in low gears

indy · Post by **indy** » Wed Jan 16, 2013 12:17 pm

Hey guys i have a really annoying intermittent problem (although, fairly frequent).
Its kinda hard to explain, but its mostly apparent in 1st and 2nd gear.
Usually very apparent when driving slowly through car parks and such, going over speed humps etc.
Has the feel of the car needing to be changed down a gear, but happens going downhill down my driveway in 1st gear.

The car will jump/lunge/buck, and continue to do so until i put the clutch in or gently tap the accelerator and this will usually correct it.
At first i just thought i needed to get used to the gearing of the car, as my previous car was an 88 L series and much lower geared. However, now I'm 99% sure it isn't that as it will happen downhill in first gear under no stress, and can become really apparent if i say go over a speed bump, after the car will keep bucking/lunging.

Couple of times i've just let it keep "bucking"/lunging and it just clears itself up. I haven't had it stall or anything from this.

Also, the car isn't very smooth on acceleration/deceleration. Will shudder/knock a bit on acceleration, and shudder/knock a few times when you take your foot off the gas on deceleration.

Mostly driving will be fine, the not so smooth acceleration/deceleration is always there, but the bucking in 1st and 2nd isn't always there.

----------------------------------------------
Since buying the car I've done:
Timing Belt + Idlers & Tensioners
Spark Plugs
Oil Filter + Oil
Fuel Filter
Cleaned PCV & IACV valve.
----------------------------------------------
It did seem better after IACV, although that being said its hard to tell as it doesn't always happen, anyway problem re-occurred after a couple of days of cleaning it.

When i took it for a test drive i didn't notice it, but did notice it a few days after driving around and just put it down to me needing to adjust to the gearing.

GEN3, 2001 outback Manual. 197,000kms

Thinking of changing plug leads next. Also when i changed spark plugs, there must have been oil in the wells as some came out when i pulled the plug leads out. Is this normal?

Davidov · Post by **Davidov** » Wed Jan 16, 2013 3:07 pm

indy wrote:Hey guys i have a really annoying intermittent problem (although, fairly frequent).
Its kinda hard to explain, but its mostly apparent in 1st and 2nd gear.
Usually very apparent when driving slowly through car parks and such, going over speed humps etc.
Has the feel of the car needing to be changed down a gear, but happens going downhill down my driveway in 1st gear.

The car will jump/lunge/buck, and continue to do so until i put the clutch in or gently tap the accelerator and this will usually correct it.
At first i just thought i needed to get used to the gearing of the car, as my previous car was an 88 L series and much lower geared. However, now I'm 99% sure it isn't that as it will happen downhill in first gear under no stress, and can become really apparent if i say go over a speed bump, after the car will keep bucking/lunging.

Couple of times i've just let it keep "bucking"/lunging and it just clears itself up. I haven't had it stall or anything from this.

Also, the car isn't very smooth on acceleration/deceleration. Will shudder/knock a bit on acceleration, and shudder/knock a few times when you take your foot off the gas on deceleration.

Mostly driving will be fine, the not so smooth acceleration/deceleration is always there, but the bucking in 1st and 2nd isn't always there.

----------------------------------------------
Since buying the car I've done:
Timing Belt + Idlers & Tensioners
Spark Plugs
Oil Filter + Oil
Fuel Filter
Cleaned PCV & IACV valve.
----------------------------------------------
It did seem better after IACV, although that being said its hard to tell as it doesn't always happen, anyway problem re-occurred after a couple of days of cleaning it.

When i took it for a test drive i didn't notice it, but did notice it a few days after driving around and just put it down to me needing to adjust to the gearing.

GEN3, 2001 outback Manual. 197,000kms

Thinking of changing plug leads next. Also when i changed spark plugs, there must have been oil in the wells as some came out when i pulled the plug leads out. Is this normal?

I got that in my gen 3 as well if i understand you correctly.
For example crawling around in a carpark, if i come off the accelerator the car will lurch/buck. Makes carpark driving quite uncomfortable. Never bothered to look into it but.

Post by **Alex** » Wed Jan 16, 2013 4:03 pm

could it be caused by a warped flywheel? Also other things that id look into are engine mounts, gearbox mounts and the engine stabiliser rod.

Changing the leads is worth a shot. Does it feel like an ignition or fuel problem(like a miss) or some kind of a mechanical bunny hop kind of motion?

The oil coming out when youre changing the plugs is from the cam cover seals. This is a common thing. My gen3 did it so i tightened up the bolts on the cam covers abit more which has fixed it for the time being. A proper fix would obviosuly be replacing the seals.

hope this helps a smidge

alex

indy · Post by **indy** » Wed Jan 16, 2013 4:16 pm

Davidov wrote:I got that in my gen 3 as well if i understand you correctly.
For example crawling around in a carpark, if i come off the accelerator the car will lurch/buck. Makes carpark driving quite uncomfortable. Never bothered to look into it but.

Yeh David sounds like the exact problem I'm encountering, most of my driving is around town and this drives me nuts when it happens lol.

Alex, it does feel more so like a mechanical hop, I'm going to get my friend to have a look at engine mounts, transmission and rear diff to try and eliminate those. When it happens usually the revs jump up and down with the bucking (only slightly though).

When I get a bit more coin I'll get a new gasket set for the valve covers & leads just to eliminate that as a possibility, but it does feel more of a mechanical type of hop.

Post by **Alex** » Wed Jan 16, 2013 4:25 pm

does it idle okay?

fuel filter is another possibilty (not cheap unfortunately)

alex

indy · Post by **indy** » Wed Jan 16, 2013 6:06 pm

Alex wrote:does it idle okay?

fuel filter is another possibilty (not cheap unfortunately)

alex

Yeh it idles fine alex, and i replaced the fuel filter a week ago to eliminate that as a possibility and it still happens.

AlpineRaven · Post by **AlpineRaven** » Wed Jan 16, 2013 6:46 pm

I think you might be referring to "jerky" feel in low revs in gears - I did have that issue in my gen2 Liberty as well got used to it...
Swap MAP sensor Air Control unit on the airbox see how it goes...
Cheers
AP

indy · Post by **indy** » Wed Jan 16, 2013 7:36 pm

AlpineRaven wrote:I think you might be referring to "jerky" feel in low revs in gears - I did have that issue in my gen2 Liberty as well got used to it...
Swap MAP sensor Air Control unit on the airbox see how it goes...
Cheers
AP

By swap do you mean is there 2 MAP sensors in the car that i can swap around? or would i need to purchase a new one? if so are they relatively cheap?

Just looking in the Factory Service Manual and can't seem to find MAP sensor?

Sorry i'm new to the world of fuel injected subys.

YouTube · Post by **El_Freddo** » Wed Jan 16, 2013 9:11 pm

I'm thinking it has more to do with the clutch and flywheel weight, maybe even the IACV.
The Idle Air Control Valve might need cleaning out.

As for the bucking, my thoughts are that it is the load of the engine being dropped off and "catching" the coasting of the car, which then plays on the springs in the clutch disc. Once these are compressed or stretched the car will lurch and jerk around until it balances out. A quick on/off action on the throttle lightly can induce the same thing again.

Ruby Scoo does it a bit and I live with it by doing as you say - press the clutch pedal and release it again (controlled).

As for the shudder, does it happen when you're using the clutch? If so it's a build up of the clutch disc's dust that hasn't had the chance to clear the area of contact. Slipping the clutch occasionally will help clear this crap and you'll have smooth clutch action once again. I've also had this happen to me as I double clutch on down changes and don't really slip the clutch on take off. Works a treat for me!

Cheers

Bennie

Post by **TOONGA** » Wed Jan 16, 2013 9:16 pm

warped flywheel or one of those horrific dual mass flywheels.

or the IVAC might need a couple of cans of S.U.C.C.

TOONGA

Davidov · Post by **Davidov** » Wed Jan 16, 2013 10:58 pm

Does your IACV make a wierd whirring sort of sound when you switch the car off? Mine did and I'm not sure if that's normal but it could have played a part.

tambox · Post by **tambox** » Thu Jan 17, 2013 7:47 am

My Gen 3 outback did that intermittantly. Its something to do with the engine control system. I started to look into it, but sold it instead:p.
The IACV gets dirty, remove it and clean it.
As mine did it with a very gentle touch of the accelerator, the motor "surges" and is not smooth, I also thought it may be the TPS wearing/getting dirty at its initial movemnet point. These things are are wiper arm on a carbon strip, they wear and the resistance jumps all over the place, confusing the the CPU. I also thought it might be the idle contacts in the TPS, but I checked and ajusted those, to no effect.

Good luck, its a pain when it does this.

indy · Post by **indy** » Thu Jan 17, 2013 1:16 pm

Davidov, not to sure about a noise. Only noise i really notice is the fuel pump when turning the car on, will listen next time with the bonnet open upon turning the car off.

Some good suggestions, already cleaned the IACV a week ago, i'll clean it again although this time will get a can of Subaru Upper Engine Cleaner as suggested and run that through.
So far i think El freddo's explanation makes alot of sense regarding the clutch, it does feel more mechanical than fuel/spark related, and a touch of accelerator or putting the clutch in seems to correct it.
I believe it still has the original Dual Mass Flywheel in it, although i'm not sure as it didn't come with log books/service history and has done 197km's.

RX Coupe · Post by **RX Coupe** » Fri Jan 18, 2013 12:26 pm

My Gen 3 Outback was fine until I needed a new clutch and replaced the dual mass flywheel with a solid one. I noticed straight away the gearbox making more noise under acceleration and jerking when going down hills in low gears or backing off the accelerator. Sometimes it would also jerk a little under acceleration.

Subyroo · Post by **Subyroo** » Fri Jan 18, 2013 10:19 pm

RX Coupe wrote:My Gen 3 Outback was fine until I needed a new clutch and replaced the dual mass flywheel with a solid one.

I went through the same process with my 03 XS Forester and have the "jerks" when crawling along in stop - go traffic.
It's not real bad but enough to give you the shits if you are in stop - go for a long distance.

thunder039 · Post by **thunder039** » Sat Jan 19, 2013 9:29 am

i have the same thing in my forester. it was a lot worse with my old engine and have delt with it in same way by prssing on the clutch. the new engine is not as bad but still does it, but in saying that i could have just gotton used to it.
it does make you look like a total manual newby in the car parks for sure lol

indy · Post by **indy** » Sat Jan 19, 2013 10:18 am

RX Coupe wrote:My Gen 3 Outback was fine until I needed a new clutch and replaced the dual mass flywheel with a solid one. I noticed straight away the gearbox making more noise under acceleration and jerking when going down hills in low gears or backing off the accelerator. Sometimes it would also jerk a little under acceleration.

Subyroo wrote:I went through the same process with my 03 XS Forester and have the "jerks" when crawling along in stop - go traffic.
It's not real bad but enough to give you the shits if you are in stop - go for a long distance.

thunder039 wrote:i have the same thing in my forester. it was a lot worse with my old engine and have delt with it in same way by prssing on the clutch. the new engine is not as bad but still does it, but in saying that i could have just gotton used to it.
it does make you look like a total manual newby in the car parks for sure lol

The crawling in stop go traffic and car parks is what really bugs me, whenever I'm driving people around they think i'm just a complete manual retard lol.
I'm starting to learn to drive around it, being smoother, clutch in and out when i feel it start happening etc.
It seems that its quite a common problem, i wasn't expecting so many people to have it aswell in this thread.

I thought it may be just a case of the Dual Mass flywheels that came standard in the GEN3 outbacks, but as RX coupe noted his became prominent after converting to a solid flywheel.

Thunder, is yours still a Dual Mass or has it been converted to a solid flywheel?

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thunder039 · Post by **thunder039** » Sat Jan 26, 2013 9:25 am

It's standard so I think it would be solid?

indy · Post by **indy** » Sun Jan 27, 2013 3:35 pm

Thunder, i believe the 01 Outbacks came with a Duall Mass flywheel.
Had my cousin who is a plant mechanic have a look at it the other day, he drove it and it happened to him, he seems to think its definitely not fuel/spark related and also thinks its the more then likely the clutch, but i should check then engine mounts just to rule them out. Just going to learn to live with it until the clutch actually gives in.