2006 Avensis 1.8 Petrol - Engine roughness

[MikeEH]

Ever since I bought the car just over 3 years ago, I've noticed that when I reach and exceed 3000rpm, the engine exhibits a roughness, with a noticeable vibration through the floor and steering wheel. This is not a car motion problem as it happens if revving the car when stationary. I've read of this problem on other net forums but no-one has come up with an answer. Is there still no answer?

Thanks.

[ents]

That can be caused by many things. The VVT kicks in around that rpm range, perhaps this causes your problems. And this system also changes ignition timing, so in higher revs the lambda sensors could give false reading to the ECU and mess up the air/fuel ratio, that can cause vibrations.

Perhaps a full diagnostic check will lead you to your trouble maker.

[MikeEH]

Thanks, I'll see about a diagnostic check.

[MikeEH]

Had a diagnostic check done yesterday. The bloke took a ride in the car to experience the roughness/vibration, but couldn't find anything wrong diagnostically. He spent from 2.00pm to 4.45pm trying to find the problem. He's contacting an old mate who worked in a Toyota garage to see if he remembers anything similar. The roughness/vibration gets worse with engine load, ie., when stationary, it's mild, when accelerating it's really noticeable, and when climbing hills in 2nd or 3rd gear it's pretty bad. If his mate doesn't come up with anything, it'll be a case of just getting used to it I think.

[frankie406]

How many miles on it?? 

And as ents has said could be the vvt coming into play.possibly a pully or a slack chain.

[TomdeGuerre]

Sounds like a head gasket leaking to me, possibly between two cylinders. Doesn't always show up during static testing but starts when engine is put under load.

 

[MikeEH]

This problem was on the car when I bought it 3 and a half years ago, when the mileage was 60K ish. Didn't notice it on test drive as I probably didn't exceed 3K revs. Got Citizens Advice involved to try to get my money back from showroom, but failed - car was deemed fit for purpose. It's on just over 100k now, and the problem hasn't got worse nor better...still the same.

Not using any water - never topped it up, nor oil, which is changed every 6000 miles. The problem only happens between 3000rpm and about 4.500rpm. When engine is under load below 3000K there is no problem. It also occurs when stationary and revving between 3 and 4.5K revs - so engine not really under load when stationary. If it were head gasket, surely the problem would continue to occur over 4.500 revs?  There is no timing chain rattle/noise at all, in fact, engine is so quiet I often stall at lights, or try to (re) start the engine.

This problem with the Toyota vvt engined Avensis has been on quite a few car owner forums, and most owners appear to think it only happens when moving, as they've changed wheels, tyres, drive-shafts, etc., with no luck. As it happens when stationary, it can only be engine related.

[frankie406]

Have the injectors checked and plugs/coils. 

[Konrad C]

Has the crank pulley and the flywheel ever been changed? Anything could have happened before you bought the car. I would look at the cam and crank sensors too. 

When I had my old Mk1, the vibration damper on the exhaust fell off, due to the mounts point corroding. The vibration at 1600 and 2600 rpm was bad. I found the damper, and clamped it using 'U' clamps. This was mostly worked with only a small resonance still there. It disappeared when I changed the exhaust and re-fitted the damper. Now that could a cause - the exhaust.  On the inlet side check the resonator.

Too much variables! 

[MikeEH]

I'm contacting the diagnostic place next week so I'll ask about the coils, (plugs are new), and the cam and crank sensors. I'll ask if he checked these, if not will get him to check now. Will also check exhaust damper. Thanks.

 

[gazza1286]

Has anybody suggested cleaning the MAF sensor? The procedure is simple and might cure the rough running. 

 

[fordulike]

I agree, this site suggests it might be worth a go:

http://www.mafcleaning.co.uk

[MikeEH]

The coil and plugs were checked during the diagnostic, and the MAF sensor was temp replaced with a known good one. Didn't cure the problem. If it was the cam/crank sensor, wouldn't it complain at any rev and not just over 3000rpm? The diagnostic man contacted his ex Toyota mechanic friend, but he'd not come across this problem. Prob too expensive hour-wise to take an out of warranty car to a dealership for repair.....We haven't checked the exhaust damper yet, but at the mo, he believes it's a problem with the vvt, as he was told that it kicks-in around 3000rpm.

[gazza1286]

Have you removed the VVT oil control valve? The associated oil filter may have clogged. It's a 20 minute job. 

 

[MikeEH]

That might be worth checking. Any idea where I should start looking for it/them?

[gazza1286]

There is only one on the Avensis. It's in exactly the same place as on this link. Be careful when disconnecting the wiring as the connector on the OCV is delicate. 

 

[MikeEH]

Thanks, I'll have a look at this.

[Handel]

Hi MikeEH,

Did you able to find what was the issue? Cause I have the same vibration stationary after 2000rpm and I was in dealar and several more mechanics and noone able to find what is wrong with the car.