AVCS noise - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Yfzr750 · 10-07-2019, 06:49 AM

Good day all. Hope everyone and their cars are well.

I recently started hearing a ticking/tapping noise coming from my engine, its really audible inside the car. But under the hood it's just barely a bit louder than the direct injectors.
Coming from the aircon pump area.
And its only heard when the engine is hot and between idle and 2000rpm. After that it disappears. And a bit louder on a hot startup for about 3 seconds then it eases quiter.

I checked the valve clearences on this side and they are within spec, nothing odd looking on the lifters. And while I was there, I removed the spark plugs and used something to push down on the pistons after I rotated the crank to the point the pistons we're traveling down. And zero movement so it's not rod knock.

I recently replaced the cam chain tensioners, so my only other guess is one of the Avcs gears are probably acting up.

Has anyone else had issues with a similar noise?

I would like to open it up and clean the Avcs gears out but I haven't found a clear guide on how to do it properly on this specific gear. Is there maybe a tutorial I'm missing? I don't want to cause damage to something I could have avoided.

Thanks in advance!

churchx · 10-07-2019, 08:00 AM

By chance, it's not when you quickly floor go-pedal? I'd check if direct injector seals are OK.

Yfzr750 · 10-07-2019, 08:04 AM

Not at all. Only from idle to 2000rpm. Otherwise its completely silent and smooth above it.

churchx · 10-07-2019, 08:11 AM

As you are from South Africa as location from your profile, which i heard often mentioned as having very bad quality fuel resulting lot of timing retardation even with low IAM, my second guess if that isn't some knocking.

Yfzr750 · 10-07-2019, 08:25 AM

That's 100% true. Fuel is bad, I heard it have some detonation one day while driving. But it's different to what I'm hearing now... It follows rpm, irrespective of throttle position.
To my understanding and experience detonation mostly occurs during acceleration and can be silenced when slacking off the pedal.
Would the fuel system be okay with adding a bit of octane boost to test it?

But it's a bit strange because its sounds to be at the front of the engine, close to the Avcs gear. Near to the High pressure pump.

Yfzr750 · 10-07-2019, 08:32 AM

This is the only thread I found that's close to what I'm experiencing, but they are saying it's normal.
https://www.ft86club.com/forums/showthread.php?t=39734

Yfzr750 · 10-07-2019, 01:14 PM

Okay, I added fresh fuel, still noisy.
So I dropped the oil pan and bearings feel good. Just one has a bit extra side to side movement.
I guess the next step is to remove the front cover and inspect.

Yfzr750 · 10-13-2019, 06:25 AM

Hi Everyone. Took everything apart, still couldn't manage to find a problem.

Has anyone experienced a problem with the Avcs making a rattling noise at idle when hot? Sounds like mine is on the intake cam on the high pressure pump side

solidsnake11 · 10-13-2019, 10:33 PM

Which rod has excessive side clearance?

Ultramaroon · 10-13-2019, 11:42 PM

Quote:

Originally Posted by solidsnake11

Which rod has excessive side clearance?

I thought about you reading that earlier.

Yfzr750 · 10-14-2019, 06:03 AM

Quote:

Originally Posted by solidsnake11

Which rod has excessive side clearance?

Cylinder 3. It's not exessive, still within the specifications. But the others are much tighter.

solidsnake11 · 10-14-2019, 06:41 AM

Quote:

Originally Posted by Yfzr750

Hi Everyone. Took everything apart, still couldn't manage to find a problem.

What is everything?

Just worked on a honda that had a peck. I was hoping it was a valve but it wound up being a rod bearing.

Yfzr750 · 10-14-2019, 07:03 AM

Quote:

Originally Posted by solidsnake11

What is everything?

Just worked on a honda that had a peck. I was hoping it was a valve but it wound up being a rod bearing.

Ouch, hope it's not too badly hurt.
Not everything sorry, but front cover, oil pan and the lower carrier part that the oil pan bolts to.

solidsnake11 · 10-14-2019, 03:45 PM

Well I put a new set of rod bearings in it. Crank was in great shape but Im not so sure about the big end of the rod. Peck went away for now. Replaced them in car(honda).

Is the engine in the car? Just wanted to know it was possible to get lower carrier part off in the car. You can take the rod cap off and see what the bearings looks like.
It might be possible to change the rod bearings in the fa20 without splitting the case but I have not did it so I'm not for sure.

10-07-2019, 06:49 AM	#1
Yfzr750 Member Join Date: May 2019 Drives: Toyota 86 Location: Southa Africa Posts: 11 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	AVCS noise Good day all. Hope everyone and their cars are well. I recently started hearing a ticking/tapping noise coming from my engine, its really audible inside the car. But under the hood it's just barely a bit louder than the direct injectors. Coming from the aircon pump area. And its only heard when the engine is hot and between idle and 2000rpm. After that it disappears. And a bit louder on a hot startup for about 3 seconds then it eases quiter. I checked the valve clearences on this side and they are within spec, nothing odd looking on the lifters. And while I was there, I removed the spark plugs and used something to push down on the pistons after I rotated the crank to the point the pistons we're traveling down. And zero movement so it's not rod knock. I recently replaced the cam chain tensioners, so my only other guess is one of the Avcs gears are probably acting up. Has anyone else had issues with a similar noise? I would like to open it up and clean the Avcs gears out but I haven't found a clear guide on how to do it properly on this specific gear. Is there maybe a tutorial I'm missing? I don't want to cause damage to something I could have avoided. Thanks in advance!

10-14-2019, 03:45 PM	#14
solidsnake11 Senior Member Join Date: Nov 2018 Drives: brz Location: nc Posts: 318 Thanks: 431 Thanked 739 Times in 443 Posts Mentioned: 24 Post(s) Tagged: 0 Thread(s)	Well I put a new set of rod bearings in it. Crank was in great shape but Im not so sure about the big end of the rod. Peck went away for now. Replaced them in car(honda). Is the engine in the car? Just wanted to know it was possible to get lower carrier part off in the car. You can take the rod cap off and see what the bearings looks like. It might be possible to change the rod bearings in the fa20 without splitting the case but I have not did it so I'm not for sure. Last edited by solidsnake11; 10-14-2019 at 10:37 PM.

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10-07-2019, 08:00 AM	#2
churchx Senior Member Join Date: Mar 2015 Drives: 2014 GT86 Location: Latvia, Riga Posts: 4,333 Thanks: 696 Thanked 2,085 Times in 1,436 Posts Mentioned: 53 Post(s) Tagged: 1 Thread(s)	By chance, it's not when you quickly floor go-pedal? I'd check if direct injector seals are OK.

10-07-2019, 08:04 AM	#3
Yfzr750 Member Join Date: May 2019 Drives: Toyota 86 Location: Southa Africa Posts: 11 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Not at all. Only from idle to 2000rpm. Otherwise its completely silent and smooth above it.

10-07-2019, 08:11 AM	#4
churchx Senior Member Join Date: Mar 2015 Drives: 2014 GT86 Location: Latvia, Riga Posts: 4,333 Thanks: 696 Thanked 2,085 Times in 1,436 Posts Mentioned: 53 Post(s) Tagged: 1 Thread(s)	As you are from South Africa as location from your profile, which i heard often mentioned as having very bad quality fuel resulting lot of timing retardation even with low IAM, my second guess if that isn't some knocking.

10-07-2019, 08:25 AM	#5
Yfzr750 Member Join Date: May 2019 Drives: Toyota 86 Location: Southa Africa Posts: 11 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	That's 100% true. Fuel is bad, I heard it have some detonation one day while driving. But it's different to what I'm hearing now... It follows rpm, irrespective of throttle position. To my understanding and experience detonation mostly occurs during acceleration and can be silenced when slacking off the pedal. Would the fuel system be okay with adding a bit of octane boost to test it? But it's a bit strange because its sounds to be at the front of the engine, close to the Avcs gear. Near to the High pressure pump.

10-07-2019, 08:32 AM	#6
Yfzr750 Member Join Date: May 2019 Drives: Toyota 86 Location: Southa Africa Posts: 11 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	This is the only thread I found that's close to what I'm experiencing, but they are saying it's normal. https://www.ft86club.com/forums/showthread.php?t=39734

10-07-2019, 01:14 PM	#7
Yfzr750 Member Join Date: May 2019 Drives: Toyota 86 Location: Southa Africa Posts: 11 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Okay, I added fresh fuel, still noisy. So I dropped the oil pan and bearings feel good. Just one has a bit extra side to side movement. I guess the next step is to remove the front cover and inspect.

10-13-2019, 06:25 AM	#8
Yfzr750 Member Join Date: May 2019 Drives: Toyota 86 Location: Southa Africa Posts: 11 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Hi Everyone. Took everything apart, still couldn't manage to find a problem. Has anyone experienced a problem with the Avcs making a rattling noise at idle when hot? Sounds like mine is on the intake cam on the high pressure pump side

10-13-2019, 10:33 PM	#9
solidsnake11 Senior Member Join Date: Nov 2018 Drives: brz Location: nc Posts: 318 Thanks: 431 Thanked 739 Times in 443 Posts Mentioned: 24 Post(s) Tagged: 0 Thread(s)	Which rod has excessive side clearance?

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