Solved: amp is making the mystery droning motor sound (1 Viewer)

[Grumvee]

Mud - can you help me solve this mystery?

I’m hearing a droning sound coming from what sounds like the top of the dashboard … or somewhere in that direction. Sounds like a motor that is continually running.

Starts when the engine starts. Does not happen if ignition is on without engine on.

Happens regardless of climate control settings, and even if climate control is OFF.

I can’t hear anything from the engine compartment but then again the engine is so loud, that’s not surprising if the sound is emanating from engine compartment.

Seems to run for a long time but eventually shuts off.

Here’s a video that demonstrates the sound. I set the phone on the dashboard. You will need to turn volume up to hear it well.

Any ideas?

Thx!

 

[grinchy]

when a temp sensor wire gets unplugged, the fan will run on high?
Or you have water leak and your fan is shorted on?

THe fan is under/behind the glovebox

 

[bloc]

A number of people have reported this issue. Usually more prevalent when things get cold.

I believe it is a cooling fan in the back of the nav unit with worn out bushings, though I have no evidence. This allows the fan and shaft to wobble around and lose speed, stopping the wobble, then speed up again to start it. Over and over.

 

[2021 LC200]

Not clear problem mentioned relates to the following. Apologize in advance.

What I do experience on my LC200 is high initial idle rev at around 1500 to 1800 rpm, probably depending on outside temperature, for a less than pleasant start up experience (and kind of droning sound for 10 seconds or so). Seems Toyota has programmed the engine ECU to accelerate exhaust heat up and cat functioning. Wish they had not made it this extreme, more like 1100 to 1200 rpm then dropping to regular idle of 600 to 800.

As we are talking about engine and transmission management;
- Annoying to see and hear idle jump from 600 to 900 when the cooling fan and/or AC compressor activates. Happens in Houston weather about every 20 to 30 second when idling. Imagine the same in the land down under and middle east, so go figure... This with proper ECU programming should not be required at all.
- Cruise control, engine and transmission management during set speed and going over minor inclinations or high way bridges. Both uphill downshifting and equally ridiculous downhill down shifting to 3000rpm or so. Really Mr T...
- Torque converter lock up management

Compared to my BMW F10 535d this is all a joke.

I wonder if this actually could be programmed properly...

Oh well, I am still in love with my LC200. Many, many things I like a lot. Could yet be (so) much better with an otherwise beast of an engine and 8sp auto.

 

[scott johnson]

if it sounds like its coming from the passenger side open the glove box and listen. the dvd for the nav is pretty loud.

 

[1Maverick]

Not clear problem mentioned relates to the following. Apologize in advance.

What I do experience on my LC200 is high initial idle rev at around 1500 to 1800 rpm, probably depending on outside temperature, for a less than pleasant start up experience (and kind of droning sound for 10 seconds or so). Seems Toyota has programmed the engine ECU to accelerate exhaust heat up and cat functioning. Wish they had not made it this extreme, more like 1100 to 1200 rpm then dropping to regular idle of 600 to 800.

As we are talking about engine and transmission management;
- Annoying to see and hear idle jump from 600 to 900 when the cooling fan and/or AC compressor activates. Happens in Houston weather about every 20 to 30 second when idling. Imagine the same in the land down under and middle east, so go figure... This with proper ECU programming should not be required at all.
- Cruise control, engine and transmission management during set speed and going over minor inclinations or high way bridges. Both uphill downshifting and equally ridiculous downhill down shifting to 3000rpm or so. Really Mr T...
- Torque converter lock up management

Compared to my BMW F10 535d this is all a joke.

I wonder if this actually could be programmed properly...

Oh well, I am still in love with my LC200. Many, many things I like a lot. Could yet be (so) much better with an otherwise beast of an engine and 8sp auto.

The cruise control is my biggest complaint. It‘s the worst I’ve ever used. I just use it on long straight stretches of flat to low rolling hills.

 

[bloc]

- Annoying to see and hear idle jump from 600 to 900 when the cooling fan and/or AC compressor activates. Happens in Houston weather about every 20 to 30 second when idling. Imagine the same in the land down under and middle east, so go figure... This with proper ECU programming should not be required at all.

If I were to guess: 600 for NVH and saved fuel/emissions/trans temp, 900 for adequate refrigerant pressure/effectiveness.

Doesn’t seem like any ECU programming can defeat those requirements, so it alternates between the necessary conditions.

 

[2021 LC200]

If I were to guess: 600 for NVH and saved fuel/emissions/trans temp, 900 for adequate refrigerant pressure/effectiveness.

Doesn’t seem like any ECU programming can defeat those requirements, so it alternates between the necessary conditions.

There are many vehicles which do not do this including my 535d. Rather they then would set it up at 800 rpm idle and keep the same AC on or not. Oh well.

 

[bloc]

There are many vehicles which do not do this including my 535d. Rather they then would set it up at 800 rpm idle and keep the same AC on or not. Oh well.

Another guess: a diesel has way more torque at a low idle to run a compressor without any noticeable consequences for passengers. Also a much lower redline that can impact pulley sizing and as a result compressor rpm at idle.

Plus not sure about BMW but many euro cars use variable displacement compressors that don’t have a clear on-off cycle. Toyota prefers a clutched compressor, and if I had to make assumptions like many of their decisions it has to do with reliability.

Just thinking through this.

Personally I notice the idle change and it doesn’t bother me one bit.

 

[2021 LC200]

Another guess: a diesel has way more torque at a low idle to run a compressor without any noticeable consequences for passengers. Also a much lower redline that can impact pulley sizing and as a result compressor rpm at idle.

Plus not sure about BMW but many euro cars use variable displacement compressors that don’t have a clear on-off cycle. Toyota prefers a clutched compressor, and if I had to make assumptions like many of their decisions it has to do with reliability.

Just thinking through this.

Personally I notice the idle change and it doesn’t bother me one bit.

Thanks for pointing out, I think you are right. After two years and about 22k miles I am getting used to it although it makes me want to shut down the car and walk into the supermarket instead of calmly waiting and listening to some music or forever keeping up with my smartphone and work + surplus info on there...

Out of curiosity I looked up torque curves of the N57 3lts 6 diesel and the 3UR-FE 5.7ltr V8. The US F10 535d = EU F10 530d has about 250 ft lbs at idle, although the graph extrapolation at low end has of course quite a bit of uncertainty. The 3UR-FE has about 380 NM or 280 ft lbs at idle. Rest can be managed with good motor management. Even 1 ltr small cars drive pretty good these days and stick shift/clutch wise are not difficult to drive any longer. Variable valve timing, fuel injection and motor management of the last 20 to 30 years has been great.

As you say BLOC, how the AC compressor works and its size matters as well. I would expect the LC200 compressor is (much) bigger since I know it cools the vehicle very well. I also tried to figure out whether my 535d Denso AC compressor is variable displacement. Did not find explicit info on that but would agree with you it is very likely. So this may just be the reason for the more sophisticated experience in the 535d to the slightly more intrusive experience of the cruiser. Maybe I just need to sit there in Drive mode and keep the foot on the break keeping the rpm nice at 600... I know, that would be crazy Makes me think though the AC compressor is keeping up at 600 to 700 rpm. Oh well, going in circles here.

I know I am just complaining about an otherwise great vehicle which I would not want to miss for just about anything.

I do wish, since I plan to keep it 20year plus, that there is a tuner who could tweak that by adjusting some of the ECU maps while not fiddling with fuel to air ratios or timing etc. Fix the cruise control engine downshift on small inclines and declines and torque converter lock up behaviour in the process... I rest my case and know I have to accept the way it is.

 

[bloc]

Thanks for pointing out, I think you are right. After two years and about 22k miles I am getting used to it although it makes me want to shut down the car and walk into the supermarket instead of calmly waiting and listening to some music or forever keeping up with my smartphone and work + surplus info on there...

Out of curiosity I looked up torque curves of the N57 3lts 6 diesel and the 3UR-FE 5.7ltr V8. The US F10 535d = EU F10 530d has about 250 ft lbs at idle, although the graph extrapolation at low end has of course quite a bit of uncertainty. The 3UR-FE has about 380 ft lbs at idle which given its coffee pot sized cylinders and significant stroke makes sense. Seems almost proportional to displacement, which ball park first order adds up. Rest can be managed with good motor management. Even 1 ltr small cars drive pretty good these days and stick shift/clutch wise are not difficult to drive any longer. Variable valve timing, fuel injection and motor management of the last 20 to 30 years has been great.

We are then back to how the AC compressor works and its size. I would expect the LC200 compressor is (much) bigger since I know it cools the vehicle very well. I also tried to figure out whether my 535d Denso AC compressor is variable displacement. Did not find explicit info on that but would agree with you it is very likely. So this may just be the reason for the more sophisticated experience in the 535d to the slightly more intrusive experience of the cruiser. Maybe I just need to sit there in Drive mode and keep the foot on the break keeping the rpm nice at 600... I know, that would be crazy Makes me think though the AC compressor is keeping up at 600 to 700 rpm. Oh well, going in circles here.

I know I am just complaining about an otherwise great vehicle which I would not want to miss for just about anything.

I do wish, since I plan to keep it 20year plus, that there is a tuner who could tweak that by adjusting some of the ECU maps while not fiddling with fuel to air ratios or timing etc. Fix the cruise control engine downshift on small inclines and declines and torque converter lock up behaviour in the process... I rest my case and know I have to accept the way it is.

View attachment 3231187


View attachment 3231189

There is no way a 3UR only makes 10ft-lbf off its peak torque at idle.

Your displacement argument is plausible but I thought a gas engine being air restricted at idle and a diesel not may have made up for the difference.

Not to mention this vehicle was primarily developed for the rest of the world, not the US, and a luxury German sedan it is not, despite the price.

Either way, seems like you are getting my point. It’s a great vehicle and if these are the things we have to complain about….

 

[2021 LC200]

There is no way a 3UR only makes 10ft-lbf off its peak torque at idle.

Your displacement argument is plausible but I thought a gas engine being air restricted at idle and a diesel not may have made up for the difference.

Not to mention this vehicle was primarily developed for the rest of the world, not the US, and a luxury German sedan it is not, despite the price.

Either way, seems like you are getting my point. It’s a great vehicle and if these are the things we have to complain about….

I think you are looking at the wrong curve BLOC. It is the purple one at 405 ft lbs and 1000rpm, therefore around 380 ft lbs at 600 or the nearest questimate of your liking. That is the horse power = torque x rpm and is around 40 HP at 1000 rpm, diesel or gas.

 

[bloc]

I think you are looking at the wrong curve BLOC. It is the purple one at 405 ft lbs and 1000rpm, therefore around 380 ft lbs at 600 or the nearest questimate of your liking. That is the horse power = torque x rpm and is around 40 HP at 1000 rpm, diesel or gas.

The published peak torque of a 3UR in a land cruiser is 391ft-lbf, nowhere close to the approx 540 on that chart. Where did you source that? That looks more like a supercharged example.

 

[2021 LC200]

The published peak torque of a 3UR in a land cruiser is 391ft-lbf, nowhere close to the approx 540 on that chart. Where did you source that? That looks more like a supercharged example.

Excellent point. You are right, my mistake. Got this actually from IH8MUD but missed to notice the kilo Watt and NM annotation. That changes the comparison quite a bit, although I remain Mr T's ECU programmers should visit Munich, drink some good beer and make things better, yet do not copy how they manufacture them...

 

[bloc]

drink some good beer and make things better, yet do not copy how they manufacture them...

Agreed completely.

 

[Tex68w]

The cruise control is my biggest complaint. It‘s the worst I’ve ever used. I just use it on long straight stretches of flat to low rolling hills.

I agree, they have the worst radar cruise of any on the market that I’ve driven.

 

[Grumvee]

I believe it is a cooling fan in the back of the nav unit with worn out bushings, though I have no evidence. This allows the fan and shaft to wobble around and lose speed, stopping the wobble, then speed up again to start it. Over and over.

Hi @bloc. I think you're correct!

I had some of the dashboard bits off today, and that's the general place the sound seems to be coming from. More on the left side vs. the right side.

I tried turning the screen off and waiting to see if the fan would stop running. It didn't.

So then I started pulling out fuses for the radio / multi-display ... and I located one (driver's side fuse #3 7.5A for "ACC") that, when pulled, stops the sound. It also blanks the screen and makes it inoperable. Screenshot below showing the specific fuse.

All that said, I don't know how to FIX the problem.

Or whether simply leaving it (and dealing with the sound) will lead to any issues down the line. Thoughts on that?

Best,

Grumvee

 

[bloc]

Hi @bloc. I think you're correct!

I had some of the dashboard bits off today, and that's the general place the sound seems to be coming from. More on the left side vs. the right side.

I tried turning the screen off and waiting to see if the fan would stop running. It didn't.

So then I started pulling out fuses for the radio / multi-display ... and I located one (driver's side fuse #3 7.5A for "ACC") that, when pulled, stops the sound. It also blanks the screen and makes it inoperable. Screenshot below showing the specific fuse.

All that said, I don't know how to FIX the problem.

Or whether simply leaving it (and dealing with the sound) will lead to any issues down the line. Thoughts on that?

Best,

Grumvee

View attachment 3232325

If it is a cooling fan not working correctly I’d have to wonder if the nav unit is getting the air it needs. This may be balanced out by it seeming to be more prevalent in cold weather when there may not need to be as much airflow in the first place.

But if it does turn out to be the fan I think taking the unit apart and replacing the internal fans is the ultimate fix. This sounds super involved but in my experience with these AV systems it’s usually a pretty simple metal case screwed onto the outside of all the complex bits. Shouldn’t be too difficult to do.. though sizing and sourcing the fans won’t happen immediately so you may be looking at down time, or stripping it all down and reassembling twice. Once to measure, another to install.

I had mine out to fix a bad knob and seem to remember there being two fans, one on each side. But I could be wrong on that.

Good work on narrowing it down with fuses though. I planned to do that if I ever dealt with the noise but so far haven’t had that problem.

 

[TeCKis300]

Having tuned idle, both standalones and factory ECUs, none of the behavior above is unexpected. Fast idle for cold start, idle up for A/C, and even idle up for the hydraulic steering pump - those have existed even back in more analog systems. ECUs do it by explicit RPM targets to open up the throttle body for idle. It's not the result of bad programming. It's the balance between emissions, fuel economy, and necessary output to support loads.

The 5.7L is a big truck engine. Supporting big truck components. It's what you get and that is its nature. The LX is more refined in this regard with more isolation (engine covers, sound damping), and probably a better comparison for a BMW. But it is still a large motor and let's you know it's starting up and in charge. I don't mind that. The 300-series probably does it better, but then purists may miss the "character" of these "older" cars.

 

[2021 LC200]

Sorry, I am of the opinion the 5.7 has plenty of torque to idle lower at initial startup or run the AC compressor at 700 to 800 rpm, as that is the same speed the engine turns when you engage Drive and can easily drive off. Just a matter of proper ECU programming and maybe an additional sensor or two. The fact that other brands can do so and the LC200 5.7 engine and gearbox is all over the place (down shifting) going up and down bridge with slide inclines just shows how simple they have the setup.

I remain disappointed in that part despite all the Toyota goodness and enjoyment of the LC200 otherwise.