Solved: amp is making the mystery droning motor sound

[bloc]

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.

What if the pulley ratio is too low to adequately drive the compressor at the low idle?

What if the required torque at the lower idle would introduce vibrations the NVH nerds didn’t find acceptable?

For the record it is possible for that to be a narrow window. Ie the torque converter could require enough torque that things dampen out again.

End of the day, we don’t know.

And without knowing the reasons for doing what they did, it’s pretty tough to take someone seriously that claims an engineering department the size of Toyota’s could have done something but didn’t.

I can’t speak to the transmission.. the short drive I took in an 8spd was great.

 

[Grumvee]

Hi Mud!

I really wanted to figure this out, so I went at it today. I assumed (based on my back and forth with @bloc) that it was a fan in the nav unit. It is not.

Turns out it is NOT coming from the dashboard at all.

As I started disassembling the dashboard, it became more clear that the sound was coming from around the shifter. So I disassembled all of those bits. I don't see any motors or anything in there that it could be.

So then I started looking UNDER the vehicle, and I can as clearly hear the sound from there... in the area roughly under the shifter.

Here are some pictures / videos:

• Video showing where the sound is coming from, from the top side (shifter area)
• Video showing where the sound is coming from, from the bottom side
• Picture of the general area, from the bottom side (highlights show where sound is coming from)

I double checked that pulling the driver's side fuse #3 7.5A for "ACC" still causes the sound to stop. It does. I find this strange since the fuse lists the following systems, none of which seem like they would be related to the sound:

1. Audio system
2. Parking assist system
3. Multi-display assembly
4. Gateway ECU
5. Main body ECU
6. Mirror ECU
7. Satellite radio
8. Smart access system with push button start

Other relevant info:

• Climate control system is turned to OFF (so it's not that)
• Coolbox is set to OFF (it has been inoperative since I bought the vehicle a few years ago)
• TechStream is not throwing any codes (other than things I already know about, such as passenger seat ECU not working; sunroof fuse disconnected because it leaks and I sealed it closed)

I'm not sure where to go next, and thought I'd stop and get your thoughts.

Thx!

GRUMVEE

P.S. Somehow this thread got split and there is a side conversation about the 5.7 tuning, idling, etc. If folks don't mind moving that to a separate thread if they want to continue that conversation, that should help keep things cleaner. Thx!

 

[Grumvee]

My mechanic figured it out: the sound is coming from the stereo amplifier under the driver’s seat, apparently.

The stereo works fine.

I guess I’ll look on eBay to see how much a used replacement would be, as the sound is driving me a little nuts.

Anyone ever heard of this issue?

 

[grinchy]

There are fans on the amplifier. They’ve been replaced on the forum before.

 

[05ls430518]

Move the carpet and vacume all the s*** by the fan exhaust. My amp was cutting out making a humming sound all that. The route cause was a ton of crap blocking/coming into contact with the fans so they could not work properly.

If you go a repaired amp route send it to Joe at oem audio. He is awesome I have sent other LX and Lexus owners to him and he fixed there stuff no problem and saved people thousands. Link below to him.

oem audio ny - Google Search

 

[Grumvee]

Thx @05ls430518!

Great info.

I will try vacuum as an easy step 1!