Your sound clip sounds like its working.. I did mine under the car as one connector in each side. Not heard of doing it in the trunk, many many articles on the underside, but do know they make a controller to do it your way. Yes when they didn't work last week, then plugged both back in, started car for a bit, then with car completely shut down & key way away the car then un-did drivers side and could fell the difference (pressure) after car idled down in the outer exhaust pipe (meaning it's flap/valve defaulted to open).. Did the other side then covered & taped up connectors. Your car looks just like mine, enjoy. Ep

 

So i plugged the exhaust valves back in today.

I reset the ECU, and immediately noticed the sound is not only louder, but improved at mid range/high RPMs and there are more cracks/pops during downshifts. I believe having the exhaust valves open all the time caused the computer to dial something back. For all you gents who unplugged the valves for a while, try it with the valves plugged back in. You'll notice a difference for sure (caveat only above 3k rpm. Below 3k RPM it sounds completely muffled)

unplugged - sounds better at low rpm, more rumble, deeper. but lose the frequencies of high RPM operation. Plus it seems you get significantly less crackles and pops
plugged - sounds like almost nothing at low rpm (sub 3k rpm) but then its an huge audible increase past 3k rpm and it sounds like cams are changing over. Almost has this exotic racing quality to it as it rushes to redline.

 

How do you reset ECU ?

 

Tech stream software through obd2 port

https://static.nhtsa.gov/odi/tsbs/20...64328-9999.pdf

 

My dad just bought a lc500 and I’ve been trying to convince him to give this a try but he’s worried about voiding his warranty or it leading to negative side. Are there any downsides to disconnecting the wires and leaving the valves open?

 

To me, i could be wrong but there is only one downside is that your exhaust cover will get some black smoke on the bottom from time to time. No big deal, just clean them up with a mild degreaser and you good to go ! This aint no lambo so no need to worry to fk anything up. Enjoy

 

okay so i believe i figured it out. i think while i had the exhaust valves unplugged, they were actually closed. All you guys who unplugged your exhaust valves, try and replug them and see if you notice an HUGE audible difference.

It could be that when you have the valves unplugged they default to closed. Or.... they were open when you first unplug, but eventually that valve closes due to pressures from the exhaust gasses

 

I was thinking to do this but i gotta be fast ! Jack up the car on stands ! Lay down and get ready, one person start the car, as soon as it starts ima unplug both side and see if anything diff !

 

I havent looked into the tail pipe, but i recall the old days we used to prop the valves open with a golf T.

 

do u seal the connectors on the harnesses AND the port attached to the exhaust ? Or just the harnesses

 

There is an OEM plug from Toyota that close both ends properly. It works more like a cover. I bought it from https://www.rakuten.co.jp last year but I couldn’t find it anymore. I still didn’t install it so I will search for it and followup with a picture once I find it. Hopefully your local Toyota delaer can recognize it and get you two sets. There is no part# on the item i got.

 

Hey fellas new LC owner here, not so new Lexus enthusiast. I joined CL over 20 years ago with my SC, which I still rock to this day.

So I was studying the wiring diagrams for the exhaust valves thinking there has to be a better way than having loose plugs under the car that can get wet, get too hot, or just plain corrode from being exposed.

And sure enough, there's a single fuse that runs the exhaust valve ECU's and the valves themselves. If you just pull that, it's a much cleaner way of disabling the valves. And a lot easier to boot, just pull a fuse in the trunk.

Has anyone ever done this before?

Fuse: EFI No. 5, 15 Amp, Color: Blue
Location: Under trunk floor

This will set 2 codes, one for each valve, just like unplugging the valves does. However they do not illuminate the MIL. So no lights on the dash. 30-second mod. Replace the fuse and you're back to stock.

And if you're so inclined, you can put a switch across the fuse pins and toggle between stock and disabled (either open or closed - would depend whatever state they are in when you toggle it).






Have fun!

 

Interesting and thank you! I think members have reported sometimes the valves close back down on their own or were never open when they pulled the connectors in the first place. How does one ensure valves are open at the time the fuse is pulled so that they stay open?

 

I found it really easy and hassle free to unplug the connectors in the trunk rather than worry about having to tie and waterproof the ones under the car. Fuse method would be a good option as well, keep us posted if any lights appear after a while!

 

Been a few weeks, all good!

Pull the fuse when the ignition is off and they will stay open. They will not close again as they have no power to the valves nor ECU's. They are dead.