Ok, so bear with me. This is actually happening on my Lexus GS400, but I've detected it to a lesser degree on our UZJ100 as well. Both have well over 200k miles and run flawless. Since they're both basically the same engine I figured you mudders will be a load more help than ClubLexus...
So here's what's up: Under part throttle (say 40%), right at 3300rpm, every time, there's a sudden surge of power that kicks pretty hard. Like, it'll push you back in the seat and if the roads are wet the tires will get unsettled. It's much less noticeable on the Land Cruiser, but still detectable if you're paying attention.
It's not a gradual rise in power output. It's a very noticeable "kick."
Happens whether or not the VSC is enabled.
Happens regardless of what gear I'm in.
It's not the ACIS. This was happening both with and without the ACIS system functioning.
I don't think it's the VVTi. The Techstream diagnostics for VVTi says everything is working fine, and the car idles normally.
It became more intense after I swapped the Tundra intake onto my engine.
It doesn't sound like the computer is manipulating the throttle--my Lexus makes a ton of induction noise so it's very easy to tell what the throttle is up to (like when it closes down during gear changes).
I recorded the "kick" three times in Techstream, but the graphs don't update fast enough to show what's happening. By the time it takes another "snapshot" the event has already passed.
Unless I'm missing something, I believe the engine is pulling timing until 3300rpm. But why would it do that? Would a vacuum leak cause the computer to run in "safety" maps in the lower RPMs? Unstable detonation wouldn't lead to consistent predictable timing retardation, would it?
Last I checked, the valve and head were extremely clean, so I doubt carbon build up is the problem.
I'm going to try and find another OBD device that'll update fast enough to see what's happening, but I don't have a lot of hope.
This should be a fun one for y'all to muse over. Thanks in advance for any knowledge or suggestions that'll help me figure this out!
So here's what's up: Under part throttle (say 40%), right at 3300rpm, every time, there's a sudden surge of power that kicks pretty hard. Like, it'll push you back in the seat and if the roads are wet the tires will get unsettled. It's much less noticeable on the Land Cruiser, but still detectable if you're paying attention.
It's not a gradual rise in power output. It's a very noticeable "kick."
Happens whether or not the VSC is enabled.
Happens regardless of what gear I'm in.
It's not the ACIS. This was happening both with and without the ACIS system functioning.
I don't think it's the VVTi. The Techstream diagnostics for VVTi says everything is working fine, and the car idles normally.
It became more intense after I swapped the Tundra intake onto my engine.
It doesn't sound like the computer is manipulating the throttle--my Lexus makes a ton of induction noise so it's very easy to tell what the throttle is up to (like when it closes down during gear changes).
I recorded the "kick" three times in Techstream, but the graphs don't update fast enough to show what's happening. By the time it takes another "snapshot" the event has already passed.
Unless I'm missing something, I believe the engine is pulling timing until 3300rpm. But why would it do that? Would a vacuum leak cause the computer to run in "safety" maps in the lower RPMs? Unstable detonation wouldn't lead to consistent predictable timing retardation, would it?
Last I checked, the valve and head were extremely clean, so I doubt carbon build up is the problem.
I'm going to try and find another OBD device that'll update fast enough to see what's happening, but I don't have a lot of hope.
This should be a fun one for y'all to muse over. Thanks in advance for any knowledge or suggestions that'll help me figure this out!
