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Discussion Starter #1 (Edited)
Hey guys!

Got an Aristo 3 months ago (Jesus Christ I'm loving that car) and during the aprox. 2500kms I've done in it during that time, something weird has occured 3 times (most recently today". The car, seemingly out of nowhere starts to vibrate more, and the idle gets a bit weird (like a mildly cammed jz)? After some time the car would make an elephant like sound (really not sure how to explain it haha) for a second or two and the vibration goes away again. Haven't noticed any pattern as to when it happens.

Not really sure what this could be hence I'm coming here for help. The belt has been changed around 7000km ago at a Lexus dealership before I bought the car. Looking at it, it seems as it may be just a bit out of line, but not really sure if it's that or just that the white text on the belt makes it seem like it wobbles. May it be the water pump?
 

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A video definitely would help but it sounds like you're getting a misfire which is then fixed by the "elephant like sound".

Is the car on stock twins or is it a single?
 

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Discussion Starter #4
Stock twins VVT-i, problem with making a video is that it happens randomly and happened only 3 times. It is for a couple secs and then goes away.
 

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Is it happening when you're cruising along or when you're at full throttle?

It sounds like an issue I had with my stock twins, where one of the VSVs went bad and so my 2nd turbo would intermittently not come on at wide open throttle. At cruise though there were no signs, as I was in vacuum, or seeing <7psi on the first turbo. Have you checked all your vacuum hoses and checked the VSVs?
 

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Discussion Starter #6
I am running my turbos in TTC. 1st time it happened while idling standing parked, and the 2 other times while juat cruising along.
 

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Discussion Starter #7
But I think my vsvs might be bad as I can hear the first turbo start spooling at like 2300-2500rpm
 

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OK a couple more things to diagnose here...

1. How have you performed the TTC mod? Re-plumbing the VSVs (the quick way) or the permanent way?
2. You say the first turbo starts spooling at 2300-2500rpm...is that when the turbos are in TTC or sequential?
 

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The 5 minute TTC mod requires you to do a full throttle run to "fill up" the pressure tank. Once the pressure tank is "filled up" TTC mode will work fine. I had to do the same on my Aristo and both turbo's didn't come online, hard, until 4k rpm. Also if I'm not mistaken the VSVs are still in play, but working in reverse, when doing the 5 minute TTC mod.

Also consider boost problems can be related to not just bad VSVs but also a boost leak or a vacuum leak...and worst of all bad turbos.

Here's an article talking about each VSV in the 2JZ-GTE Sequential system which should give you a good idea of what to check.

 

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Discussion Starter #12 (Edited)
I know that. Been running the TTC mod for the last 1k kms or so.

Hmm, will look for boost leaks and take the intercooler pipe to look for oil spillage. Car doesn't seem to use much oil tho.

I think my afrs are a tad bit rich for idle? It's idling at 14.-14.4

Edit: WOT AFR is 10.3-10.6 (so defo rich). 02 sensor probably?
 

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Discussion Starter #14
Alright, will do that :). Should probably also mention I run a walbro 255lph, but that shouldn't make a difference as I still have stock injectors, or?
 

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Do you have it hard wired to the battery with a relay to turn on or are you using the stock fuel pump ECU?

If the stock fuel pump ECU, I know the pump struggles at lower voltages and at full voltage the fuel pump ECU doesn't provide enough voltage either, and can cause a bit of an issue when transitioning between the 1st and 2nd turbo.

Regarding the voltage deficiencies of the stock fuel pump ECU, and the pump struggling at low voltages, I discovered when I ran my S366, whilst trying to max out my stock 440cc injectors. I then proceeded to hard wire a relay with 12v direct from the battery, using the fuel pump ECU as trigger, and got another 1psi of boost without leaning out (AFRs were 10.8 at 14psi wide open throttle after the mod).
 

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Discussion Starter #16
Hmm, not really sure as it was done but some previous owner, but I guess it's using the stock fuel pump ECU. Will check tomorrow.
 
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