VVTi disconnected?

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JustenGT8

New Member
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2,433
Location
Canberra, Australia
Has anyone (for whatever reason) run their 1UZ or 3UZ VVTi with the VVTi disconnected? I am curious if the ECU will even let the car start and if so how did it run?

My built VVTi with aftermarket ECU is behaving badly....i'm trying to determine if it is expected that it would sound as rattly as it does with the VVTi unpowered, or if there's another problem entirely.
 

gloverman

Well-Known Member
Messages
3,025
Location
Hamilton. New Zealand
They start fine on stock ECU with VVti disconnected. They also start fine on aftermarket with VVti disconnected. When I tune VVti systems on the dyno I turn it off , do a run and plot the graph. Then overlay runs with around 5 degrees added each time to work out a preferred VVti plot. The actuators in other Toyota's do give a little trouble. I have changed plenty of VVt 20 valve 4age units and quite a few VVti 3Sge beams altezza ones. They have all had a rattle.
On stock piston clearance it is fine to flick the solenoid onto full advance without anything touching.
 

JustenGT8

New Member
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2,433
Location
Canberra, Australia
It's more than a rattle in this case....a head full of smurfs with hammers is how I have described it elsewhere....it makes no sense if this was a runner as sold? Even if it developed as issue this noise is so loud you would shut the car down instantly...it's not a mild " oh what's that?"... More a OMG WTF is that!!!
 

gloverman

Well-Known Member
Messages
3,025
Location
Hamilton. New Zealand
I had one of those recently on an early engine which I wired up. First start up with a rat-a-tat-tat-tat just like big ends. Instant shut down and oil check. The owners mate was a engine reconditioner and he could hear it across the garage over the phone.
With a bit of checking I traced it to the LH front of the engine. Turned out the lower plastic cambelt cover was sitting on the inside of the locating tag which allowed the trigger tag on the cambelt sprocket to smack it each revolution. Few minutes with the spanners and it was fixed before the reconditioner got there.

How long has it been sitting? What about sticky valve or popped collet allowing it to touch a piston?
 

JustenGT8

New Member
Messages
2,433
Location
Canberra, Australia
It's been sitting a while, although I did turn it over gently by hand on occasion. Oil pressure is very healthy.

Multiple knocks in both heads. You can feel them with your hand on the cam cover so pretty solid. Piston tops I have Checked all look fine.

I'll whip the cam covers off, all plugs out but there's no noise on crank so it's not likely anything is touching that shouldn't be? It's just weird?
 
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