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High revs but no speed increase on auto kickdown!


RedM
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Just to clarify Martin, this happens on mine when I floor it at a speed where the autobox kicks down but to very high revs - as if I'm suprising the turbos and they've not woken up (going from no boost to full on) Normal acceleration etc it's fine.

 

Exactomundo. The bit about suprising the turbos is very good. Yes, it's almost like they've spooled down and have to get going again. Normal acceleration is fine. Up though the gears with no issues and a nice hefty increase at 4k.

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Could the slipping be caused by fluid issues rather than the TC actually slipping?

 

No take it to an auto box specialist, don't waste money on new fluid, it won't fix it unless the fluid level is far too low right now, but once they slip damage is already done. How are you measuring the fluid level, step by step???

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No take it to an auto box specialist, don't waste money on new fluid, it won't fix it unless the fluid level is far too low right now, but once they slip damage is already done. How are you measuring the fluid level, step by step???

 

Do you know of any autobox specialists in the Leeds area?

 

I had the fluid replaced today at a very, VERY good rate;) and TBH it hasn't made any difference. The problem is still there when accelerating hard from 60-70 ish.

 

If you've got oil mist on the outside of the components then you've got a boost leak.

The blow off valve is recirculating so it dumps everything back into the system.

I would replace any cracked/brittle hoses and make sure all the clamps are done up tight.

 

Could a boost leak be causing the second turbo to spin up slowly?

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Do you know of any autobox specialists in the Leeds area?

 

I had the fluid replaced today at a very, VERY good rate;) and TBH it hasn't made any difference. The problem is still there when accelerating hard from 60-70 ish.

 

 

 

Could a boost leak be causing the second turbo to spin up slowly?

 

Sounds like vsv problems to me....sounds bizzare but when it happens does if feel like one of your intercooler pipes is completely blocked for a few seconds and then is suddenly released and you boost again fine?? happened to mine a few times in the past and it baffled me

 

If you had a boost leak you would know straight away and not realy build bost at al! have you noticed a drop in pressure at all?

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First verify that it is the autobox at fault and not the engine. Put it in manual mode, think of something.

 

Apart from dodgy VSVs, cracked boost hoses and such, also check those two 'accordion' looking rubber hoses (one you have already in red circle)

They are not easy to take apart, but they are known to collapse on the inside, blocking the path and giving the impression that turbo #2 is blown or something in those lines.

From the outside they look OK, but that can be deceptive because they are double-skinned.

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Firstly, I have no boost gauge so I cannot tell what the boost level is doing.

 

I get superb gear changes at every moment EXCEPT when I'm doing about 60-70 and floor it. At high speeds the box works fine too. It's just at that speed range there is an issue. Turbo two comes online as normal, manual mode is fine too.

 

But John, I will have a look at that pipe when I get time. I'm back at work until Xmas now!

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Firstly, I have no boost gauge so I cannot tell what the boost level is doing.

 

 

Invest in a boost gauge, this should be top of the list for any turbo owner

 

 

I get superb gear changes at every moment EXCEPT when I'm doing about 60-70 and floor it. At high speeds the box works fine too. It's just at that speed range there is an issue. Turbo two comes online as normal, manual mode is fine too.

 

 

 

My bet is definatly vsv then, from that speed its probably dropping 2 gears into second and the huge boost hike is causing problems with the old pipes

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That 'dropping two gears into second' sounds good. If I accelerate briskly it drop down what feels like one gear and the revs go higher but only like turning O/D off. Mashing the pedal into the carpet makes the revs skyrocket and I was still assuming this was third but with some wacky slippage.

 

Will get the VSV stuff checked but at this point I need to hold my hand up and ask

 

What does VSV mean?

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if it was slippage surely it would go right upto redline.

 

Mine does like slightly red, slam ya foot down it revs for about half a second, then goes im sure its just tubby 2 getting upto full speed.

 

VSV's are the electronically controlled switchs really, puts vacum/pressure in a certain place to work the acuators. u have 4 of them i think and they are key to the sequential setup.

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That 'dropping two gears into second' sounds good. If I accelerate briskly it drop down what feels like one gear and the revs go higher but only like turning O/D off. Mashing the pedal into the carpet makes the revs skyrocket and I was still assuming this was third but with some wacky slippage.

 

Will get the VSV stuff checked but at this point I need to hold my hand up and ask

 

What does VSV mean?

 

with overdrive on ie button engaged if will drop 2 cogs on kick down revs will skyrocket and you wil get a massive boost hit from the 2nd turbo...but only very shortly as it changes to 3rd

 

Im certainly no expert on these valves but they basically control changeovers in the sequential system >

 

there is a lot of reading if you search in the FAQ

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Ive redone your picture for you.

 

The ones ive circled in green are the VSV locations, they are a little black box with vacume hoses going to them, they also have a electrical connector attached to um.

 

Follow the vacume pipe ive outlined in blue and you will find the other 2 located in the depths (but sorta easy to get too once you remove the airbox + intercooler pipe)

 

Just check all the rubber hoses going to the VSV's for cracks, they will no doubt be brittle like mine were, so dont go pulling at them if your not replacing them yet (mine just shattered)

enginezd7.jpg

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with overdrive on ie button engaged if will drop 2 cogs on kick down revs will skyrocket and you wil get a massive boost hit from the 2nd turbo...but only very shortly as it changes to 3rd

 

Im certainly no expert on these valves but they basically control changeovers in the sequential system >

 

there is a lot of reading if you search in the FAQ

 

This is sounding more like it.

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This is sounding more like it.

 

Dont want to tempt fate by saying it but as we all know the lovely toyota mechanics over engineer most of the parts we have on our cars and the auto box is no exception, slippage at that milage is not heard of unless you have been seriously abusing it

 

a mate of mine power breaks, does burnouts, drifts in manual mode and also shifted into reverse halfway up the track at pod in his auto and its still going strong

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Without wishing to complicate things, does it happen at around 60mph Martin? Mine does exactly this and I'm convinced it's nothing to do with the TC but a dodgy VSV somewhere...... it kicks down into 2nd and revs it's arse off but crawls forward because the boost isn't being routed properly via both turbos and instead just goes back out one or the other.

 

Basically it's like Ian's entry in the FAQ, see a couple of 0.x of boost but nothing more. After a few seconds it sometimes builds up properly again but more often that not it'll take off properly if it shifts into third or I let off / reapply the gas.

 

ditto- check the boost on kick down. If its low i.e between 0. 0.3 bar then this may be you problem. If boost is low on kickdown then the car will feel slower as the revs rise. I bet this is your problem- vsv

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Right, having spoken to my regular mechanic he initially said autobox knackered straight away.

 

However, after talking over some more points in great depth he said that a boost leak might be the cause.

 

So, as he is only up the road the car is going to him for a day after Xmas. Hopefully, it'll be a VSV issue if not I think I've sourced a suitable replacement.

 

To be continued.....

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Did reverse work ok?

 

Indeed it does. This is what makes me think it isn't the box. It's absolutely fine EXCEPT when flooring it from the 60-70 mph mark.

 

Of course, what I think is fine may not actually be fine. I could be suffering all sorts with it but know no different!

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