Can anyone explain what might cause this?

When I first start it, it idles at 2k rpm then the idle drops to around 1,300.
It fluxuates like that till it warms up. Then it stops. After about 10 minutes of hard driving it begins to do this again.

And advice where to start checking?

Here is a video of how the car idles.

http://s127.photobucket.com/albums/p136 ... I_4767.flv

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Coldiron (Cold - Iron)
1992 Celica Gt4 RC Conv. St205 swap

http://www.noritoy.com

The max idle on a 205 I've seen is 1500rpm, and that's when it is very cold.

At the risk of sounding predicatable and boring, do you have any air leaks post throttle body? What about fault codes? Stock ECU?

Has the car always done this, or is it a new problem just surfaced?

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
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Turbocharging - the replacement for displacement

Car did this with the old ecu and new ecu. Both ecus are stock as far as I know.

Its done this since its run. At least since I have had everything hooked up.

I think it is vac related. I am trying to locate a vac line guide of some sort. The pdf 205 bgb is not very useful on the vac hoses.

No fault codes either.

I do not have the a/c idel vsv hooked up, but I understood that it does not affect anything unless the a/c is on.

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Coldiron (Cold - Iron)
1992 Celica Gt4 RC Conv. St205 swap

http://www.noritoy.com

Is that electrically not connected or vac line not connected? Electrically I doubt it would make any difference, but I would connect the vac lines.

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement

I will hook it up then to see if it changes anything.

Any other suggestions? Whats max boost on these things? Mine tops out at 10psi since code 54 is gone.
Is there a boost limit on 1st gear?

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Coldiron (Cold - Iron)
1992 Celica Gt4 RC Conv. St205 swap

http://www.noritoy.com

When I did an engine swap on my red one it had idle problems. Turned out to be the metal gasket from behind the throttle body had dropped down onto the engine and was bridging different the top of the head and the throttle body. Im not sayin that thats it, but it could be a similiar electrical problem with parts being bridged that arent meant to be.

Maybe the 2 vac lines that go down to the power steering pump? Leaking DV?


With all the 205 bits and bobs ~17psi


I would've said that is a little low for a stock 205.


Yes. This is achieved by not activating the TVSV gizmo.

If you fit a boost controller then it is popular opinion that you should disable the TVSV to achieve a reliable repeatable boost pressure level in all gears.

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement

Are there any proper online directions for installing an EBC in a st205?

I am going to try and finish up this vac stuff by next weeked, then take it in to install my st205 lsd.

BTW: Do I need to order any extra bit from toyota to install torsen guts into a open dif housing of a 185?

thanks again,
JC

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Coldiron (Cold - Iron)
1992 Celica Gt4 RC Conv. St205 swap

http://www.noritoy.com

Which EBC are you installing?
Have you checked the MAP sensor?

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ST205




"And God said, Let the earth bring forth grass, and the earth brought forth grass and the Rastafarians smoked it."

The line that went to the map sensor had a "T" in it when I got the car. What ever was T'ed in was not connected.

I was told by an mr2 guy that there should be no T and for it to go straight to the map sensor.

Could their be something missing?

I have a greddy Prof B boost controller.

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Coldiron (Cold - Iron)
1992 Celica Gt4 RC Conv. St205 swap

http://www.noritoy.com

10psi sounds like standard actuator boost (0.7bar) so I'd say the turbo VSV is disconnected

A T in the MAP sensor line sounds like either an aftermarket boost guage install or a feed to an EBC sensor - which might explain the apparently disconnected Turbo VSV

1900rpm om mine 205 when colder than -20 degree celsius

Could the turbo vsv still be disconnected in this situation:

When I had code 54 it would not boost over 5psi. Is there any other way the ecu could have something limit boost other than the turbo vsv?

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Coldiron (Cold - Iron)
1992 Celica Gt4 RC Conv. St205 swap

http://www.noritoy.com

Personally I would never use this line, or the fuel pressure regulator line to feed anything.

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Kris
95 ST205 - slept for 10 years, now waking up...
Avensis
http://www.gtfours.co.uk
_______________________________________
Turbocharging - the replacement for displacement

Have you thoroughly checked out the throttle body to a) make sure it's fully closing when throttle is off b) ensure the cable is slightly loose at idle c) the idle control screw has not fallen out?

There may also be a bung on one of the take offs on the rear of the inlet manifold (difficult to see and get to) that may have come off causing the leak.

I'm checking all these things on mine at present as I'm also having an idling problem, read 1200rpm tickover. My idle up valve is not being used (pipe to intake is blocked as it initially helped bring idle down) and my idle control screw is fully in! I just need to check the rest now

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'92 GT-Four RC - Project Rufus - something of a mover.
'05 Audi A3 3.2 V6 Quattro S Line - not bad for a daily.