Idle control. Further assistance.

[RedMist]

I cant use the stock ST205 TB idle control and wondered if there was another Toyota vehicle that bled air via an idle control valve that wasn't attached to the TB or if there was another way of maintaining idle without cracking the throttles (I want as much engine braking as possible)

[postfach]

1UZ and 1JZ (and probably other engines) both have idle control valves mounted on the intake plenum. I assume thats what you mean by not on the TB?

[matt dunn]

The 20V 4age's had a 3 wire ISC valve that is remote mounted.
It bolts to the head just under the ITB's.
You may remember it,
or even have one among your bits and pieces.

I have a few if you get stuck.

Matt

[RedMist]

The 20V 4age's had a 3 wire ISC valve that is remote mounted.
It bolts to the head just under the ITB's.
You may remember it,
or even have one among your bits and pieces.

I have a few if you get stuck.

Matt

The older LEM's were pretty much useless at idle control. As such I never used them! But yes, I do remember. I'll have to search my small remaining 20 valve spares. Do you use one Matt? Just wondered if they take boost pressure or leak.

[matt dunn]

Do you use one Matt? Just wondered if they take boost pressure or leak.

Nah, I had a LEMV# originally and never bothered with it either,

and to me it would just be weight and complications that I dont need,
as I too want maximum engine braking,
which is why my car just idles at 600 rpm hot,
and wont even start or run with no throttle cold.


I have no idea if they would leak under boost?
maybe see how the GZE ones are done as they are same 3 wire
assembly on a different mount. Not sure if they separate from
the throttle body or not?

[gmacrae]

There's no need for an iacv, esp in a racecar. Remove it and make your own idle control valve of some sort (ball valve works good on my silvertop). Starts perfect cold and idles at 600ish, 900 warm, could go lower no prob.

[flygt4]

depends on the engine, how many cylinders , the size of the injectors and the tune etc
my tune is pretty good, but with no idle control from a cold start it gradually gets rougher and rougher until it stalls after 15-20seconds. idles perfectly at 900rpm once warm though.

[RedMist]

I simply want idle control as it should close during running RPM/boost. IE when you come off throttle there is no leaks and considerably better engine braking... They cant bleed throughout the RPM range unless they have a check valve in place to stop leaking boost pressure? I think?

In addition I want to be able to flick a switch to enable antilag, which in turn will open a second valve to bleed additional boosted-air into the manifold. As the ST205 bleeds non boosted air I suspect the ISC's are prone to failure on too greater pressure differential. As such a stepper ISC may not be the way to go for this second valve. I suppose I could use a solinoid to shift the throttle stop and crack the throttle.

[RedMist]

There's no need for an iacv, esp in a racecar. Remove it and make your own idle control valve of some sort (ball valve works good on my silvertop). Starts perfect cold and idles at 600ish, 900 warm, could go lower no prob.

I need it to be open on idle and closed on anything above idle to maximise engine braking.
I never ran ISC on my NA 4age's with LEM's. I just manually cracked the throttle for the first 5 minutes of warmup until it took on a very lopy 800rpm idle. I too didnt want the complexity or potential component failure. However this car is a little different.

In a scandanavian flick I don't generally brake. I simply turn slightly in the wrong direction and engine brake. I let the rear end break away and then turn into the corner. With this car being mid engined it will take more to break away the rear end and when it does I need the engine braking to be linea (as a middie will change ends very quickly indeed).
I wonder if I'm expecting too much. I wonder that with throttle and ISC valves close that it will simply create enough vacume to damage something.

[gmacrae]

Ahaa right i see... like matt said, the 20v ones are remote mount, pipe in pipe out kinda thing, could be used in anything i guess. Dont know if they're a stepper motor or not? dunno what the alternative is. They look nothing like the mitsy stepper motors i was playing with a while back (thank god).

Can you make an external idle valve of some sort (ball valve etc) with a solenoid inline that the link closes above say 1000 rpm?

Are you worried about an IACV leaking under boost? Cant you just take its air supply post-compressor? so under boost, pressure either side of it is more equal?

[RedMist]

Are you worried about an IACV leaking under boost? Cant you just take its air supply post-compressor? so under boost, pressure either side of it is more equal?

I wondered about that. Then I thought there must be a reason for the factory idle control to be taken pre compressor. Perhaps boost fluctuations make it hard to control the flow? Or perhaps when you close the throttle with a vacume one side and boost the other, it leaks.

[RedMist]

Need further assistance if possible. Idle control will be a simple valve with a non return valve inline so that boost can't blow past it.

HOWEVER...
I need additional air to enter the plenum when antilag is enabled. As such need another bleed point with some way of enabling the valve with a 12 volt signal. I thought about using a boost controller (such as the MAC valve Link use).. but they are expensive and I doubt they will flow anywhere near enough air. Arent they PWM as well?

[sergei]

back to original post, you say you cannot use stock ST205 ICSV, why?
As far as I know the construction and functionality is similar to 20V one...
If everything fails you could get a generic BOSCH Idle control valve, which could be PWM or crude ON/OFF sort of thing. These things are humongous and can flow a lot.

[RedMist]

back to original post, you say you cannot use stock ST205 ICSV, why?
As far as I know the construction and functionality is similar to 20V one...
If everything fails you could get a generic BOSCH Idle control valve, which could be PWM or crude ON/OFF sort of thing. These things are humongous and can flow a lot.

The custom dual plenum intake is tube. It doesnt currently have the lower "knotches" for the IAC, and it wouldnt be easy to construct without a tonne of work.
But of more import, I in pure stupidity, threw them out.

Who the heck supplies Bosch in NZ? Ripco dont supply anymore and the Bosch site doesnt work for a dealer list.
I need a Bosch IAT, Bosch fuel filters and now ICSV's !

Can you straight switch a PWM IAT without it fusing? Or are you saying that Bosch have a simple one setting on / off IAT (for something like AC idle up)?

[matt dunn]

We do bosch thru work if you want IAT sensors and stuff.
Do you have part numbers or want options?

[RedMist]

We do bosch thru work if you want IAT sensors and stuff.
Do you have part numbers or want options?

Cheers Matt, have emailed you.

[MasCam]

reading through this it makes me wonder if you just can't use a solenoid valve with a frequency switch for the idle control with a ball valve to set it up.

Or ignore the idle control valve as others have and just use a switched solenoid for cold startup and set it to just run on no throttle.

You could run the frequency switch through a relay for two circuits to two solenoids one of which is for normal idle control and the other to another one that opens when running the antilag supplying more air at that time (I am presuming that you will have some sort of electrical supply activating the Anti-lag, or can supply one??)

Chris

[RedMist]

I'm using a Link G3Plus which requires a DI switch to enable antilag. My thoughts were to also use this switch to cock the throttles to enable more antilag air. Otherwise I'll constantly have to run the engine with an idle of about 2k and obvious issues in regards to engine braking.

[MasCam]

Yeah was just thinking that it may be easier and more reliable to use a separate air feed with a solenoid valve in it than making a setup to cock the throttles??

Also I can't quite get my head around how you run antilag and get good engine braking, wouldn't you have to inject air into the exhaust manifold for that??

[RedMist]

Yeah was just thinking that it may be easier and more reliable to use a separate air feed with a solenoid valve in it than making a setup to cock the throttles??

Also I can't quite get my head around how you run antilag and get good engine braking, wouldn't you have to inject air into the exhaust manifold for that??

Mutually exclusive. I cant have antilag and good engine braking. Which means if I do require antilag my driving style is going to have to radically change.