7MGTE ISCV on standalone engine management

[kemicalx]

Just a quick couple of Q's

On my 7MGTE I will be running standalone engine management and as such won't be able to control the stock ISCV without using up 3 of the 4 aux. outputs on the ECU, I've been told the 4AGE ISCV is a simple 2 pin solenoid, and thus will only take one aux output.

Just wondering if anyone could confirm/deny this? Also some pictures would be fantastic, are they only found on particular 4A's? And how much am i looking at spending on one?


Thanks guys,
Ash.

Edit -

I found this info on mkIIItech, quite useful

The toyota IAC is a 6 pole design stepper. Usually labled S1-S2-S3-S4 for the switching ground and B1-B2 for the 12+ vdc. This automatically makes the stepper motor a unipolar designed stepper motor. What this means is that the stepper motor recieves the the energy in only one direction... B1-> S1, B2 -> S2, B1 -> S3

To open the pintle the sequence would be

S4 B2
S3 B1
S2 B2
S1 B1
S4 B2.. x 125

this sequence is controlled by the TCCS. To close the pintle it would be the exact reverse.

S1 B1
S2 B2
S3 B1
S4 B2
S1 B1.. x125

The nice thing about unipolar stepper motors regardless of how many poles it has is that you can make them into a bipolar stepper motor (very important for stand alone ecu's especially if they can control a GM type 4 wire idle motor). Bipolar stepper motors use current flow in opposite directions to open and close the stepper motors. So to use the Toyota IAC as a bipolar stpeer motor you connect the 4 wires from what ever standalone you are using and connect them to pins S1 and S3 for one leg and ping S2 & S4 for the other leg.

what happens now is that to open the pintle, the logic becomes and current flows from

S1 S2
S3 S4
S1 S2
or in other words you are energizing two coil pairs at the same time.

To close (pay attention to the current flow here as this is what make the 6 pole steppers work with only 4 wires connected)

S2 S1
S4 S3
S2 S1 .....

the current flow is REVERSED of what it was during the opening sequence. Hence the name bipolar.

According to all the research I did. The Toyota IAC shows 125 steps but in reality it has close to 255 steps. Also it is quick and if the standalone has adjustments it must be set to at least .25 seconds per step or 4 steps a second.

Just thought i update this with some specifics.

Electromotive and any other ECU that supports a GM stepper or Ford Stepper has to be run in bipolar mode (Tec3/Tec3r, Big stuff, F.A.S.T) which is S1-s3, S2-s4.

Motec, Wolf V500, Autoronic support the stock stepper. Motec Specific wise

Aux5 => S1
Aux6 => S2
Aux7 => S3
Aux8 => S4

B1 and B2 to fused battery Positive.

[kemicalx]

b-b-b-bump

[BeRad]

the iscv should only use one output, why should it use 3, mine only uses 1 as does all of my mates cars, with aftermarket ecu's.

[kemicalx]

Is that on a 7mgte? the 7m one is a 6 pin solenoid

[BeRad]

no its not on a 7mgte sorry, do you know what the 6pins do?.... maybe a few arent used with an aftermarket ecu.

theres several sensors on my 3rz, that dont use all the stock pins with an aftermarket ecu.

[kemicalx]

Mmm I don't know exactly to be honest, but i think it is some kind of stepper motor

Ideally i want some kind of simple solenoid that will open and close, that can be operated via pulse width modulation, will be noisy and probably not the most effective way of controlling idle, but i could set it up easily enough with my ems.

[Hen]

Yes, that's a stepper motor idle control. Only 4 pins are needed to control them (2 are 12V). However only some ECUs can control them.

Apparently an XF uses a simple PWM solenoid for idle speed control. I can't comment on the 4AGE.

Don't worry about the PWM being noisy. Just up the frequency til you can't hear it.

Hen

[kemicalx]

Cheers hen, I'll have to check out the XF one then, won't be too hard to find

[kemicalx]

updated the original post, looks like i may get away with using the stock ISCV afterall, but just use up two of my outputs to energize two of the stepper motor poles.. I'm still going to hunt down an XF one as running pulse width modulation will be easier for me. But i thought I'd throw up the info anyway

[thechuckster]

XF (6 cyl ZL fairlane as well) have PWM-driven aux air valves - just 1-wire (well, 2 actually but one is a supply) is needed to drive these guys.

There are also some bosch units that have 3 wires (part 0280 140 505) that work the same way but use an extra wire:
http://megasquirt.sourceforge.net/ex...osch-valve.JPG

[JustCallMeOrlando]

XF Falcon is as described. A 20v 4AGE has a PWM ISCV as well.

Everyone above is correct, to control a stepper ISCV requires 4 outputs, your 7M one is similar to my 1G one which consumes 4 of the outputs on my Adaptronic.