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Zetec Megasquirt IAC
Bacon2002 - 8/7/07 at 07:12 PM

Hi,
I am building a megasquirt to run a 2.0l (blacktop) Zetec.
Currently I am at the stage where I need to choose what type of Idle Air Control to use.
I am not entirely clear on this as I bought the engine for a Locost project and I do not yet have any experience of using an IAC'er or a megasquirt.
Has anyone who has already done this got any advice they could share.
The megasquirt seems straight forward to build and all tests OK so far.
I suspect I will need to use whatever controller is used on the standard engine which looks like it could be the Idle Speed Control Valve? (I do not currently have one of these).
Any advice would be appreciated, according to the Haynes manual the Idle Speed Control Valve would appear to be located near the Air Mass Meter and therefore I assume forms part of the air intake.
I intend on using a bespoke plenum chamber and air filter and am a little confused as to how to get around this.
Many thanks,
David

scottc - 8/7/07 at 08:03 PM

Theres a Bosch item, thats from the old CIS setup thats completely independant. You basically give it 12v and it warms itself up and closes an air valve.

If you have a look in the megamanual its the last IAC.

muzchap - 8/7/07 at 08:31 PM

Hi Bacon,

Ditch the ford plenum! Seriously! You have an excellent black top engine - fit some bike throttle bodies and use the megasquirt and you'll make around 160hp with a decent zorst.

Get some ARP rod bolts and then you can rev round to about 7500.

I have a decent base map for the MS if you want - mines making 160hp and 140lbft torque.

Or - I have heard of people using the Rover Inlet manifolds (silver ones - not plastic) and achieving similar results - if you did want to use Idle control valve's etc

Cheers,

M

TangoMan - 8/7/07 at 09:21 PM

I don't use an IAC valve and have a good steady idle. It drops temporarily when the fans cuts in but recovers OK.

It does need to bit of throttle for a minute after cold start until it warms up a bit. I thought about using an IAC valve for this as I have one off the mondeo manifold. I would just plumb it into the spare air nozzles on my TB's for ease.

Bacon2002 - 8/7/07 at 09:34 PM

Hi,
Does anyone know if the standard Ford Idle Speed Control Valve is a stepper motor type or a solenoid type?
Thanks,
David

Fatboy Dave - 8/7/07 at 10:17 PM

quote:
Or - I have heard of people using the Rover Inlet manifolds (silver ones - not plastic) and achieving similar results - if you did want to use Idle control valve's etc

Cheers,

M


The black Rover T series manifold (the silver one is M series) is ali, not plastic. The M series plenum is quite a rare beast now, as it was only fitted in any numbers to the mk1 Rover 820.

I've used a quarter turn washing machine valve fed into the plenum with good results before. Bit basic and brutal, but hey, it works

BKLOCO - 9/7/07 at 04:50 PM

quote:
Originally posted by Bacon2002
Hi,
Does anyone know if the standard Ford Idle Speed Control Valve is a stepper motor type or a solenoid type?
Thanks,
David



It's actually neither.

It is a PWM type. (pulse width modulated)

Sounds like a moose on heat when installed in anything but the standard Ford mainfold.

VW use a similar system but the valve is a neater design.

Hope this helps.

Bacon2002 - 9/7/07 at 09:12 PM

Thanks BKLOCO,

I understand, just like a servo.

I'll use the PWM option on the Megasquirt.

Cheers,

David

martyn_16v - 10/7/07 at 05:04 PM

You may find you need to upgrade the FIdle transistor on the MS board if you have a v2.2, the VW PWM valves have been known to kill the diddy 2N2222A, the ford valve might draw similar current.