Idle control.

[DaveEFI]

This sort of comes out from the bit about the Camens ECU.

At the moment, I'm using all of the original Lucas idle control on my SD1 fitted with a MegaSquirt.

Cold start fast idle uses a simple extra air valve which is basically controlled by coolant temperature and an electric accelerator coil.

Normal idle has two electrically controlled extra valves to compensate for the load when you engage drive and or use the AC - both stand alone, not controlled by the ECU.

I'd like to go for closed loop idle control. Have a hotwire stepper motor (not yet fitted) which MS can control - but the Camens blurb reckon a PWM controlled 2 wire valve is more reliable and easier to programme.

Anyone got experience of both and care to comment?

[Quagmire]

The Bosch PWM valve where the inlet and outlet are at 90 degrees to each other is the way most of the Landrover chappies do it. Have a google around on LR4x4, it must have been covered a few times on there.

Part number 0258017025 or such?

I have had one sat on the shelf for years now - I was using the flapper style one previously then in a fit of enthusiasm removed it to fit the new PWM one only to get sidetracked and ended up plumbing the LR back together without anything. I have not got round to even reinstating the old one!

TBH as you have MS2 I'd use the 4 wire stepper as its probably neater to install if you have the later plenum with it all bolted to the back?

*edit - Thinking about it, probably the only reason that the LR crowd use the PWM pretty much exclusively is that most are on MS1, which precludes anything else.

[DaveEFI]

I've got all the bits required to convert to stepper motor - and the MS2 already has the chip on board to drive this. I've had it working on the bench, using a spare MS2. And agree it would look fine.

However, I'm confident I could get a Bosch valve installation to look ok too, except perhaps to a purist.

What I've no real experience of is PWM control of this sort of valve - I assume this can give variable opening, so control the speed exactly?

Is it at least as fast reacting as a stepper motor - or better?

I've also read of several having problems with the actual stepper motors - I'm assuming the Bosch valve is of a simpler construction so hopefully more reliable?

[stevieturbo]

Ultimately how well it works will largely come down to the ecu itself ( and the person using it )

Will a simple solenoid/PWM valve be quicker ?....depends on the valve, and of course how quick you need it to be, and how much actual control it offers.
A huge valve might see very fast engine speed changes per duty, but be too impractical for that very same reason.
A small valve might be a little slower in that respect, but far easier to control.

By large/small I mean the amount of air it can actually flow, not physical size.

Is a stepper motor more complicated ? of course it is...but will it's operation be more complicated ? again, that comes down to the ecu being used.

Does idle control need to be super fast ? Not for the most part, so either should be fine.

So really....just use whatever your ecu allows and physically fits the easiest. It'll be trial and error to get it working nicely anyway.
And if you need idle control to operate faster, use timing first, and then an air bypass.