Which Idle Valve?

[madspikes 41 1 Cars]

I'm still having issues with my two wire bosch idle valve... Its not very smooth and the force of the air is opening the valve fully when it gets so far open! This means I end up with valve closed (nearly closed) or valve fully open, which isnt any use.

 

I'm just wondering what other idle control valves people are using? I have thought about using the standard SAD, but thats not controllable. I'd like something at least I can turn on (open) and off (close), and ideally something in between!

 

With the supercharger I dont need that much of an opening, a couple to three turns on the idle screw is about max change required.

 

I liked the two wire open initally because it would be simple to use, a different voltage equaling different opening with non of this stepper motor nonsense, but I guess now that is where I'm heading!

 

 

Suggestions please!

 

 

mad.

[Cameron 16]

You're gonna have to be more specific, what engine management are you using?

 

I'm using a Rover K-series IACV with my Emerald. A stepper motor valve is by far the most accurate and reliable method, but only if your ECU supports it.

Edited November 10, 2009 by Cameron

[madspikes 41 1 Cars]

Sorry, yes I'm using a Megasquirt One.

[Tom Fenton 1,524]

I've also struggled with the 2 wire valve and gave up. However I plan to revisit it this winter, and I have had some restrictors made to reduce the size of the hole into the valve down to 6mm. If you think of the SAD, this only has a small hole even when it is fully open.

[madspikes 41 1 Cars]

If I put the OE SAD on, I get a ~2k cold idle! I did think of making a restictor, a penny with a hole in it!

 

I'm thinking of a stepper motor type, using the MS to control it via my own electronics. I did think would 106 (or I think they are 106) plunger type be made to fit the GTi throttle body?

[Tom Fenton 1,524]

As I say, I've not tried yet. But hopefully the restrictor will help matters as it will make any increment to the PWM have less of an impact. I found on mine that it would alter the PWM to try and raise the revs if the engine was too slow, but then it would flare up, close, and then stall as it was driving all the way shut as it had revved to 3k rpm or so.

I hope with the restrictor this will control how much it flares so the ECU can "catch" the engine as the revs drop.

[madspikes 41 1 Cars]

Any pictures of that rover valve? Or suggestions on a donor?

 

Mad.

[Cameron 16]

Somewhere in my works thread I think.. I'll dig it out for you tomorrow.

[Cameron 16]

Some pics for you, not the best but you get the idea. The Rover ICV is basically the same as a GTi6 one, but the housing is slightly different. You'll have to have a trek down the scrap yard to see really.

 

 

[madspikes 41 1 Cars]

Thanks, gives me a rough idea what I'm looking for!

[paulsupervts84 0]

use a bosch ICV Off a 3 series bmw there a 2 pin

[Tom Fenton 1,524]

They are not a stepper motor though. They are more or less the same as the Mi16 PWM idle valve. That will not control.

[paulsupervts84 0]

i know saxo have a steeper motor for the idle control vavle that many work

[Baz 421]

i know saxo have a steeper motor for the idle control vavle that many work

 

I doubt it.

[madspikes 41 1 Cars]

You talking about one of these?

 

 

I did think about trying to modify a throttle body to use on of above, but thats further down the list.

 

Mad.

[welshpug 1,621]

that's what many 16v XU's and some TU engines use

 

they are 4 wire, not sure if they would be of any use though, I remember Cameron having issues and going for a different one from a Rover as he mentioned earlier. may have been compatibility issues with his ECU.

[madspikes 41 1 Cars]

Web Link

 

If I bought one of these puppies it would solve my problems, ok bar building control circuit as the G60 is also a supercharger!

 

 

Working with the ecu isnt an issue because none bar the PWM valve would with my ecu, and I dont see that type working for me. So going to have an intermediate circuit using a PIC to take the PWM signal from the ECU, to then control the stepper motor. Simples... maybe...

 

 

Mad.

[welshpug 1,621]

is it 3 wire? looks like what the 2.0 Mi16 uses.

[Cameron 16]

Stepper motor IACV's are 4 or 5 wires I think. I had issues when I tried a 4 wire (GTi6 one) as the Emerald software needed a 5 wire.. you may be able to use 4 wire IACV's on a different ECU.

[petert 549]

I've been building a 205 Mi16 using the new Haltech Platinum Sport 1000 ECU and the standard 2 wire stepper motor. I measured a standard Mi16 and it operates at 100Hz. So I've set it that. It works fine when cold (30% duty cycle) but stops sometime on the way to warm (14%). So I need to adjust the warm setting duty cycle, which I'll do tomorrow. Hope that helps as bit. Hopefully I'll report back with working screen shot of the settings.

[madspikes 41 1 Cars]

I've played with the wire valve, and with out the engine running its fine. I've also played with with it connected to the car but not to the air system, and thats fine. The problems seems to come when I'm forcing air past it! The valve just gives up and opens fully due to the air pressure. Being a supercharger... as the valve opens that increases the engine rpm which increases the air flow past the valve forcing the valve open more which increases rpm more etc... You end up with a fully open valve and a screaming engine even with no voltage to it, the only way to stop is to turn the ignition off.

 

Mad.

[Tom Fenton 1,524]

Can you not take your idle air from before the supercharger?

[madspikes 41 1 Cars]

I did have that thought, but not sure how well sealed the idle valves, especially when confronted with positive air pressure, on the side where -ve pressure is expected....

 

Plus I'm not 100% sold on that type of valve anyway! The pair I've got dont really seem to very constant on how much they open in relation to the voltage applied.

 

mad.

[Tom Fenton 1,524]

I'd agree on that, I've tried with the same valve and not got far. The annoying thing is that they are used on the 405 Mi16 and loads of other OE applications and work perfectly! My old 405Mi16 would idle at 1100rpm cold, 900rpm hot, steady as a rock.

[EdCherry 34 1 Cars]

What do charged engines use as idle valve's. Might be worth looking at jag engines and taking inspiration from their setups.