Chaz
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| posted on 28/7/12 at 10:11 PM |
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Stepper IAC Vs Fast Idle IAC - experiences required
Hi, I'm at the part where I need to think about using a stepper motor IAC configuration or fast idle IAC with megasquirt.
What are your experiences of each?
I have a zetec silver top soon to be supercharged. Don't even know which IAC valve I even have on offer for me either, again any ideas?
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Chaz
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| posted on 29/7/12 at 09:34 PM |
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Bump - I'm kinda stuck here, hope someone can help
Calling all megasquirt people 
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djtom
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| posted on 30/7/12 at 07:26 PM |
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I've not tried a stepper motor valve but I did use a 3-wire Bosch IACV with my megasquirt for a while. I never got on with it, even trying a
couple of different valves I couldn't get a consistently steady idle, and they seemed to leak slightly under boost. Both were very sensitive to
the pulse rate, and at 10Hz both made a bloody awful noise!
I ended up doing away with it completely and adjusting the throttle body stop until it idles nicely. It needs a couple of blips to keep it running
from a cold start but then stays rock steady. Much simpler!
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pjay
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| posted on 1/8/12 at 06:36 PM |
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No experience of the stepper motor IAC (looked at it but a lot of faff) but I have recently plumbed in an IAC valve to my GSXR1000 K1 ITBs and wired
it to the FIDLE line on my MicroSquirt (MegaSquirt).
I've configured my MicroSquirt so that whilst the coolant temp is below 60*C the FIDLE is grounded and the IAC valve is open and bleeds extra
air into the inlet. This gives approx. 100 rpm increase whilst the engine warms up and then the line goes open circuilt and the valve closes returning
to the standard idle.
Overall good results for now but really need to try it out in the depths of winter.
HTH
Pete
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coozer
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| posted on 1/8/12 at 06:53 PM |
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I thought about this for a bit, then added a choke cable to the tb's to 'just' lift the throttle to raise the idle.
After some issues with the throttle hanging open on the over run, did away with the choke cable and used my right foot. It really only needs a bit of
throttle for the first few seconds to keep it running then its fine.
Not worth the effort on our type of car going to the expense and added complexity IMO.
1972 V8 Jago
1980 Z750
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pjay
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| posted on 1/8/12 at 07:42 PM |
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quote:
Originally posted by coozer
I thought about this for a bit, then added a choke cable to the tb's to 'just' lift the throttle to raise the idle.
After some issues with the throttle hanging open on the over run, did away with the choke cable and used my right foot. It really only needs a bit of
throttle for the first few seconds to keep it running then its fine.
Not worth the effort on our type of car going to the expense and added complexity IMO.
Thought about this myself but had a 'purge valve' and connector that came free with the engine and it only needs a 12V supply + FIDLE line
(e.g. two wires, supply and fuse). Would have been more complex and expensive for me to buy the choke, cable, nipple etc. and then route it and fit it
somewhere in the cabin. Appreciate if someone else has the cable etc. already it's probably a better bet.
Would agree though it's less to go wrong but just fancied the challenge as well!
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coyoteboy
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| posted on 2/8/12 at 10:37 AM |
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I run a bosch 3 wire IAC valve on my squirted tin-top. Took a bit of faffing but I had it pretty well nailed after half an hour or so's
tinkering, there is a distinct sweet spot on it though. Makes the car much more "OEM" - imperceptible change of idle as it warms up which
is much better than when I was trying to use it just as open or shut, or even just two PWM values for hot/cold which are only right and fully drivable
when either fully cold or fully warm on my car.
I did spend forever trying to control a wayward warm idle that kept dying when cold and revving high when warm. Then I realised I'd not adjusted
the physical throttle stop to zero.
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Chaz
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| posted on 2/8/12 at 07:29 PM |
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Thanks for the replies.
Still not sure which way to go with it yet.
I'd imagine the stepper idle is more accurate but the plumbing seems just like more work! With no huge gains. Would still be nice to start the
MK without having to faff with throttle blipping though.
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Valtra
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| posted on 13/5/13 at 12:21 AM |
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quote:
Originally posted by coyoteboy
I run a bosch 3 wire IAC valve on my squirted tin-top. Took a bit of faffing but I had it pretty well nailed after half an hour or so's
tinkering, there is a distinct sweet spot on it though. Makes the car much more "OEM" - imperceptible change of idle as it warms up which
is much better than when I was trying to use it just as open or shut, or even just two PWM values for hot/cold which are only right and fully drivable
when either fully cold or fully warm on my car.
I did spend forever trying to control a wayward warm idle that kept dying when cold and revving high when warm. Then I realised I'd not adjusted
the physical throttle stop to zero.
Is the Bosch 3 wire classed as a stepper motor or a pwm / on-off valve just need to know as mine made the relay rattle like hell so I had to disable
it in tuner studio , now read that Microsquirt can't control a steper type fidle valve
"If it looks like it works and it feels like it works, then it works"
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Bare
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| posted on 13/5/13 at 02:36 AM |
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Stepper motors have More than 3 wires. .. up to 6 and even 8 wires. Entirely different animal than the Bosch Crap.
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Valtra
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| posted on 13/5/13 at 07:20 AM |
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quote:
Originally posted by Bare
Stepper motors have More than 3 wires. .. up to 6 and even 8 wires. Entirely different animal than the Bosch Crap.
"If it looks like it works and it feels like it works, then it works"
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BaileyPerformance
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| posted on 13/5/13 at 09:59 AM |
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if its any help we do not use any form of idle control on our conversions, we just use "cold advance".
If you get it tuned correctly it will start from cold without any throttle and idle. Small amount of throttle maybe required on very cold days but
once warmish it will be fine.
www.baileyperformance.co.uk
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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coyoteboy
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| posted on 13/5/13 at 12:14 PM |
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My 3 wire effectively works as a force-open-force-closed bypass. You PWM it in closed loop to give an average airflow. It's original fit on my
car and works flawlessly with stock ECU or megasquirt. It does, however, require a driver circuit to run from the PWM output, it cannot be run
directly. I'm not sure if the Bosch unit you guys have used is different, but it should operate the same way and should pose no problems.
I have full warm up and closed loop idle with it, it holds +-10rpm with any electrical stimulus and +-25rpm with power steering activation.
But then I tuned my tintop to replicate the stock ECU drivability and it uses both varying advance, fueling and active idle control to achieve good
steady idle across the range with a low compression engine.
[Edited on 13/5/13 by coyoteboy]
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Valtra
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| posted on 13/5/13 at 12:39 PM |
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quote:
Originally posted by BaileyPerformance
if its any help we do not use any form of idle control on our conversions, we just use "cold advance".
If you get it tuned correctly it will start from cold without any throttle and idle. Small amount of throttle maybe required on very cold days but
once warmish it will be fine.
www.baileyperformance.co.uk
Thanks
Yes I can see that it should so its not a priority as you can see from my other postings
"If it looks like it works and it feels like it works, then it works"
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rx7locost
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| posted on 13/5/13 at 03:16 PM |
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I am running a 2-wire IAC (called a BAC in Mazda RX-7 terms) with my MS using the PWM mods. I started out with running it open loop and have now
moved on to running closed loop idle with no real problems. Tuning the cold start curves is a chore as you only get one real chance to tune per
session. But once done, it is really great.
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Bobbyspit
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| posted on 24/5/13 at 07:58 PM |
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Stepper
I am running an IAC stepper motor, Four wires and it works fab.
Although I am at the initial tuning stages, I have set it up to give more air when cold and once warm have adjusted the tickover with the final
setting. A fab and easy bit of kit.
My Stepper came with the throttle body I bought from the US, and was easy to wire up and check on my Stim.
But a spare is available on the bay
NEW Idle air control valve stepper IAC PEUGEOT 406 1.8 | eBay
Worth a go.
Rob
[Edited on 24/5/13 by Bobbyspit]
[Edited on 24/5/13 by Bobbyspit]
Location Perth Scotland
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ashg
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| posted on 24/5/13 at 08:35 PM |
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at the end of the day either will work well if setup correctly. normally the decision is made by what you have or what is easier to fit/mount. bosch
3 wire pwm valves work well and are not too big so easy to find a home.
im using a bosch 3 wire pwm valve set at 100hz on my car. i set the idle rpm statically on my car using the throttle body screw at 800rpm when warm
with the idle valve closed and only use it to increase rpm for warm up. if the engine is mapped correctly as bailey said it will idle happily without
a valve just using ignition and ve idle advance.
if you look on the efi analytics website phil has released a beta of tuner studio with warm up wizard, i have been playing with it and must say its a
nice little feature.
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
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