Idle Air Control Valves - Why I'm Not a Fan!

[Belle427]

Stumbled across this thread as im having a bit of a nightmare trying to figure out what my stepper is doing on my Megasquirt conversion.
Car is running well but I cant quite work out what its doing and any adjustments don't seem to be having any effect.
It either wants to idle too fast or today decided it wanted to stall the engine on various occasions.
Ive tested it before to confirm its actually moving back and forth but I will do that again tomorrow.
Im tempted to try blanking it as suggested and see how it goes,i just wondered how many run without the stepper motor?

[DaveG]

The Stepper works fine for me with Megasquirt. I have used it in both Open and Closed Loop for the past 7-8 yrs. What are your settings.



Here is a log of my Idle, quite steady with stepper moving from 20 to 19 to compensate for changing air temp, etc. When the fans come on there is a corresponding change in stepper position and spark advance. (Nb. the spark correction wordking).



Here is the averaged data for the period:

Edited by DaveG on Monday 11th November 00:52

[ChimpOnGas]

The solution in my case was simply to remove the poor quality Chinese no name idle air control valve as supplied with my Canems installation and replace it with something better.







I didn't buy a Bosch original, I went with a German made copy from Lowe, I purchased it for £50 direct from the factory in Berlin including delivery to me here in the UK, and it works perfectly. I only use it for cold start, closed loop idle managed when the engine is warmed is handled by scatter spark, the two systems work together to deliver truly OEM idle management.

Original new old stock Lucas stepper motors are no longer available and the quality of the copies are a bit hit and miss from what I hear, so I would definitely consider replacing your old Lucas stepper motor with the Bosch rotary type idle air control valve from Lowe, for just £50 you get a brand new quality made infinitely variable valve your MegaSquirt system can control perfectly.

In my opinion its definitely worth investing £50 for a guaranteed solution

[Belle427]

DaveG said:

The Stepper works fine for me with Megasquirt. I have used it in both Open and Closed Loop for the past 7-8 yrs. What are your settings.



Here is a log of my Idle, quite steady with stepper moving from 20 to 19 to compensate for changing air temp, etc. When the fans come on there is a corresponding change in stepper position and spark advance. (Nb. the spark correction wordking).



Here is the averaged data for the period:

Edited by DaveG on Monday 11th November 00:52

Thanks for that, my settings are similar but my power between steps setting is currently on hold current, not sure what is recommended.
My homing direction is set to closed too., I’m sure the 14cux homed it open.

Edited by Belle427 on Monday 11th November 07:38

Edited by Belle427 on Monday 11th November 08:10

[ric355]

Belle427 said:

Thanks for that, my settings are similar but my power between steps setting is currently on hold current, not sure what is recommended.
My homing direction is set to closed too., I’m sure the 14cux homed it open.

The 14cux homes the stepper to the fully open position when you turn off the ignition. Either approach works fine - you have to set up the rest of the system accordingly of course - but for the 14cux method to work you have to have power to the ECU and ancillaries for a bit after the ignition is turned off. Often aftermarket ECUs aren't wired this way. You could home fully open at key on too of course; all combinations can be made to work and there isn't much between them.

[Belle427]

Id be interested to see your cold start settings if possible, thats where im having most trouble.
Im particularly interested in the cranking pulse and after start enrichment as i think im happy with warm up enrichment.

[DaveG]

Here you go Belle427.
These are mine, but note I am in Oz and it is a bit warmer down here (Melbourne). Winter temperatures usually between 5-15 degrees C and summer 25-35. I am currently working on a "Cool day Tune" and a "Warm day Tune". (VE impact!)









It all takes time to match your engine to the conditions.

[Belle427]

Thank you.

[Belle427]

Those cranking and afterstart figures are interesting, they seem quite high for a 20 degree start.
How does the car start from cold with those?
Mine turns over for a few seconds, fires and needs throttle input for a minute and then it stabilises, im finding this part of the tuning quite frustrating.

[spitfire4v8]

Ms does seem to over complicate this side of things, here's a screenshot of the emerald software showing the start up and after start and running corrections all on one page.

Edited by spitfire4v8 on Thursday 14th November 09:23

[Belle427]

Certainly looks far easier.
What I'm struggling to comprehend is the high percentage values on some of the graphs.
I'm happy enough with the warm up enrichment values but it's the others I cant make any sense of.

[Sardonicus]

spitfire4v8 said:

Ms does seem to over complicate this side of things, here's a screenshot of the emerald software showing the start up and after start and running corrections all on one page.

Edited by spitfire4v8 on Thursday 14th November 09:23

Too true you could interpolate some of those settings with MS and still get to where you want hats off to Emerald in that respect

[spitfire4v8]

Belle427 said:

Certainly looks far easier.
What I'm struggling to comprehend is the high percentage values on some of the graphs.
I'm happy enough with the warm up enrichment values but it's the others I cant make any sense of.

Run what's required to get the job done .. always dangerous to look at other maps imo.