3 wire idle valve question

[mike_tosen]

Using ms3x 3.75

Wiring is fine - idle valve works perfectly minimum 28 maximum 88 - steps through the range nicely.
Its driven on idle and nitros2 oms the ms3x card.
Resistance from center pin to the each side is round 13 ohm each.

Bench testing the 3 wire idle valve and noticed the following.

With the valve turned of - in the idle control menu - the "Run valve before start" is set to off - with this setting the idle valve heats up(slowely - dont think it is serious), and the idle pin is open, and the nitros2 is grounded, I take that is done to drive the valve close ?
Is this intended and normal behavior ? it will not damage the ms ?

With the "Run valve before start" set to on - it's operated at normal pwm and at the correct value.

[mike_tosen]

So nobody knows if the one pin gets grounded with the valve off ?

[mike_tosen]

Tested on bench.
Once you go out of closed loop idle, one pin is open, other pin is grounded.
So it drives the valve closed. Sounds right.
Valve is 13 ohm. So the one driver driving the valve closed while driving the car is grounded the entire time sending +/- 1 amp through the megasquirt driver the whole time

Can someone confirm that is ok, or will it damage the driver ?

[mike_tosen]

OK, so it seems that either nobody knows, or the ones that knows just does not feel like answering me

Its a pity as I really do not want to hurt the driver on the v3.57 board by running the valve like that ....

Maybe someone can point me to a email of someone involved in the development of the MS3 that maybe does not post on this board, that can assist me with the answers that I am looking for ?

[dontz125]

The MS3X drivers are rated to 3A, so a steady 1A shouldn't be a big deal.

I am a little surprised that the one driver is ON when the 'Run valve before start' is set to OFF. I would have thought both drivers would be off, leaving the idle valve in a neutral (but half-open) position. James is one of the developers; perhaps click on the red link to jsmcortina further up the page (in the Moderators list) and send him a PM to look at this thread.

[muythaibxr]

Most likely the "valve off" nomenclature should have said "valve closed" since I am betting the code just sets "duty" to 0%, which with a 3-wire valve would shut it all the way by setting the close coil to 100%. Just a guess without looking at the code though.

[mike_tosen]

Thanks, will send him a PM.

It should also be one on and on off when you above idle in normal driveing mode the. As long as this does not create excessive heat while doing say an 3 hour drive somewhere with the one pin grounded the whole time ....
But is it is fine, I will run it that way no problem.

Thanks
Mike

[mike_tosen]

No reply to the pm and no reply here.
Who else can help ?

[jsmcortina]

I am a little surprised that the one driver is ON when the 'Run valve before start' is set to OFF.

This is resolved for 1.4.1

James

[jsmcortina]

1.4.1 now released. Please confirm here that it now works as expected.

James

[mike_tosen]

Thanks, will load new firmware over weekend and test.

[mike_tosen]

1.4.1 now released. Please confirm here that it now works as expected.

James

Its working, thanks