Date: Fri, 6 Jan 2017 17:16:00 -0500
Reply-To: David Beierl <dbeierl@ATTGLOBAL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Beierl <dbeierl@ATTGLOBAL.NET>
Subject: Re: PS Pump switch high idle question
In-Reply-To: <2F1732BE-A22C-4650-A206-31CB5DF93CCB@shaw.ca>
Content-Type: text/plain; charset=UTF-8
When the PS switch yanks the line high -- and I do mean yanks, it's
connected directly to alternator B+ via the harness <cough>no fuse<cough>
-- it commands the ICU to increase the duty cycle. You can measure this
directly using your voltmeter in duty-cycle mode across the valve input
pins with ignition on but engine not running. Short across the PS switch
taking infinite care not to ground it, and watch the reading. Same with
the A/C and cranking signals.
Christmas isn't until tomorrow -- signed, Mister Scrooge. ;-)
Yrs,
d
On Thu, Jan 5, 2017 at 10:57 AM, Alistair Bell <albell@shaw.ca> wrote:
> David,
>
> Right, but when the ps switch is closed....?
>
> Btw, happy Xmas :-)
>
> Ab
>
> On Jan 5, 2017, at 3:36 AM, David Beierl <dbeierl@attglobal.net> wrote:
>
> The controller sends a fixed frequency pulse train to the valve, ?250?
> Hz. The valve responds to the average duty cycle and opens proportionally,
> but you can hear it hum at the fixed pitch while it's active.
>
> Yrs,
> d
>
> On Wed, Jan 4, 2017 at 12:12 AM, Alistair Bell <albell@shaw.ca> wrote:
>
>> Ok got it. With the effect of allowing more un metered air into the
>> plenum.
>>
>> Thanks
>>
>> Alistair
>>
>>
>>
>> > On Jan 3, 2017, at 8:41 PM, Dennis Haynes <d23haynes57@hotmail.com>
>> wrote:
>> >
>> > The increase in duty cycle effectively opens the valve further.
>> >
>> > Dennis
>> >
>> >
>> >
>> > -----Original Message-----
>> > From: Alistair Bell [mailto:albell@shaw.ca]
>> > Sent: Tuesday, January 3, 2017 10:51 PM
>> > To: Dennis Haynes <d23haynes57@hotmail.com>
>> > Cc: vanagon@GERRY.VANAGON.COM
>> > Subject: Re: PS Pump switch high idle question
>> >
>> > So it's as I guessed, the pulse cycle is biased towards more ICV valve
>> open time when PS switch closes. But hold on, I misread, your saying the
>> pulse bias opens the ICV further and not a bias towards on time?
>> >
>> > Thanks Dennis
>> >
>> > Alistair
>> >
>> >> On Jan 3, 2017, at 7:43 PM, Dennis Haynes <d23haynes57@hotmail.com>
>> wrote:
>> >>
>> >> The PS pressure switch is an input to the idle valve controller. There
>> is also an input for the AC compressor clutch. The idle controller looks at
>> engine speed, temperature, and those other inputs and then modulates the
>> valve to get to the desired speed. The modulation is based on providing a
>> pulsed current to the valve coil. The duty cycle is increased to open the
>> valve further.
>> >>
>> >> Dennis
>> >>
>> >> -----Original Message-----
>> >> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
>> Behalf Of Alistair Bell
>> >> Sent: Tuesday, January 3, 2017 10:03 PM
>> >> To: vanagon@GERRY.VANAGON.COM
>> >> Subject: PS Pump switch high idle question
>> >>
>> >> Hi,
>> >>
>> >> Can someone school me on the way the PS pump switch affects the idle
>> speed? I have a faint idea that it somehow changes the pulse to the ICV,
>> I'm supposing it results in a balance that has the ICV open longer.
>> >>
>> >> Thanks
>> >>
>> >> Alistair
>> >
>>
>
>
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