Date:         Sun, 17 May 2020 11:43:14 -0600
Reply-To:     OlRivrRat <OlRivrRat@COMCAST.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         OlRivrRat <OlRivrRat@COMCAST.NET>
Subject:      Re: Idle issues
Comments: To: Pat Spragge <spraggepat@GMAIL.COM>
In-Reply-To:  <F60CCB4D-F378-4831-BDF4-BDD07F79FA79@gmail.com>
Content-Type: text/plain; charset=utf-8

                Patrick

        The Relay that resides Beside the FuelPump Relay in the BlackBox is the ECU Power Relay

not the ICU Relay ~ There is no Relay involved in Power to the ICU ~

        The ICU & Idle Control Valve Should Be Powered any time the the Igni'Key is in the On Position ~

                                                                                ORR ~ DeanB

On 17 May , 2020, at 9:43 AM, Pat Spragge wrote:

> David,
> 
> My understanding (while very basic) is that the ICU is powered through the relay that resides next to the fuel pump relay, but I am unsure what the sequence of events are that would trigger the relay to close and thus power the ICU. Does the initial, key on, pulse that triggers the fuel pump operation for a few seconds also closes the ICU relay which then operates the idle valve for a short burst and then once the engine starts and the fuel pump is operating continuously so does the ICU and idle valve? So if the ICU relay was not functioning, the idle valve could be good (confirmed via bench test) and the ICU could also be good, but the idle control “system” would not be working?
> I ask this because I seem to have an issue similar to Steven’s, difference being that I have no idling problems. I have an ‘89 Westy and haven’t been able to feel the idle valve vibrating. I put in a new ICU that Peter from VanCafe loaned me but that made no difference. I also had the valve “bench tested” and it functioned. I haven’t done a deep dive on this since my idle is rock solid, but suspect that everything is fine. I would, however, like to confirm that the idle system is working as intended.
> I get nervous about probing voltages around semiconductors (ICU) and the Bentley doesn’t seem to go into troubleshooting the ICU/RELAY/VALVE beyond the vibration test.
> 
> Patrick 
> 1989 Westfalia 
> 
> 
>> On May 17, 2020, at 2:51 AM, David Beierl <dbeierl@gmail.com> wrote:
>> 
>> On Sun, May 17, 2020 at 12:21 AM Steven Mills <lefthanddrive123@gmail.com>
>> wrote:
>> 
>>> Idle control valve does not vibrate/hum but will open/close on bench test.
>> 
>> 
>> So -- valve is good but system is not operating.
>> 
>> 
>>> So, my question centers on whether or not the ECU can partially function
>>> but still be dysfunctional as to the idle. Any thoughts/ideas would be
>>> appreciated.
>>> 
>> 
>> The ECU does not control the operation of the ICU.  If the valve does not
>> hum at key-on (or when the fuel pump runs in late models) then either the
>> ICU or its wiring is bad (since the valve is known good).
>> 
>> Yrs,
>> d
>> 
>>> 
>>> Sent from my iPad