Date: Tue, 13 Feb 2007 14:11:49 -0800
Reply-To: Old Volks Home <oldvolkshome@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Old Volks Home <oldvolkshome@GMAIL.COM>
Subject: Re: ECU reset, O2 voltage stability
In-Reply-To: <2b9b38180702131020v78b05cc6x185a0fe8c3a4a961@mail.gmail.com>
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Based on my experience, the Digijet ECU appears to re-set itself when turned
off and then on (it's possible some settings are retained, but not much, if
at all). On a cross country trip last year, I had ECU issues half way back
to So Cal. As I was driving, I would momentarily turn the key off, then
back on to re-set the ECU and it would run fine for about 2 to 3 minutes,
then act up (surging, hesitation at freeway speeds, etc.,). After putting
up with this nonsense for around 20 miles, I finally stopped outside
Amarillo, TX and swapped ECUs (always a spare in the bed/seatbox) and voila,
no more ECU issues. When the Digijet vehicle first starts, it runs in "Open
Loop", disregarding the O2 signal. After about 2 to 3 minutes, it reverts
to "Closed Loop", thus depending on the signal the O2 sensor is giving it.
However (and as jon states), the Digifant retains some settings when turned
off.
The O2 signal is not constant and does flucuate/swing between 0 to .5 volts
when operating.
--
Jim Thompson
84 GL 1.9 "Gloria"
84 Westfalia 2.1 "Ole Putt"
73 K Ghia Coupe "Denise"
72 411 Station Wagon "Pug"
oldvolkshome@gmail.com
http://www.oldvolkshome.com
***********************************
On 2/13/07, Mike Frost <wasserleaker@gmail.com> wrote:
>
> Greetings all,
>
> It's time for smog testing on my 86 2.1L and I am failing for HC and CO.
> So
> I am looking closely at the O2 sensor which was very recently replaced.
>
> My first question is about the Digifant I ECU. I have read many differing
> statements about resetting or clearing the memory of the ECU. Does the ECU
> have any kind of static RAM (memory that does not lose its contents on
> power-down)? Does the computer reset completely when the ignition is
> turned
> off? Some things I have read talk about entering 'service mode' by
> disconnecting the temp II sensor and then 'blip' the throttle 3 times up
> to
> 3000RPM (or 4 times up to 2500). I can believe that there is a service
> mode,
> but I'm having trouble believing that the ECU can 'remember' the state of
> the ignition system after the engine is shut down.
>
> Second question involves the voltage from the O2 sensor. Under idle
> conditions (no change in RPM) I am seeing the voltage swing down to zero
> and
> then back up again to some value above 0.5V when the O2 is connected to
> the
> ECU. Is this normal? I'm guessing that I should see a fairly stable
> voltage
> unless the speed of the engine changes.
>
> Thanks in advance,
>
> Mike
> wasserleaker@gmail.com
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