Date: Fri, 24 Dec 1999 07:50:26 -0600
Reply-To: Darrell Boehler <midwesty@MIDWEST.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Darrell Boehler <midwesty@MIDWEST.NET>
Subject: Re: Woody's digitool / digijet running rich
Content-Type: text/plain; charset="iso-8859-1"
Hi Woody,
Thanks for your purchase and here is some information about your new
digitool. I post it to all because the digitool displays nothing that is not
available to someone with a meter and a hat pin to stick in the desired wire
one needs to observe.
The temp1 sensor lives inside the afm and measures the air temp.
Temp2 measures the coolant temperature and lives in the thermostat
housing.
o2 sensor lives in the exhaust before the catalytic converter.
The afm wiper voltage is developed inside the afm by the wiper /
resistor.
PWR led indicates the ecu has battery power.
STR led indicates the starter solenoid is being told to energize.
FP led indicates the fuel pump relay is being energized by the ecu.
TS led indicates the throttle valve / butterfly is at idle or full
throttle.
Coil led indicates the coil is being pulsed by the distributor and ignition
module digijet and by the distributor ecu on vanagon digifant.
Fi led indicates the ecu is pulsing the injector.
These are all important for proper operation of the engine or they would not
be in the system. In your case I would check the temp2 to see that it is
about 0.1 volt when the engine is warm, anything below 0.3 is ok. Above
about 0.3 the system will not go into closed loop (closed loop is when the
o2 sensor samples o2 in the exhaust and sends a voltage to the ecu, the ecu
inturn will open the injectors longer or shorter duration depending on the
o2 voltage). Check the o2 sensor voltage to be around 0.4 volts when
first started. It will rise to about 0.6 volts as the o2 sensor warms up 2-5
minutes depending on outside temps. After the engine and o2 are warm / hot
the o2 voltage will bounce above and below 0.5 volts several times a minute.
This bouncing above and below 0.5 volts is a good thing and should make you
happy. (^_^) It indicate your engine is running a perfect mixture. If your
o2 voltage is above 0.5 volts your engine is running rich, if below 0.5
volts it is running lean.
You mention the digitool indicates voltage and not resistance of various
sensors as the bentley suggests. Resistance is an ok thing and that is the
easiest way to check the various sensors with out a digitool. However with
the digitool the voltage readings are displayed with the flip of a switch.
The ecu makes decisions based on the voltage it receives from the sensors.
The digitool is displaying live data going to and from the ecu allowing you
to notice anomalies dynamically as they happen, much better imho. Rant mode
off.
Merry Christmas vanagons and their people also.
Darrell Boehler
Makanda Illinois
