Date: Mon, 27 Jul 1998 15:23:56 -0500
Reply-To: Darrell Boehler <midwesty@TAOS.MIDWEST.NET>
Sender: Vanagon Mailing List <Vanagon@vanagon.com>
From: Darrell Boehler <midwesty@TAOS.MIDWEST.NET>
Subject: Re: Digitool
Content-Type: text/plain; charset="iso-8859-1"
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Hi All,
A big thanks to Jim. He is doing a good job of testing the tool. And
I think he has some good fresh ideas. So I am thinking of increasing the
digijet tool cable to 20 feet and the digifant tool cable to 15 feet. This
will allow installation of the tool anywhere in the van.
The coil signal used on his digijet tool is ECU pin 1 from the ignition
control unit. This gave us a bit of a problem Friday and I modified the
tool circuits and all seemed good. However since Jim mentioned he
experienced some stumbling in the rain with no coil pulses and I think
this would shut down the fuel pump relay. I think there are several
reasons it would be best on the digijet to use coil minus instead of the
digijet ECU pin 1. With the LED attached to the coil minus we would know if
the coil its self was being impulsed and if we had no spark the coil is
instantly suspect. The coil LED would not effect / be an excessive load for
the coil driver transistor. This will mean adding an extra short wire to
the cable attached to the digijet ECU and eliminating the wire to ECU pin 1
, but the added value of better information is well worth the time and
trouble. Coil minus is what is used and has much testing with the digifant
tools .
Jim prefers a tool with back lit LCD that could be mounted in / on the
dash area. I have been searching, ordered and tested some. Most units I
have used are all about 3x1.5x0.5 inches ( 72mmx 36mm) . I prefer using
what is called a panel meter. This eliminates a lot of complex wiring and
circuits that are needed when using just a LCD and grow your own meter and
LCD electronics. I have found 2 units that I like. One is from radio
shack cat no 277 303 and goes for $19 plus shipping. This unit will do
all we want it to do. Big 14 mm numbers, back light, can be wired for common
power supply connections with the circuits we are measuring. The last
feature is important, without it a battery is needed to supply power to the
LCD unit. It has one problem. It requires about 10 solder bridge options
that are a pita. I have also found a panel meter for $11.49 from "circuit
specialists inc." cat no pm-129b It will function for what we need and is
an led type panel meter. It has the common ground feature and would not need
to be back light because it uses a matrix of leds. I will be testing a tool
with the latter led units soon.
-----Original Message-----
From: Jim Maginel <c455ssl@SEMOVM.SEMO.EDU>
To: Vanagon@VANAGON.COM <Vanagon@VANAGON.COM>
Date: Monday, July 27, 1998 12:02 PM
Subject: Digitool
>As Darrell reported, I now have one of his tools connected to my "spare"
>digijet ECU and plugged into the FI system. Darrell is creative and very
>competent with this electronic stuff(unlike myself). I learned a lot while
>he patiently wired up the circuit board in the ECU.
>I did experience some engine "stumbling" while driving in the rain
>yesterday, which I suspect is weather-related and possibly a poor ground. I
>noticed that with each episode of stumbling, both the fuel pump and coil
>LED's flickered. I will take a spin as soon as things dry up to verify the
>moisture hypothesis.
>I like the idea of using the information provided by the tool all the time,
>rather than just to check out problems. To that end, I agree with Darrell
>that making the box somewhat smaller and running on 12-volt power with a
>backlight would allow for easy mounting to the dash, possibly on the
plastic
>panel to the left rear of the shifter.
>I recommend obtaining the digitool if you are interested in becoming more
>informed about the FI system, which in my opinion, contibutes to peace of
mind.
>
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