Date:         Thu, 25 Feb 2010 08:15:17 -0500
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: testing Hall sender
Comments: To: Raymond Paquette <raymondpaquette@GMAIL.COM>
In-Reply-To:  <5d903de81002250443m11bbba8fq6954d3e2b2b91804@mail.gmail.co m>
Content-Type: text/plain; charset="us-ascii"; format=flowed

Dear Raymond,

Sorry not to answer earlier.

At 07:43 AM 2/25/2010, Raymond Paquette wrote:
>no spark
>no sound from injectors (that I can hear-is it reasonably loud?)

It's a quiet little tick.  Very easy to hear with a mechanic's
stethoscope (or screwdriver), maybe not so easy without.

>fuel pump cycles on and off at consistent points in the engine revolution

That says that the pulses from the distributor are getting to the ECU
and being processed.

Check the coil negative for pulses using a neon test light.  Or get
your brother-in-law to wet his finger and test the coil negative that
way.  If it's working and he grounds the same hand (to keep away from
the heart) he'll definitely notice it.  If no pulse, check it for +12
with ignition on and engine motionless.  If none, check the coil +
terminal for +12.

If you're getting +12 on both sides of the coil but no pulses, that
pretty much leaves it to the ECU itself or wiring from ECU to coil,
especially if the injectors are firing.  I would be completely
unsurprised if you had a bad solder joint on the ignition driver
transistor (and probably lots of other ones too).  If the injectors
aren't firing, still points to ECU internals or bad connections.  One
side of the injectors should be at +12 continuous; the other side
pulses to ground in order to fire the injector.

I recently examined five ECUs of varying age, both Bosch and T-A.  I
found many many solder joints with fatigue failure in all of them.

Yours,
David