That 94 Jetta ECU has 68 pins and it looks like more than 40 are used.
In contrast the waterboxer 2.1 ECU has 25 pins, 16 used.

Quite a job you have there figuring it all out. Hate to say it but
getting a running donor and then pulling it apart yourself has major
advantages in the end.

Mark

neil N wrote:
> Thanks Mike.
>
> It's labelled a "power supply" relay. I understand it supplies power
> to the ECU.
>
> But you've raised a good question.
>
> Does an ECU typically need power (from 50 connection?) to provide
> power to ECU so it temporarily supplies grounds to relays such as the
> fuel pump?
>
> I'm beginning to think that part of the problem, is that fuel pump and
> ? is not getting power during cranking cycle.
>
> Neil.
>
> On Wed, Apr 16, 2008 at 1:45 PM, Mike S <mikes@flatsurface.com> wrote:
>> At 03:50 PM 4/16/2008, neil N wrote...
>>
>>
>>
>>> I guess the simple question is, as per the diagram, do 3/86 and 2
>>> actually connect to the relay?
>>>
>>  No. The diagram is just showing the internal connections on the relay panel
>> - those terminals are probably intended for use with a different vehicle
>> and/or engine, and definitely with a different relay.
>>
>>  Based on the small section of the diagram shown, I'd guess that is the load
>> reduction relay. Terminal 30 is battery +. The ECU brings terminal 5/86a
>> high to remove power from unnecessary components during cranking, so the
>> starter gets more power.
>>
>
>
>
> --
> Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
>
> http://web.mac.com/tubaneil
> http://tubaneil.googlepages.com/
>