[urq] Electrical question

Thatcher Hubbard thatcher.hubbard at gmail.com
Fri Aug 5 22:03:06 EDT 2005

Okay, I guess I understand this stuff less well than I hoped.  If I
was looking for the pin location to plug the +12v line of the power
harness for an 034EFI system in I'd put it in A11 or E2?  And by
"comes out", do you mean in three wires (for the F/TCU, OXS and FP
relay) from the same pin or that they're wired in series?  I'll read
your post too. I promise I won't remain this much of an idiot for
long, I pick stuff up pretty quickly, but wiring is new to me.

On 8/5/05, Tony Lum <tlum at flash.net> wrote:
> Thatcher Hubbard wrote:
> > Hi all,
> >
> >   Does anyone have any idea which pin on which connector to the back
> > of the fusebox (under dash) provides the ignition-switched 12v to the
> > stock ECU?  I've looked at the wiring diagram in my Bentley, which
> > doesn't seem to contain that information, or maybe I just don't know
> > how to read it correctly?
> On the old fuse box, the switched +12V, aka the "15" line enters the fusebox at
> the black connector pin 2 or E2 as shown in the wiring diagram. It comes out(at
> least in theory) on pin A11 to feed the F/TCU and OXS frequency valve and fuel
> pump relay coil.
> >
> >   I guess while I'm at it, does anyone have any idea how the fuel pump
> > relay wires work into that?
> >
> The fuel pump relay coil is fed by A11 and the F/TCU grounds the other end of
> the coil at pin 16.  The 30 contact of the relay comes from the H connector and
> the switched end (87) goes out to feed the fuel pump through a 16A fuse and a
> very long wire.  I wrote a long post regarding this wiring back on 9/18/2001
> detailing my fixes for this underdesigned circuit.
> HTH,
> Tony
> '83 urquattro #302

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