causes for a non-functioning FV???(4ktq)

[Orin Eman]

Never mind about 6 and 34.  They are the CA and AT indicators (don't
know which is which).  CA cars have one grounded. AT cars have the other
grounded.

> > There is more than one ground to the ECU - pins 34, 18, 6 and 9 at least.
> 
> I verified good ground to 9 and 18. 6 and 34 have NO path to ground either
> with ignition on or off.  My bentley shows pins 6 and 34 going to brown
> stripped wires to ground connection 91 which is "welded -1- wiring harness,
> electronic ignition".  Perhaps this may be the culprit???  Where is ground
> connection 91?  Why are they stripped wires?  are they switched with
> something?

There are some loops on the first page of the wiring diagrams
which show how the 'grounds' are interconnected.

I pulled out some MAC11 guts.  Pin 9 is the ground that is used
for the frequency valve (and some other solenoids).  It is not
connected to the other grounds inside the MAC11.  I'd double check it.

> > Also make sure pin 2 gets a good ground through the ignition booster
> > or strange things can happen.
> 
> Hmm... I checked pin 2 vs a solid ground and I got 1.77 ohms.  Is this
> acceptable or too high?  Additionally I got .654 ohms between pins 2 and 22
> (the two wires going to the ignition booster).  Where does the ignition
> booster get its ground from?

I think it gets it from being bolted to the firewall.
Look at it carefully, you may see a wire sneaking out
bolted to the metal frame of the booster.

Bentley diagrams for the ignition booster vary from
wrong (84-88) to showing a short circuit for some
89-91 models.

Orin.