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

[Nate Stuart]

> Hi Orin!,
>
> > 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?

Remember, pins 34 and 6 are for ECU code options. Pin 34 is for a California
car, and pin 6 tells the ECU it is working with an auto trans. So in your
app. Marc these two should not be grounded.

> > 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?
>
>
> > What is the resistance of the frequency valve?  Has it gone open/short?
>
> No.  The FV itself is fine.  I don't recall the actual resistance value,
but
> Nate measured that and mentioned it was ok I believe.

I don't recall actually measuring the resistance across the FV coil, but we
tried two different FVs.

> Irregardless I don't
> see a duty cycle of 50% at the CO tap which tells me something is up.
Your
> 2 first comments had me rushing out to the garage since I hadn't checked
> either of those.  I think you are on the right track....

Exactly why I/we didn't think the actual FV was the culprit. There was _no_
duty cycle coming from the ECU whatsoever. Didn't make any difference if the
FV was connected or not, no duty.

Later!
-Nate
'86 4kcs(soon to be t)q www.mswanson.com/~nstuart
'87 5kcstq (donor, need parts!?) www.mswanson.com/~nstuart/audisale.html