URQ freq valve trigger

[DGraber460@aol.com]

My new to me black #472 URQ 10V K26 is puzzling me a bit. The Frequency  
valve will not work consistently. I just spent the last week removing and  
replacing the down pipe & 02 sensor but no change. The valve itself is not  the 
issue. If I plug other known good units into the wiring harness they don't  buzz 
either.
Other than the 02 sensor and the ECU (BTW I'm using the one from my old car  
that worked fine) what other items/sensors could be the culprits?
If I unplug the 02, the valve buzzes and the car runs  crappy. Plugging the 
02 back in it shuts down again. The 02 I'm using  was the one from my old car 
that ran great.
TIA
 
Dennis
Denver