Expy 03, 4.6l... 45K miles TP Xcal 93 octane performance tune


Sigh.

Using the Xcal's logging tools, I logged a bunch of readings and found one of the two O2's acting strangely. Not reacting would be a better description. I posted pics of the graph previously (now in my gallery) which showed the bank 1 o2 acting normally (switching back and forth rapidly between .9 and .2 volts) and bank 2 reacting very slowly or going flat line. I had mistakenly replaced bank 1 previously with a new Bosch, and of course it is working fine.

Fast forward - I replaced the OTHER O2 with a Bosch and guess what? It is doing the same thing. At certain points on the graph it is actually flat lining at about .6 volts.

I am at a loss as to what to do now. What would cause a brandy-new O2 to react so slowly?

Also, both original O2's have a good degree of carbon build up. Is that indicative of a rich condition? Would that be causing the O2 to be sluggish?

Your help is greatly appreciated.

 

Possibly the new O2 sensor is bad also...................just a guess or your wires are shot...........bad conection.

 

Try pulling a vacuum line to force a vacuum leak. That should make the o2 go full lean. Spray some carb cleaner in the throttle body and that should make the o2 go full rich. The rich problem could be showing a fuel pressure problem.