Originally Posted by
TotalVelocity
I double check all the wiring and everything. All of it is right. Will a bad altinator do this?? b/c right now 2 diodes are bad in the rectifying bridge which will create a flow of AC in my electrical. Will this cause the oil pressure to be fooled?? B/c my Vtec still isnt working if not how can i tap into the block for oil pressure. (manual reading)
No, a "bad", (as in doesn't put put any voltage) alternator should have no effect on VTEC engagement... Try running the car without the alternator connected. (only drive down the road to see if VTEC engages)
VTEC engagement is controlled by DC voltage, not AC.
Check your VTEC grounds... If they are corroded, it could cause enough of a resistance to disble VTEC, but not enough to throw a CEL? This is unlikely...
Another thought, knock sensors use AC voltage to to detect knock. Maybe if your alternator is putting AC voltage into the computer, it could be causing a it to recognize this AC as knock, and severely retard the ignition and disable VTEC from engaging.
If the computer sees knock, it will NEVER activate VTEC because it would surely damage the motor. Hence the 93 octane requirement. If u use an octane with a rating less than 91, this introduces knock, and the computer compensates by retarding ignition timing and disabling VTEC.
Try this... Simply drive with the alternator disconnected. (make sure it is fully charged so u don't get stuck on the road). If VTEC engages, its the alternator.