I am no VECII expert, but in general, what piggy-back computers do is alter signals from various sensors in order to trick the stock computer into doing what you want. For example it would alther the oxygent sensor voltage in order to trick the stock computer into adjusting the fuel mixture in closed loop differently than it would without the piggy-back. And might trick the crank positioning or cam position sensor in order to affect timing. It might use an absolute manifold pressure sensor adjustment to effect open-loop air fuel. So you still have to have sensors working.HMMM. I still do not understand how it works (VEC Noob). . . What confuses me is that if the VECII is telling the pcm what to do fuel and timing wise, would it not have to bypass the O2 to get this done.
Keep in mind that the VEC2 is only used at WOT
Keep in mind that the VEC2 is only used at WOT
That is incorrect.
KenH:
that still is not correct, the VEC2 can be used to modify either closed loop or open loop (WOT). They are a bunch of reasons to modify closed loop.
Correct me if I'm wrong, but I believe the stock PCM controls the fuel and spark advance through an open loop system up to around 80% of WOT. It will "adapt" based on various outside parameters. Beyond 80% the fuel and spark advance are controlled by a closed loop system using fixed pre-set factory maps. The vec II controls ignition and spark advance based on manifold pressure and/or RPM. If you adjust the injector pulse width and/or ignition based on RPM but only have them take effect at a manifold pressure at or near zero, then, in effect, they will only occur at WOT. However, adjustments at negative pressures (i.e. vacuum) or positve pressures (i.e. boost) are also possible.
VIPER D...
Can you please give a little more info on what you had to do for your NOS control and shift light? I haven't read ALL the documentation yet, so if it's in there feel free to give me the big "RTFM".
There's no output terminals (i was expecting screws or something) so did you have to add a few new pins to the harness? Does the VEC2 software have a section for setting these option or did you have to "hack" something?
I've really only messed with pulse widths so far.
Thanks
Tony:
there are actually two PWM outputs, one in the master and one in the slave. The problem is they are linked by a common on/off state.
Hi. We installed the shift light and vec 2 in Viper D's car. We used the PWM Load and PWM RPM to fire his NOS/Propane between 3000-5000RPM. The shift light in the cabin we triggered by using LED 2 on the VEC 2 itself, which is controlled by the Box Configuration.
Hi. We installed the shift light and vec 2 in Viper D's car. We used the PWM Load and PWM RPM to fire his NOS/Propane between 3000-5000RPM. The shift light in the cabin we triggered by using LED 2 on the VEC 2 itself, which is controlled by the Box Configuration.
So is there some way to tap into the LED #2 light on the VEC2 box to drive the shift light? As it doesn't seen to have an output on the I/O harness.