Have you tried just wiring up 2 volts to the lead? I'm not for sure, but I think the knock sensor want's something between 1.4 and 3.5v, if you ground it its gonna freak (whitch it did I hear), of course 12v won't do either. If you have a switched 12v power supply you could always get a few 5-10k resistors from radio shack and make a simple voltage divider. I bet that would work better than any other ghetto rig.
If you want to try it, there's no reason it shouldn't work; Unless the ECU has some complicated programming determined to screw you over becuase the voltage doesn't change. But if thats how it is, then what, your out 1$? Probably cheaper than most other idea's. Anyway if you wanna try it, and you have an 'open' 12v switched these are the ratios you need.
12volts---20k resistor---(1.56Volts here)---3k resistor---ground
If you cant find a 20k or a 3k resistor at radio shack, make sure the ratio is the same, you can go bigger on the 3k, up to about 4k or so, but I definatly wouldn't go lower and not much higher than 4k. Any knowlageable person at radio shack with a calculator could give you tons of combinations to do this with, but I woulnd't count on them being very smart...
The forumla for the voltage in the middle is...
Voltage given * Resistor2 / (Resistor1+Resistor2)
So you have
12 * 3 / (23)
or 1.565 volts. You can use any resistors that give you an acceptable value, but I suggest you keep it close to 1.6v and make sure they aren't small resistors (keep them in Kilo-Ohms) otherwise it will burn out the small resistors becuase too much current will flow. With the 20k and 3k your going to be flowing about 500uA, thats *really* small and you wouldn't even have to worry about it being switched if you didn't want to.
All you have to do after you hook this up is to connect that knock sensor wire to the part I said was 1.56volts, right inbetween the two resistors. I'd get a multimeter and check it real quick though. If it's not an open circuit then the ratios wont be right, but if you buy a pack of each resistor type (3 or 4 resistors), you can definatly make it right somehow.
Lol if you don't want to 'splurge' on the resistors I could spend the 34c to send you an envelope full, their like 1$ for 100 online.
Edit: I'm not Exactly sure on the voltage, if you want it wouldn't be that hard to put the knock sensor back to stock (y'know the 1 Cel every once and a while state?) and stick a voltmeter on it while you drive, it should give you enough info to let you figure out what it should be before the ECU throws a code.
HTH
Buzz1167
Jon N