I think I'll take you up on that...
Otherwise, this is what I'm thinking:
a. maybe the pressure wants to go above 80 but my fuel pump is maxing out. a new fuel pump probably wouldn't hurt. 80 should be enough though.
b. maybe my o2 sensor is screwed up. My hot pipe comin off the turbo is sitting right on the o2 sensor, kinda bending the end of it a little bit. Plus when I took the sensor out, I cleaned it with some starting fluid spray, which I figured wouldn't hurt the sensor at all. But of course now I'm questioning that. maybe a new o2 sensor...
c. maybe voltage clamp connections are screwed up. I soldered them all, but that o2 signal wire only had a really short length of wire to splice because the rest of it was shielded. So I did a lot of yanking on the wire in order to get my hands in there. I checked the ground that I connected the black wire to, and it was definitely a good ground.
d. maybe the voltage clamp setting was messed with (I got it second hand), so I did this:
posted by lokiel on another forum:
"I must start by stating that the FM 2-wire O2 Signal Modifier requires no adjusting, it is already set correctly by FM when it is mailed out so don't "frig" around with it if you don't have to.
I purchased my FM O2 Signal Modifer from another forum member and did not know whether or not it had been adjusted so decided to set it myself. The FM 2-wire O2 signal Modifier instructions mentioned NOTHING about the fact that it did not need to be configured (I've asked them to explicitly state this in the instructions) so I used the 4-wire instructions. They got me confused so I fired off an e-mail to FM and received the following useful information:
"Adjusting and/or testing the signal modifier...
The signal modifier's nominal adjustment range is 5-15 kPa but some can be set as low as 3kPa or as high as 30kPa so it's important to adjust them for your application. You'll need a garden-variety digital multimeter with a diode test or high-ohms setting to determine when the signal modifier is active. When set to one of these modes, the multimeter will generate a test current similar to the signal generated by a rich O2 sensor and when the signal modifier becomes active you will be able to see the multimeter reading change to a different value. The value that you see on the meter may or may not be the actual modified signal voltage, depending on the brand and model of the multimeter you're using. If you don't see a "diode" or "high-ohms" setting then look for a diode icon, which is shaped like ->|- . If using a high-ohms setting then you will also need to set the resistance range for 1-2K. If you're using a "diode" setting then there probably won't be any range options. Connect the + (red) multimeter lead to the white signal modifier wire and the - (black) lead to the black signal modifier wire. With no pressure applied to the signal modifier the reading on the multimeter should be full-scale. When you apply enough pressure to the high side hose barb of the signal modifier (or vacuum to the low side hose barb) the meter reading will fall to a lower value. It is possible that some multimeters could generate a reverse-polarity test current (although we've never actually seen one) an in that case it would be necessary to reverse the meter leads. Connecting the meter leads backwards will not damage the signal modifier ... the meter reading will just stay at full-scale even when the proper activation pressure is applied.
CAUTION ... Don't use an air compressor for testing because applying more than 15psi will damage the signal modifier.
Apply the test pressure (or vacuum) at the desired level and then adjust the pressure setting screw on the signal modifier so that it comes on but is just about to go off. Turning the adjuster screw clockwise reduces the pressure setting. If you don't have a gauge and a pressure or vacuum source, you can estimate a pressure of 10kPa (a typical value) if you have enough lung capacity to blow up an ordinary kids balloon. Just connect a piece of hose to the high-side barb and blow on it about as hard as you would to blow up a balloon. The signal modifier should be set so that it comes on at that pressure. If you want a setting higher than about 10kPa then you will need at least a vacuum gauge and a tee connected to the low side hose barb of the signal modifier. If you can drink a milkshake through a straw then you can suck all the vacuum that the signal modifier can handle, but it's quite difficult to estimate just how much without a gauge. "
I used this information to set my 2-wire O2 signal modifier as follows:
1. Set multi-meter to diode mode (marked as ->|- on my multi-meter).
2. Connect the +ve (red) multi-meter lead to the white O2 signal modifier wire and the -ve (black) lead to the black signal modifier wire.
3. Connect hose to O2 signal modifier's tap labelled High (has white wire on same side of unit).
4. With no pressure applied to the O2 signal modifier, turn the O2 signal modifier's screw anticlockwise so that the multi-meter displays its full-scale setting (eg. 1 on my multi-meter).
5. With no pressure applied to the O2 signal modifier, slowly turn the O2 signal modifier's screw clockwise until the multi-meter reports a value other than the full-scale setting (eg. 464 on my multi-meter). At this point you've gone too far so turn the screw anti-clockwise until it just goes back to the full-scale setting. ANY amount of positive pressure will now activate the O2 signal modifier.
6. Blow into the hose and observe that the multi-meter changes from its full-scale setting to another value (eg. 464 on my multi-meter). When you stop blowing, it will return to its full-scale setting.
7. If you want the signal modifier to activate with more pressure, turn the O2 unit's screw anti-clockwise. Repeat step 5, noting that you need to blow harder this time to achieve the same result. I stopped once I reached what I believe was just under the pressure required to blow up a kids balloon. Hopefully this is < 10kPa."
Except I set it so that basically any positive pressure into the high side would change the setting. So essentially, I'm pretty sure that my voltage clamp is at the right adjustment now, if it wasn't before...but still having problems.