fabricating a VSS?

[usergone]

I would be sure to "bench test" the sensor before installing it for a VSS, using a multimeter or oscilloscope or whatnot, and of course a 12v supply. Stick a screw or screwdriver on the end (it is slightly magnetic) and see if the output goes low (0v).

The driveshaft is not spun to the right position, but you can probably get the idea.


On a slightly different note, I am surprised that it has stuck around so long. My cold welds must not be that bad after all.

[thefenixgang7]

I will try to test it tomorrow as it is getting rather dark.
What did you use to cold weld it? And when did you do it?

[usergone]

Oh, I didn't mean "cold weld." I meant that my regular mig welds didn't get hot enough for proper fusion.

[thefenixgang7]

Do the bolts cause any vibration or were they pretty well in balance? Using a mig welder didn't get hot enough to cause damage to the rear seal in the trans? What ppm are you getting?

[usergone]

I cut the carriage bolts to the same length, and welded them on the opposite sides of the driveshaft (as best I could tell) and have not noticed any weird vibration.

NOTE: I didn't say I didn't notice vibration. If my jeep stopped shaking and vibrating and got real quiet on the road, I would be scared.

As far as the welding, the welds didn't get hot enough because I was afraid of melting stuff in the transmission or the U-joint right there.

I don't even remember what PPM I have it at, but I figured it out by pushing the jeep until I saw a pulse (the beginning of a pulse, that is), and marking the road right where that was. Then I pushed the jeep until I saw the beginning of another pulse, and marked the road there. That will get you the distance between pulses, and with a bit of math, you can get pulses/mile.

I think that I also calibrated it further by comparing the speed according to my MPGuino to the speed shown on my GPS. Then use a formula similar to the one for calibrating the gas consumption. I believe it would be something like: (MPGuino speed/GPS speed)*current ppm value = new ppm value (I think that is right, but you may need to switch the MPGuino speed and gps speed)

[thefenixgang7]

I was referring to added vibration, my jeep makes many shakes and vibrations.
I believe I will weld the same setup with a slightly different bracket for the sensor.
Pushing it till you get a pulse sounds like a good way to get a 'ball park' figure, but wouldn't driving a long distance (such as 350-400 miles) then comparing to the mpguino be a more accurate way to set it rather than speed?

[usergone]

Originally Posted by thefenixgang7

Pushing it till you get a pulse sounds like a good way to get a 'ball park' figure, but wouldn't driving a long distance (such as 350-400 miles) then comparing to the mpguino be a more accurate way to set it rather than speed?

Probably

[thefenixgang7]

Well it ends up that my sensor was bad, I ordered a 'spare' a few days ago, it should be in soon. As a test I got a crank sensor from a chevy 3.1 at the local parts store. It only has 2 wires, so I wired it up to see if it would work, and it works, but not right. It does not even start showing speed till i am well over 45mph, it is accurate at 65mph, but by time I stop it says I am still going 35ish, and its slowing down while I am at a stop. I am not sure if the speed is in real time on the mpguino or if it is delayed, but either way its wrong at every speed tested accept 65mph. Any ideas? Maybe just install the new sensor when I get it?

[usergone]

I don't even know where to go with that. For me the VSS was super simple to rig up as soon as I got a bracket made for it. You can't see it, but I put a rib on the back side of the bracket for added rigidity, so it wouldn't go banging into one of the bolt heads.

[thefenixgang7]

Actually, I can see the welds on the side showing. I will just install the new sensor when it comes in.
Thanks