I've hijacked this thread, but thought the topic belonged in this forum so....
To recap, I have 5 magnets on the driveshaft being read by a hall effect sensor on the tranny.
With the Vehicle Speed Sensor wire disconnected, the car runs more or less normally unless I let the RPMs drop too suddenly, and then the engine will stall. I can baby it, and get it to idle, though sometimes doing this, it goes into what I think is "limp mode" and it runs rough, shudders, has no power etc. Turn it off and back on, and it's back to normal - running normally and dying after dropping from higher RPMs.
When I hook up the VSS wire, the car runs perfectly until roughly 33mph. It doesn't want to die at stops and seems to run stronger while driving (might be my imagination). But when it hits 33, it seems to cut spark. If I keep it over 33 (going down a hill) the car will die. If it drops below 33ish, it will start firing again.
This seems to me like I have the wrong number or readings per rotation so I'm trying to figure out the math as I'd prefer to bust off the magnets and glue them back on only one more time if possible - skipping the trial and error.
I'm pretty sure that the VSS wants to see 4000 pulses per mile.
The vanagon/EJ swap VSS kit which I'm using a part of, uses 5 pulses per wheel rotation.
I'm pretty sure the rear diff ratio is 3.9:1 like the brats?
My wheel and tire diameter is ~22.5" which I think give me about 47.5343 rotations per mile..
From here, I'm a bit stuck. Any ideas?
Edited by julianco, 24 January 2014 - 02:15 PM.