Pablo

iTrader: (1)

I accidentally purchased a 2 prong VSS sensor for my T5, turns out the TbI puter and etc uses a three wire sensor. What i can tell is the difference is the two wire generates its own power while the other is powered.. and the ground looks a little different. However both are 4000 pulses per mile right? I tried wiring it up anyways with just the output and the ground and left the power out (maybe i have the polarity mixed up on the sensor cuz its not marked) It doesnt work
Can it work? or do i just need to get the three wire sensor?
thanks
Pablo

[This message has been edited by Pablo (edited November 11, 2001).]

Grumpy

I believe you have apples and oranges here.

The TBIs I know of use the optical sensor in the back of the speedo. It is power, ground, and out.
The later cars use a 2 wire A/C generator that plugs into the tranny.
The 747/optical units are 2000 pulses per mile.
If you tranny uses a speedo cable then just getting a Speedo Cable Inline VSS will work. www.jagsthatrun.com probably as the VSS you want (the inline).
I'm pretty sure of what I've written forra double check talking to Jags the run or Riverside Speedometer in Riverside CA could verify what I've said.

Grumpy

BTW, designing a black box with a comparator, and flip flop might be an answer but the inline deal would be cost effective.

Pablo

iTrader: (1)

thanks for the reply grump, im not sure what you mean though about the optical sensor behind the speedo, Do you mean that it has a mechanical speedo and the input to the ecm is read from the optical sensor behind the actual speedo? If thats what you meant then thats not the case with my car i believe firebirds had a vss run speedo incorporated earlier than camaros, theres no speedo cable. The reason im doing this is because the tranny was installed without any sensor (swapped from an auto) the only plug thats down there for the speedo is three wire like you described, power, grnd, and out and according to the wire schematic in the chiltons manual (I know, i know..) the original was 4000 pulses per mile too but wasnt optical it was something else i cant recal at the moment but i do recall seeing the optical doodad for the earlier car schematics and it was different
thanks