$EE VSS Question

[n8sh4de]

I'm analyzing at the moment, why my cruise control doesn't work after a transmission swap in my '95 corvette.
First some facts to my situation:

-VSS circuit error #24
-Old transmission 40 vss pulses per rev, new transmission 2 pulses
-speedo, odo and fuel consumption info works after reprogramming pcm
-cruise control and speed adjustment of the radio doesn't
-RT tuner logging showed constant 0 mph during driving, all other values worked correctly

Now I've realised, that the speedo ist just controlled by the "tach out" (WHT) wire from the pcm, while the cruise control and the radio are controlled by the "vss out" (DK GRN) wire, while the LCD gehts the data from the CCM, which just gets the same "vss out" signal as the cruise control.

My idea was that the automatic PCM, can't make a correct "vss out" signal, as the manual vss has very different pulses per rev now.

My second idea was, that the VSS sensor or the wires have a problem. The resistance of the vss sensor was about 440 ohms, meassured at the plug of the PCM. This seams to be quite high. Do you know how high this should be?
So maybe the signal is to weak for a "vss out" signal but still works for the "tach out" signal.

Max

[lionelhutz]

Why did you switch from a 40 pulse to revolution to a 2-pulse per revolution sensor? What transmission swap did you do?

Why would the speedometer be driven from the tach output? The tach is driven by the tach output since that output is rpm based.

I'm not sure how you can re-program the PCM to get the speedometer to work when it is displaying a constant 0mph when you are logging.

[n8sh4de]

I converted from the 4L60E to the ZF 6spd. The ZF has just a 2 pulse sensor, the automatic tranny a 40 pulse.
I just googled, I thought speedometer is just another word for tachometer, my mistake.
(in Germany, we also have the word "tachometer", which is the thing that shows the speed, not the revs)

I'm also not sure, why the speedo works, but all other vss related things like cruise control, radio or logging don't...