Speedometer Issues

[OldSchoolFormula]

Well, I've tried LS1tech for a while looking for answers and have never found any. Heres the situation, I have an LS1/4L60E and Stewart Warner Gauges. The Programmable Speedometer has never worked right since I started the car ~6months ago. These are my findings - Basically, at idle or driving below 10MPH the speedo acts erratically, bouncing between 140-160MPH, and then corrects itself at speeds above 10MPH. Today I discovered that if I shut the engine off while driving, and leave the ignition on, the speedo reads correctly even at speeds below 10MPH, perfectly smooth as it should be. This is coming from Pin 50. If I try to tap into the VSS high coming off of the transmission, the speedo will work at all speeds while driving, but the transmission will not shift. It will just hang in 2nd gear. If I disconnect the VSS completely, I still get pulse counts from the PCM as indicated by the speedo. I've tried moving grouns around as well as power, and nothing seems to improve the situation. All I end up doing is further butchering of my wiring harness.
Today I even went as far as installing a new PCM thinking that maybe I'm getting crosstalk or some kind of interference inside the PCM. No dice. I also previously bought a Dakota Digital SGI-5 to see if that might help the problem - it did not.



Anyone have any ideas? Better yet, anyone in the bay area have a programmable Autometer that I could try to see if the SW gauage is the problem, even though it SHOULD work? I have $500 into this thing now and am really getting upset with it.

Thanks for any and all help...

[TonyL]

There's a shop in northern california. We use them for everything. Give them a call, and they'll help you out.

Speedometer electric
29 E 11th St
Marysville, CA 95901
(530) 742-2611