67ls1CamaroProject

I finally hooked up my EASE scanner to find the VSS code. I had a reading of 0.0 for the speed at all times. I had wired the speedo per the directions and recomendations from their tech support line. That is from the VSS on the tranny directly to the speedo and then from the "sig out" terminal to the PCM. Well the PCM doesn't like this. So, I spliced it back into the VSS line so that it now goes to both the speedo and the PCM and I do not use the "Sig out" anymore.

Results:

Now all of a sudden I can easily shift into reverse. Apparently before the PCM was turning on the reverse lockout solenoid and I had to jam it in gear. Much nicer now. Also, the car use to struggle to stay idling when coming to a stop. That's fixed now as expected. I am not sure why the reverse lockout was on when the speed indicated 0.0. I thought the PCM had to think it was going faster than 3mph before turning that on? Oh well...the proof is in the real world.

70 LS1

iTrader: (1)

Glad to see it all worked out for you and thanks for the tip. I plan on installing an Autometer speedo pretty soon.

LS-1st-Gen

Ok heres my unique autometer situation. My TPIS wiring harness arrived with the wrong VSS connector on. (The connecter I recieved actually would fit in a plug on the passenger side of the trans, obviously not the right place). I said no, went to GM and purchased the correct VSS plug for the T56. Problem #1 The plug GM sold me has 2 white wires. Problem #2 I have a purple and a green coming from my harness. I took my best shot and put the old plug next to the new plug with the clips facing up and matched the purple wire to the white wire on the corresponding side of the new clip, and the green wire to the other side. Problem #3, my VSS could be now wired backwards....how can I tell?

Problem #4 I call autometer to ask which wire to hook up my speedo, he says use trail and error, I hooked up the purple wire because I remember someone saying on this board that the green is the ground. The problem now, of course, is that I could have the whole freakin thing mismatched and nothing works. I'll be test calibrating the speedo this weekend...who knows maybe I got lucky

any thoughts?

Speartech

iTrader: (14)

When hooking the wires up at the speed sensor on the trans, it doesn't matter which way you hook them. It's a sine wave output, so the signal is the same either way (kinda like unplugging the lamp in your living room and turning the plug over, the lamp still works the same).

I think we've done street rods here now with all 3 of the main gage makers (VDO, SW, and Autometer), but I forget about the Autometer for sure. Do they give you some options on how to hook up their speedo?? Most of todays gages will actually do better if you leave the VSS wires alone and use the SPEED OUTPUT from the PCM to run your speedo.

Like I said, we've just recently finished a car with VDO gages and one with SW gages and I know these had the option of which signal to use, but I forget on the Autometer.

Lesrace82

iTrader: (8)

speedo output from the PCM wouldnt work for my autometer speedo. it would work fine for a while, then just start jumping all over the scale.

LS-1st-Gen

John- Autometer instructs me to splice into the VSS NOT the PCM output, apparently the PCM alters the signal in some way.
So what your saying is Im fine at the transmission connector>>??

67ls1CamaroProject

Splice is what works for me. I informed them at autometer which is why they have changed their story to "splice" instead of "interupt". Direct from the VSS(sine wave). The PCM output is buffered (square wave) and will not work.

Speartech

iTrader: (14)

You're fine at the trans connector. Sounds like Autometer can't use the PCM output signal. Splicing is the only way to go.