I have removed the factory ECM, and am installing a Fast XFI 2.0 controller. From the factory VSS I can hook into the the XFI controller. The question is the VSS output that was created by the factory ECM. In the red book page 8A-33-3 it says the ECM amplifies and converts the sine wave created by the VSS to a square wave and this is what is supplied to the CCM. I was thinking I could tie the output wire to the signal wire, but now it looks like I need a converter?

IIRC, the VSS generates an A/C signal.

This should be the ticket:

http://www.dakotadigital.com/index.cf ... =287/mode=prod/prd126.htm

I had a SIMILAR problem converting to auto in my car.

MIGHT have the answer SOMEwhere in old posts / PC doc's, but hands are FULL ATM...

I had a DD SGI-5, but it turned out NOT necessary..........................

edit:
I'm SURE I have the answer here TJP; will dig by end of day here...

I can't answer your question directly.

I found this related to the VSS signal:

1. The two-pulse (2000 pulses per mile) square wave (D.C current or direct current) used on all TBI
engines thru 1992, all computer-controlled-carbureted engines, and on 1985-1989 TPI engines.
2. A four-pulse (4000 pulses per mile) sine-wave (A.C. current or alternating current) signal is
required by the 1990-1993 TPI, 1992-1993 LT1 engines, and 1990-1993 Camaro 3.1/3.4 V6
engines.

On 3rd Gen it is recommended to use a buffer box. This might be something to look into:

http://www.thirdgen.org/forums/dfi-ec ... -fast-xfi-vss-wiring.html

I'm looking through Z boards where I wrote up VSS problem in my conversion. Other notes are in another computer...

Exactly what are you asking here TPJ? What is the problem?

Can you post a schematic of what devices you have to tie together?

Quote:

No real issue. I thought I could get away without a converter. By conecting the VSS signal wire and VSS output wire together, but found out the ECM converts the VSS signal then sends it to the CCM. I will get a converter to do this, so I will have a speedometer. The reason I thought I could get away with this is that the XFI accepts the VSS signal from the trans.

Alright - I got the question; VSS signal INPUT, TO my tranny control module, FROM VSS, is adjustable.

The default setting is the correct value. I do not remember at the moment; I will pull it up tomorrow here.

My TCM then gets the correct signal for ECM, TO CCM (or whatever the channel is).