Need to Know How to Test an Optical VSS
#1
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Car: '87 Camaro
Engine: 4.3L V6
Transmission: T5
Axle/Gears: 2.73
Need to Know How to Test an Optical VSS
I've been living without the VSS working for 5 years and I wanted to figure out what was wrong, so used this procedure to test it (but just with a voltmeter, not oscilloscope):
http://www.youtube.com/watch?v=WR_vdU1b1rs
Positive on top, negative, signal on bottom. I spun it and I only saw an increase of a half a volt on the signaling phase instead of 12. I have a used spare that I just got off ebay that claimed to be good and it acts exactly the same.
What am I missing here? Is my procedure wrong or am I just lucky enough to have two dead VSS units?
By the way, for some reason I had 12v at the ECM end of the harness for the VSS whether the vehicle was moving or not. I checked again with the cluster out and it's at 0. Continuity is good between the cluster connection and the ECM end of the harness.
http://www.youtube.com/watch?v=WR_vdU1b1rs
Positive on top, negative, signal on bottom. I spun it and I only saw an increase of a half a volt on the signaling phase instead of 12. I have a used spare that I just got off ebay that claimed to be good and it acts exactly the same.
What am I missing here? Is my procedure wrong or am I just lucky enough to have two dead VSS units?
By the way, for some reason I had 12v at the ECM end of the harness for the VSS whether the vehicle was moving or not. I checked again with the cluster out and it's at 0. Continuity is good between the cluster connection and the ECM end of the harness.
#2
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Car: '87 Camaro
Engine: 4.3L V6
Transmission: T5
Axle/Gears: 2.73
Re: Need to Know How to Test an Optical VSS
Update: I probed every wire that has to do with the VSS on the cluster and on the main harness and everything seems fine, but what I don't understand is why I still have a constant 12V on the signal wire going to the ECM with the cluster installed. It seems like it should be the crappy 0 - 0.5v signal I get when I test the VSS on the bench.
I'm out of ideas for testing this besides buying a new optical VSS for almost $100.
I'm out of ideas for testing this besides buying a new optical VSS for almost $100.
#3
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Join Date: Jan 2007
Location: Holly, MI
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Car: '87 Camaro
Engine: 4.3L V6
Transmission: T5
Axle/Gears: 2.73
Re: Need to Know How to Test an Optical VSS
Well, this seems to be the proper operation for the VSS. I have a wiring issue on the body wiring somewhere. I've bypassed the wiring with some test leads and I'm reading proper speed input on the scanner.
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