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So I have a 92 RS 5.0 Manual Transmission. I was going about changing the Vehicle Speed Sensor, i bought one from a local parts store. After getting the one in it out, it turns out they were different. Upon much research it seems that some 90 to 92 third gens with a T56 transmission had an oddball VSS. The part that goes into the transmission is smaller than the others. The problem is that the one I need is out of production everywhere I look, and I have look alot of places and called just as many. I was hoping somebody would have some insight or know a place I can find one of these things. Below I am listing all the part numbers of the various manufacturers who used to make one of these. Thanks to any who can help out. Also I will attach a picture of the two showing the difference.
10456087 GM Part Number
AC Delco 213-196
Factory Number
AIRTEX 5S4656
CARQUEST 72-3624
WELLS SU1024
GM 10456087
ECHLIN VSS218
STANDARD MOTOR PRODUCTS SC40
On the left the VSS I purchased that will not fit. On the right the VSS I pulled from the car.
Then get a standard speedometer bullet and gear and install that into the trans. Wire the 4PAC VSS to the original VSS wires (no polarity). That should do it. But should also seal off or cap the other end of the VSS as it is supposed to be used inline with a speedometer cable.
With a search here I did find this thread (good info & pic in it):
RBob - how does the 4PAC with bullet and gear stay secure in the transmission? I am considering doing this as there are still no aftermarket VSS's available for my car - '91 Z28 305 TPI with 5 speed (10456087 GM Part Number).
The pac2 or painless has a retrofit Vss hooks onto a cable drive bullet insert used on early T5 transmissions.
it probably has a small retainer piece and screw to keep it in the transmission.
Ok, my first searches of bullets did not have the retainer piece in the pics. Makes sense now. Looks like I would build using the parts (or similar) pictured below.
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I’m not sure on the bullet retainer how wide it needs to be. Here’s one option or I think the th350 bullet works. But you might need a driven gear to calibrate the Vss signal.
Good find. I am still troubleshooting some things right now. Next 'experiment' is to run new wire from ECM to VSS. It is still throwing me that the VSS gives signal during drill test and VM is measuring signal at ECM when driving but I get code 24 and speedometer works intermittently.
i have that speed sensor if you are still interested in an original one.
Thanks. I am going to run new wires from VSS to ECM and see if that fixes the code 24. If not, I'll hit you up. Just so odd to me that VM shows voltage from VSS with drill test and when driving at the ECM. Maybe mine is just weak and not producing enough volts. I haven't found anywhere that states what that voltage should be.
I'm hoping my current wires are just getting hot or they have a weak connection and new wiring will correct it. Heck, thinking about it, it could be the connector. Should change that out as well when running new wire.
There isn't a spec for the voltage from the VSS. It does vary from 0 volts up to 100V.
What the ECM/4-out-buffer is looking at is the frequency of the signal. That is what defines the speed of the sensor and thereby the vehicle. For every mile traveled the VSS should output 4K pulses.
There isn't a spec for the voltage from the VSS. It does vary from 0 volts up to 100V.
What the ECM/4-out-buffer is looking at is the frequency of the signal. That is what defines the speed of the sensor and thereby the vehicle. For every mile traveled the VSS should output 4K pulses.
I swapped the VSS I received from Drgnbld. Originally, I kept the yellowish gear that came on his VSS rather than putting my greyish gear on the VSS. First drive and I noticed the speedometer was reading too high. I also threw a code.
So, I swapped the gears and now, after one drive, speedometer seems to be reading correctly and I haven't thrown a code. Now, this drive was short so I am not quite ready to say the issue is corrected, but so far so good.
One oddity, on the first drive after resetting the computer, the speedometer doesn't seem to want to work at first. Second drive after resetting, the speedometer seems to work right away. I'll see how subsequent drives go.
Thanks again to Drgnbld and thank you to TunedPerformance for helping with my VSS issue!
Well, took the Camaro to work this morning. Same oddity about speedometer not working at first, but then starts working, and other than the occasional complete loss of reading (needle drops to 0), speedometer was doing ok. I also still had no code.
Something new though, at least since I got the chip from Tuned Performance, the car had a slight racing idle. This happened all the way until I almost got to work when I threw a code. Once the code threw, idle leveled out. I will check code when I get home this afternoon and see what is going on.
01-26-2019, 11:22 AM
