Using a Cable driven VSS with speedo ratio adapter box
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Using a Cable driven VSS with speedo ratio adapter box What would be the proper way of installing the VSS (Dakota digital 8k ppm) pass thru with a speedo ratio adapter box?
Tcase output--> VSS--> Ratio Box
or
Tcase output--> Ratio Box--> VSS
This will be on a 5.3/NV4500 w/ doubler/ dodge NP205
Originally my Dana 300 Output with 35's and 4.88 gears was perfect with stock output and with 5.38s and 40's its pretty much spot on too, but I'm assuming going to the new tcase may change that ratio. I likely wouldn't know how far off it is until I was able to Match it to GPS speed when doing 50- 60 Mph.
Thanks for any insight.
Tcase output--> VSS--> Ratio Box
or
Tcase output--> Ratio Box--> VSS
This will be on a 5.3/NV4500 w/ doubler/ dodge NP205
Originally my Dana 300 Output with 35's and 4.88 gears was perfect with stock output and with 5.38s and 40's its pretty much spot on too, but I'm assuming going to the new tcase may change that ratio. I likely wouldn't know how far off it is until I was able to Match it to GPS speed when doing 50- 60 Mph.
Thanks for any insight.
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Just trying to wrap my head around it.
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I do want to eventually be able to use cruise control with a dash mounted 4 button deal (Dakota digital or the like) that is wired into the TAC module.
The pulse rate of the dakota digital VSS is not high enough to work with the stock ecu. I had to use the reverse gear (39 tooth) on my T10 to get my DBW cruise control to work.
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Interesting Gary thanks.
I did find this over at HPtuners
https://forum.hptuners.com/showthrea...l-8K-Pulse-VSS
Saying there is the possibility of changing the signal in the ECM.
I did find this over at HPtuners
https://forum.hptuners.com/showthrea...l-8K-Pulse-VSS
Saying there is the possibility of changing the signal in the ECM.
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Yes they suggested using their SGI-100BT which just amplifies the Signals for tach and speedo ref. But it's another $150 and adds more wiring mess into the mix.
This is why I was hoping to be able to just have the ECM adjusted to read the 8k ppm signal. Which seems doable I just need to find the right tuner.
I'm starting to think you'd want to run the VSS after the ratio box so the ECM is seeing actual speed at the 8k ppm.
Watching Brendans (LT1Swap) Vids on Youtube The cruise uses a 4k ppm Signal from the ECM. So the ECM must convert the OE 40k ppm signal.
Last edited by Winchested; Sep 13, 2022 at 08:20 AM.
You can adjust the ecu to read the correct speed, it's just the rate is not high enough for the dbw cruise control to work correctly. It wnt from idle to wide open every second. ECU read correctly, but doubt the ecu was reading a stable signal for cruise.
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I might just abandon the cruise option for now. The wiring is there. Can buy the Dakota digital box later on ,the 4 wires are all set up from the TAC module connector so it would just be tying in the clutch disengage, brake and brake switch.
I assume with a manual I don't need the TCC wire I added a pin for the Clutch switch on pin 35. Don't want to run the clutch engaged for start switch, I'll just get that code deleted in the tune.
Yes, tried it with the DD VSS, no luck even with the correct speed tune on the ecu. Used the 39 tooth reverse gear in my T10 as a reluctor, worked fine. Oh yaeh, I did have to retune for the correct speed since the ecu thought I was going 140mph at 35 mph and limited my top speed, lol.