VSS Question
02-01-2019, 11:25 AM
#1
VSS Question I am working on a LS swap into a BMW E34. I am starting to do a little bit of the wireing and I had a quick question regarding the VSS, I am using a 5.3 as a base engine and harness from an 01 Silverado and a TR6060 from a 12 Camaro I believe. The car has a speed sensor on the diff so I was wondering if the VSS wiring could be removed from the engine harness, or does it serve a purpose in a manual trans car for more than just the speedometer?
02-01-2019, 02:52 PM
#3
02-01-2019, 03:30 PM
#4
Several things at work here -- and I'm certainly no expert. I believe the ECU uses the VSS signal to help manage what occurs, for example, when you're off the gas decelerating to a stop, and the injectors are basically turned 'off' to conserve fuel. If the ECU knows how fast the car is going, it can manage smoother transitions back to idle mode - which require the injectors to be reactivated. Some folks complain of manual tranny's wanting to stall when coming to a stop if no VSS signal is present. Many have said you can tune your way around this -- or a knowledgable tuner can tune their way around it. From my research a few years back, I think the 6 speed manual and the auto trannies have different tooth counts on their reluctors. Seems one has a 17 tooth reluctor and the other a 40 tooth reluctor - the smaller number in the manual tranny. So your ecu will be expecting one or the other in terms of pulses per mile. I've also read folks say that just about any VSS signal will give the computer what it wants to manage this. I use the manual tranny sensor on a homemade 9 tooth reluctor mounted on the pinion flange and mine seems to work just fine. No idea if the auto plug and the manual plug are the same....
Whole different can of worms if you need the VSS to also serve an electronic speedo -- you have to figure out how to give the ECU and the speedo precisely what they want. Tuners can help with that also.
Whole different can of worms if you need the VSS to also serve an electronic speedo -- you have to figure out how to give the ECU and the speedo precisely what they want. Tuners can help with that also.
02-01-2019, 08:06 PM
#6
Michael and Gary are correct. The vehicle will likely have stalling issues without the PCM knowing the car is moving. For motion purposes the signal doesn't need to be accurate but it does need to be consistent. The closer to accurate the smoother things will be.
...and before someone says "I don't have a VSS signal and my car is fine..." I'll say this is like many things - it can work without one but it will be closer to optimum from the start with the VSS installed. Besides it's only two wires.
...and before someone says "I don't have a VSS signal and my car is fine..." I'll say this is like many things - it can work without one but it will be closer to optimum from the start with the VSS installed. Besides it's only two wires.
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02-02-2019, 08:24 AM
#8
I really do appreciate everyone’s input here. So I will keep all the VSS input pins and hook up a new VSS plug for the TR6060. I will talk to the tuner about the trigger wheel just so it is closer to a Camaro.