Speedo input

[Asho88]

Will not having a speedo input connect how the car drives? If so in what way? Can settings be changed to run without a speedo input? Vh 253 VN Top swap using traumatic on $12p cheers

[Deuce]

On an electronic auto it will right royally stuff your shift maps (I've driven 2 blocks without the VSS plugged in).
But being a trimatic and 12p I cannot think of anything the VSS would do tune related.

[Asho88]

Cheers mate was starting to lean that way but I wasn’t 100% sure cheers

[antus]

It has a lot to with controlling the idle air, and idle modes. Without it, your more likely to stall as you pull up because it thinks your cruising. There is a parameter where where you set the speed which below the idle stuff is operating. I think default is 20kph from memory. Without the VSS (Vehicle Speed Sensor) you don't get that functionality and will have more trouble with return to idle.

[Asho88]

Ok that makes sense so won’t affect the VE map though? I’m just troubleshooting tried taking it for a drive and every time I go to drive off it just leans out. Was having TPS issues cleared those finally. Map threw a high volt code so swapped that out. Tried adding fuel on the fly and doesn’t make a difference like somethings interfering with it

[antus]

Well as above it might get confused about transition to or from idle. EG if the car starts moving and it thinks you free revving AE might not kick in to give it the shot of fuel it needs. But I don't have enough familiarity with the inner workings of the code to say for sure. I usually just think of it as every single sensor is there for a reason and every single sensor you remove has some negative effect somewhere. The ECM has fallbacks, usually with compromise, just to get you home to fix your car. If it worked the same without VSS, then they would not have put it in the car. Mostly you are talking about transition from stopped to moving, so a missing speed sensor is probably related.