LS ECU and VSS - Vehicle Speed Sensor??

[2001ultima]

Question. Anyone with a LS engine, are you setting up and using a VSS - Vechicle Speed Sensor? Can you provide any information about the need for the VSS and how you may have set it up. Thanks, Jim

[356Speedster]

2001ultima said:

Question. Anyone with a LS engine, are you setting up and using a VSS - Vechicle Speed Sensor? Can you provide any information about the need for the VSS and how you may have set it up. Thanks, Jim

I believe the GM E67 does need a wheel speed sensor to function properly and is very difficult to tune without. The GM wiring harness has an input for a sensor, so you'll need an appropriate hall-type sensor (the factory should be able to help) and the standard factory trigger wheel on your driveshaft. Oh and bracket to hold the sensor, LOL!!

Here's my setup.... note the second sensor feeds the RaceTech Dash2 unit:

[macgtech]

Taking it off the back wheels as opposed to the front is a little out of the normal? Or is it done like this to use traction control using a 'rate of change' calculation?

[356Speedster]

macgtech said:

Taking it off the back wheels as opposed to the front is a little out of the normal? Or is it done like this to use traction control using a 'rate of change' calculation?

I believe this is the way it's always done on Ultimas.... certainly when I spoke to the factory, I wasn't made aware there was an option for front wheel sensing. The only drawback I can see is that when the rear wheels spin, the reading will be incorrect (but if my rears are spinning, the speedo is the last thing I care about!!).

[738 driver]

A few have done the fronts.. ford ABS trigger wheels/sensors I think. When combined with an LSD and traction control requirement .

[macgtech]

738 driver said:

A few have done the fronts.. ford ABS trigger wheels/sensors I think. When combined with an LSD and traction control requirement .

Exactly what I have in mind. We were going to take the WS off the front brake disc mounting bolts (a common method in race applications) but now we are redesigning the uprights, we will take it off the locking collar on the spindles we are using. The rear's will be off the trans output as shown above.

[ROWDYRENAULT]

If anyone has purpose built brackets for the front uprights, to locate a sensor to read off the brake mounting bolts and wants to sell a set I am all for avoiding building something from scartch. Lee

[Storer]

I don't have a VSS on my LS7 set-up and the standard GM ECU seems to work without one.

I take my SPA Dash speed reading off the rear driveshafts with no problems.


Paul

[Steve_D]

My understanding (which could well be wrong) is that the VSS is primarily about controlling the auto transmission. The lesser function is about idle control ie are you throttle closed at a standstill so idle is required or are you on overrun in which case the ECU could go into fuel cut for economy.
The info I have seen does not indicate you have to have it in use.

Steve

[738 driver]

Meant to add.. many inputs/parameters in the E67 were switchable within EFI live software (although the engine tuning side itself favours a Guiness Guzzler to be competent).. I dont see why speed sensing could not be deselected.