BoxsterLS376 introduction - LS3 conversion :)

[BoxsterLS376]

Originally Posted by dcdrechsel

Boxster ls376 -knew about the tach -was hoping you had connected the vehicle speed input from the abs to the gm ecu .The fundamental issue is what are the abs vss signal characteristics ?Once that is known should not be hard to convert to gm specs .
Perhaps you could point me to some likely sources to figure out what that signal is ?
Thanks

Ahh ok my bad. Are you trying to get the traction control working or something? Not sure why you need the GM ECU to see the ABS stuff otherwise. Almost sounds like you are trying to get the speedo to work, which in that case I can't really help either as the Boxster picks up the speed from a plug on the transmission. Does the 911 pick up speed from the ABS?

Regarding the ABS signal stuff - The short answer to your questions is unfortunately no. Google was my best friend during the build but that was not something I ever dealt with, sorry.
Thanks
J

[dcdrechsel]

Originally Posted by BoxsterLS376

Ahh ok my bad. Are you trying to get the traction control working or something? Not sure why you need the GM ECU to see the ABS stuff otherwise. Almost sounds like you are trying to get the speedo to work, which in that case I can't really help either as the Boxster picks up the speed from a plug on the transmission. Does the 911 pick up speed from the ABS?

Regarding the ABS signal stuff - The short answer to your questions is unfortunately no. Google was my best friend during the build but that was not something I ever dealt with, sorry.
Thanks
J

Need the vehicle speed for emissions drive cycle tests .The ecu needs to know the car is moving The 996 abs right rear wheel sensor is used for the vehicle speed signal .The abs control unit does something to that signal .Don't know what and so far google doesn't know either .
Thanks for the speedy responses

[BoxsterLS376]

Originally Posted by dcdrechsel

Need the vehicle speed for emissions drive cycle tests .The ecu needs to know the car is moving The 996 abs right rear wheel sensor is used for the vehicle speed signal .The abs control unit does something to that signal .Don't know what and so far google doesn't know either .
Thanks for the speedy responses

You are welcome. Hrm... Yep never had to deal with that. I simply installed the GM ECU OBD plug in the trunk of the Boxster and tell the emissions guys to plug into that one. Voila~

GM ECU don't give a crap about speed etc. - are emissions very strict in your area? Any reason you can't just direct them to the GM plug? Here we just drive to the little booth, they plug in, see that it is OK, then you're good to go. No intense inspections of any kind.

Thanks
J

[dcdrechsel]

[QUOTE=BoxsterLS376;532424]You are welcome. Hrm... Yep never had to deal with that. I simply installed the GM ECU OBD plug in the trunk of the Boxster and tell the emissions guys to plug into that one. Voila~

GM ECU don't give a crap about speed etc. - are emissions very strict in your area? Any reason you can't just direct them to the GM plug? Here we just drive to the little booth, they plug in, see that it is OK, then you're good to go. No intense inspections of any kind.

Thanks
J[/QUO

Unfortunately I need the drive cycles .

[Bayley]

Unfortunately, I too have the same issue with vehicle speed signals.

The short answer is that there is no easy way to do this with simple wire splicing.

The PCM uses a frequency generated signal to measure inductive pulses through a "tone wheel" inside a GM transmission (usually on the output shaft). If you try to splice into an existing ABS sensor wires, you are now inducing a second frequency into a sensor that is already getting excited by the ABS module. Neither module will be able to read the sensor correctly in this case.

The best concept / idea that I came up with is to add an additional tone-ring to the inboard CV joint of a drive axle. Next, fabricate a bracket that would hold a factory GM vehicle speed sensor up to that ring. You would then need to recalibrate your ECU properly match the tone pulses to actual vehicle speed, but I see no reason why this shouldn't work.

Good luck and let us know if you come up with anything different.

[dcdrechsel]

Originally Posted by Bayley

Unfortunately, I too have the same issue with vehicle speed signals.

The short answer is that there is no easy way to do this with simple wire splicing.

The PCM uses a frequency generated signal to measure inductive pulses through a "tone wheel" inside a GM transmission (usually on the output shaft). If you try to splice into an existing ABS sensor wires, you are now inducing a second frequency into a sensor that is already getting excited by the ABS module. Neither module will be able to read the sensor correctly in this case.

The best concept / idea that I came up with is to add an additional tone-ring to the inboard CV joint of a drive axle. Next, fabricate a bracket that would hold a factory GM vehicle speed sensor up to that ring. You would then need to recalibrate your ECU properly match the tone pulses to actual vehicle speed, but I see no reason why this shouldn't work.

Good luck and let us know if you come up with anything different.

Dakota digital has a gps sender that I think will work .It is compatible with the gm ecu and looks like a simple , clean installation .If I hit many more dead ends that is what I will try .I keep thinking there is a way to take the speedometer signal and convert it to a ac sine wave for the gm ecu .So far -no .