GMPP E67 LS376 / 480 Speedo

[faust.dr]

I am suffering from the exact same issue with my GMPP LS7 E67 controller. The HPT scanner doesn't display vehicle speed although the VSS signal on the engine harness bulkhead is correctly sending the speed signal to my Racepak dash. In the PID list I do see vehicle speed and there is a corresponding sensor in the sensor list. Could there be a problem with the 2.23 Scanner? A new compile is suppose to be coming out this week so hopefully this will get resolved.

Maybe I will also try deleting the 19211212.os file.

[Chris@HPTuners]

the VSS PID is a generic SAE PID, if it was broken it would be broken for every vehicle we support.

The problem is the ECM is not populating the PID correctly for some reason.

[alan91z28]

Chris based on what is known now as a generic issue it seems with the VSS PID on the GMPP controllers, do you have any suggestions?

Obviously getting speed to be able to log on the Scanner is of great benefit for tuning, etc, so it is an unfortunate one to not be able to see

Thanks
Alan

Also i have not had a chance to try deleting the .os yet but i will over the next couple of days, however it doesn't sound like that is likely to be the issue

[Doubledip]

Hi Guys, I to have come across this.. I deal with holden based tunes and test alot of this on the bench... from what i can test these are the results i see

E38 Flashed by TIS with VZ tune (native REPTOS Speed)
see speed in HP's
see speed output on oscilliscope

E38 Flashed by TIS with VE tune (native SERIAL Speed)
then change in tune with HP's to REPTOS
do not see speed in HP's
see speed output on oscilliscope

i also have a customer who has efilive and said that he cant see speed in it either (now VE Holden based tune) but could before when it was a 2006 corvette based tune

any ideas... i had emailed Bill previous to this discussion and he asked for a scanned log, I havent had time to do it since and havent really worried till this customer has asked the question.. only prob with a scanned log is that the speed will just sit at '0' anyway.

[Chris@HPTuners]

the VSS ouput params only control the VSS output on the PCM, the don't control the PID. I asked for the log becuase i need to see if Trans Output RPM is also reading 0 becuase VSS is calculated from that value. If that value is reading zero it will help me narrow down the issue.

[Doubledip]

no worries... will do it today and email.. Thanks Chris
Sorry Bill for being slack... didnt think to much of it, till now.. it seems like a common problem

[LSX378]

the VSS ouput params only control the VSS output on the PCM, the don't control the PID. I asked for the log becuase i need to see if Trans Output RPM is also reading 0 becuase VSS is calculated from that value. If that value is reading zero it will help me narrow down the issue.

Chris, would it help to know that the TCM VSS PID returns correct speed data?

Unless I am missing something, that answers the question in a slightly different way, and the answer is yes, the VSS PID from the TCM has accurate speed data.

[alan91z28]

Chris,

I tried deleting the .os file as well using the new version of the beta. Didn't effect the VSS display on the scanner as still read a solid zero all the time

I am attaching a scanner log file for your reference, i took this one a couple weeks ago. I can't find any Trans Output parameter in my list of PIDs / Sensors that you are asking about

Again my config is

- LS376 / 480
- E67 GMPP LS367 / 480 ECM
- T56 VSS going to the E67 directly with good output on its hard signal from the ECM

Thanks

[midgetracr]

I am confused (again!). Please define terms:
What is RepTOS?
The 4K signal, is this 4K HZ or 4K pulses per mile or 4K what.

I find these under the Speedo section in the recent Beta, but do not understand what the terms represent.

TIA

[LSX378]

I am confused (again!). Please define terms:
What is RepTOS?
The 4K signal, is this 4K HZ or 4K pulses per mile or 4K what.

I find these under the Speedo section in the recent Beta, but do not understand what the terms represent.

TIA

Yes talk about 3 letter acronyms (TLA's and TIA's LOL!!!), now we are up to 6 letter acronyms RepTOS! SLA's!

RepTOS is "Replicated Transmission Output Shaft Speed Sensor (VSS/Vehicle Speed Sensor).

It is a signal that is "replicated" by the TCM and fed into the ECM as a VSS (Vehicle Speed Sensor) so the ECM has a speed signal. M6's feed the speed sensor signal direct into the ECM. The TCM mimics this after it processes the VSS from the trans out put shaft. (TOSS) There is also a TISS, transmission input shaft speed sensor.

HPT has enabled the speedo processing in the ECM to be changed from being fed by serial via the CAN from the TCM, to hardwired via RepTOS. (A4's and M6's mostly use RepTOS but not always.) Some truck A6's use it too.

GM terminology, but probably applies generally.

4,000 pulses per mile is sort of an industry standard for speedos.

So the aim is 4kppm from the ECM for the speedo. Or in metric countries, about 2500ppkm.

Hope that helps man!

Now if only the HPT gurus (the ones with the Guru pins ) can somehow wake up the ECM VSS PID for logging on these recalcitrant ECM's.

[Doubledip]

Now if only the HPT gurus (the ones with the Guru pins ) can somehow wake up the ECM VSS PID for logging on these recalcitrant ECM's.

so going by this it seems to answer my original question that in a holden VE i cant see the vehicle speed on the HPT scanner


funny though because in a VZ Holden setup it does display... they are both E38's but i guess the OS must play silly buggers


i rechecked the other day and still the same.

[midgetracr]

Thanks LSX378. That helps a lot. Don't know why I could not figure out what RepTOS meant on my own <grin>.

The Speedo section in the latest Beta 2.23 has new parameters shown. One of them is "Replicated Transmission Output Shaft Speed Sensor (VSS/Vehicle Speed Sensor)".

This parameter is set to "Disabled" in my stock LS376/480 map. I'll try to enable this. Hopefully it will resolve my problem of having no VSS output on the bulkhead connector and no speed signal available to log in HPT.

[LSX378]

Thanks LSX378. That helps a lot. Don't know why I could not figure out what RepTOS meant on my own <grin>.

The Speedo section in the latest Beta 2.23 has new parameters shown. One of them is "Replicated Transmission Output Shaft Speed Sensor (VSS/Vehicle Speed Sensor)".

This parameter is set to "Disabled" in my stock LS376/480 map. I'll try to enable this. Hopefully it will resolve my problem of having no VSS output on the bulkhead connector and no speed signal available to log in HPT.

I hope your hope works on the ability to log the VSS PID/data, but my guess is that will take some HPT guru magic if it doesnt.

[Doubledip]

I hope your hope works on the ability to log the VSS PID/data, but my guess is that will take some HPT guru magic .

I think the logging VSSPID/Data will come down to the OS running in the ECU as i know it works for certain Holden Cars

[midgetracr]

Finally had time tonight to turn "ON" the HPT parameter called "Replicated Transmission Output Shaft Speed Sensor (VSS/Vehicle Speed Sensor)".

Now with my GM LS376/480 wiring harness' VSS plug plugged into my Tremec TKO transmission's VSS output, I finally have an output on the wiring harness's Brown #4 wire on the output bulkhead. Hooray!

Ran out of time but hopefully tomorrow I'll be able to drive the car and test for a VSS signal via the standard HPT data logging setup. If this does not work, I should still be able to feed that signal into the VCM interface auxiliary inputs to get Vehicle Speed into my HPT logs.

Will keep everyone posted. Thanks again to LSX378 for defining terms.

[midgetracr]

Ran a log tonight during a 50 mile pleasure ride. I how have a reliable Vehicle Speed (SAE) in my logs.

The calibration is wrong but this is easily fixed. Problem solved for my LS376/480 GMPP crate engine with E67 VCM.

Thanks to HPT for turning on the "Replicated Transmission Output Shaft Speed Sensor (VSS/Vehicle Speed Sensor)" and Vehicle Speed Output parameters in the new Beta 2.23.

[LSX378]

Ran a log tonight during a 50 mile pleasure ride. I how have a reliable Vehicle Speed (SAE) in my logs.

The calibration is wrong but this is easily fixed. Problem solved for my LS376/480 GMPP crate engine with E67 VCM.

Thanks to HPT for turning on the "Replicated Transmission Output Shaft Speed Sensor (VSS/Vehicle Speed Sensor)" and Vehicle Speed Output parameters in the new Beta 2.23.

Cool .

So the SAE VSS PID popped up once you had set just RepTOS to enabled?

Not so lucky here with G8 OS's . Speedo works, but no VSS still.

[alan91z28]

Could you please elaborate on what parameters you adjusted?

On my LS376/480, as noted above with the RepTOS enabled i am getting a good 4000 PPM signal out of the bulkhead connector that i can drive my speedo with, that now works great

I though still do not get any feedback in HPTuners Scanner for Speed...

I have in mine Vehicle Speed Output Output Source set to RepTOS... this turned on the 4000PPM

I have Wheel Speed Output Parameter Disabled (this was the GMPP setting)- Did you Enable this?

Thanks

[midgetracr]

"Wheel Speed Output Parameter Disabled". Yes this was changed to enabled. Also used the Beta 2.23 .cfg file which includes the Vehicle Speed (SAE) logging parameter.

I also changed pulses per rev from 40 to 17 and set tire size correctly. The logger speed now matches my Autometer Speedo. I think I'm all set. Try this, I hope it works for you.

[LSX378]

"Wheel Speed Output Parameter Disabled". Yes this was changed to enabled. Also used the Beta 2.23 .cfg file which includes the Vehicle Speed (SAE) logging parameter.

I also changed pulses per rev from 40 to 17 and set tire size correctly. The logger speed now matches my Autometer Speedo. I think I'm all set. Try this, I hope it works for you.

LOL . If that is as it seems, it would be quite amusing if it has been sitting there staring us all in the face the whole time!

Maybe it needs a slight name change: "Populate VSS PID with Speed Data".