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Mazdaspeed Archive => Mazdaspeed Miata Tech issues => Topic started by: ECEng on August 24, 2015, 01:16:13 AM



Title: MS or other ECUs and the OBDII port
Post by: ECEng on August 24, 2015, 01:16:13 AM
So I've heard that using a megasquirt unit or something like the hydra ecus render the OBDII port useless in these cars.  Is that 100% true, or is there still come capability left?  I am looking into a data logger unit such as the AiM Solo DL unit, these read using the OBDII port for wheel speed sensors, throttle, and other signals off the open CAN bus. 

Thing is, these units are 400 bucks, and I really don't want to spend that if I'm just going to slap in a new ECU in a year or so, rendering all of my expensive data logging stuff useless.


Title: Re: MS or other ECUs and the OBDII port
Post by: Maduh on August 24, 2015, 01:47:05 AM
Yes the obd2 port becomes useless.

Check this out: http://www.diyautotune.com/tech_articles/megasquirt_displays_and_dataloggers.html


Title: Re: MS or other ECUs and the OBDII port
Post by: Nevyn72 on August 24, 2015, 02:22:56 AM
I believe the only aftermarket ECU that has the OBDII port enabled is the new Haltech Elite series. I'm not sure what functionality is enabled/available though....

Adaptronic looked into it but decided it wasn't worth it or necessary as all the information and more was available via a direct connection to the ECU by a laptop.


Title: Re: MS or other ECUs and the OBDII port
Post by: Maduh on August 24, 2015, 03:07:23 AM
MS has a board you can add that gives data functionality. I think it was only compatible with Reverent built ecu's though.

Also for the record the people who read this thread thinking we're talking about these standalone ecu's providing OBDII functionality to pass emissions, that is not the case. There are no standalone options that can pass emission inspection. This is simply for data to talk with the lap timers.


Title: Re: MS or other ECUs and the OBDII port
Post by: rstange1 on August 24, 2015, 03:43:03 AM
I can't speak for all aftermarket ECUs, but it's pretty simple to make the Hydra talk to your OBDII port if your Hydra is CANbus equipped (I think all of the 2.7 units are). I've done this and have a ScanGauge connected to my OBDII port. The ScanGauge is mounted out of the way above my rear view mirror and gives me four additional digital gauges that I can easily customize to my current situation. Normally I monitor coolant temperature, voltage, air temperature, and also display corrected speed in km/hr. With the Hydra, the ScanGauge will even report boost, which is not possible with the factory ECU. The ScanGauge also has some extended X-Gauge parameters you can program in that are handy for track events (e.g., tell tale displays for maximum RPM, maximum coolant temperature and such). It is very handy and getting it all working only involved some quick configuration in the Nemesis software and running two wires from the Hydra to the OBDII port. Needless to say, you can't pull DTCs from the Hydra, nor will it allow you to pass an emissions check that utilizes OBDII -- but the reporting capabilities are quite impressive.


Title: Re: MS or other ECUs and the OBDII port
Post by: Chrisbee on August 24, 2015, 06:02:41 AM
I can't speak for all aftermarket ECUs, but it's pretty simple to make the Hydra talk to your OBDII port if your Hydra is CANbus equipped (I think all of the 2.7 units are). I've done this and have a ScanGauge connected to my OBDII port. The ScanGauge is mounted out of the way above my rear view mirror and gives me four additional digital gauges that I can easily customize to my current situation. Normally I monitor coolant temperature, voltage, air temperature, and also display corrected speed in km/hr. With the Hydra, the ScanGauge will even report boost, which is not possible with the factory ECU. The ScanGauge also has some extended X-Gauge parameters you can program in that are handy for track events (e.g., tell tale displays for maximum RPM, maximum coolant temperature and such). It is very handy and getting it all working only involved some quick configuration in the Nemesis software and running two wires from the Hydra to the OBDII port. Needless to say, you can't pull DTCs from the Hydra, nor will it allow you to pass an emissions check that utilizes OBDII -- but the reporting capabilities are quite impressive.
I would be very interested in all the details for getting this kinda thing set up with my Hydra 2.7! If you have the information, or can provide the source for this information, that would be awesome!


Title: Re: MS or other ECUs and the OBDII port
Post by: rstange1 on August 24, 2015, 01:20:47 PM
I would be very interested in all the details for getting this kinda thing set up with my Hydra 2.7! If you have the information, or can provide the source for this information, that would be awesome!
I'd be happy to do that. I'll gather my notes and create a new post in the FAQ and How To section -- hopefully this evening. Stay tuned...


Title: Re: MS or other ECUs and the OBDII port
Post by: rotorglow on August 24, 2015, 01:45:52 PM
Hydra 2.7 boxes are CANbus *capable* but you need to buy the feature to enable it.


Title: Re: MS or other ECUs and the OBDII port
Post by: Reverant on August 24, 2015, 02:02:14 PM
The V5.0+ Enhanced MS2s have an OBD-II output.

You can also add OBD-II to an MS2/MS3 ECU with the CAN bus module from TrackSpeed Engineering: http://www.trackspeedengineering.com/Engine-Management/MSLabs-CAN-Wideband-Module.html


Title: Re: MS or other ECUs and the OBDII port
Post by: ECEng on August 24, 2015, 02:36:25 PM
Thanks for all the fast replies!  A lot of good info and different routes to take.

Since I was originally looking at an MS unit, could you answer a question for me Reverent? Or anyone else that may have knowledge on this.  Data loggers like the AiM Solo uses the CAN bus and I hear they require you to select a vehicle with the logger, I assume this is for the decryption of CAN signals (from hex signals to something the logger can make sense of).  However, if you are now routing everything through something like the V5 MS2s, does the new ECU change the signal encryption or modify them in a way that won't be recognized by a data logger?  Will the data logger, set to a MSM, still be able to read all the data such as wheel speeds, steering wheel angle, accelerometers, etc?

If I'm misunderstanding something or missing something about how the CAN  bus is handled in these cars, please let me know.  All my experience with CAN is with brand new cars, where I am already given a file that encrypts the hex data.  The vehicles I test also are fully loaded with some the latest features and modules...  I've never looked into a vehicle built in 04 or earlier.


Title: Re: MS or other ECUs and the OBDII port
Post by: rstange1 on August 24, 2015, 02:47:44 PM
Hydra 2.7 boxes are CANbus *capable* but you need to buy the feature to enable it.

I believe this was the case when Hydra originally released CANbus interface back in 2011. However, The Hydra 2.7 I purchased from Flyin' Miata in September 2014 had CANbus enabled out of the box at no extra charge. 


Title: Re: MS or other ECUs and the OBDII port
Post by: ECEng on August 24, 2015, 02:53:55 PM
Well I did a little more reading online and noted several sources saying the OBD2 in pre 2005 miatas only have a 1hz refresh rate.  Okay for diagnostics, but any sort of data logging with the CAN bus is rendered useless.

Can anyone confirm this for the mazdaspeeds?  I know the bus talks way faster than that, ABS needs it, so I wonder why the output on the port is limited to 1hz instead of something like a 500hz rate?


Title: Re: MS or other ECUs and the OBDII port
Post by: Reverant on August 24, 2015, 03:11:29 PM
Thanks for all the fast replies!  A lot of good info and different routes to take.

Since I was originally looking at an MS unit, could you answer a question for me Reverent? Or anyone else that may have knowledge on this.  Data loggers like the AiM Solo uses the CAN bus and I hear they require you to select a vehicle with the logger, I assume this is for the decryption of CAN signals (from hex signals to something the logger can make sense of).  However, if you are now routing everything through something like the V5 MS2s, does the new ECU change the signal encryption or modify them in a way that won't be recognized by a data logger?  Will the data logger, set to a MSM, still be able to read all the data such as wheel speeds, steering wheel angle, accelerometers, etc?

If I'm misunderstanding something or missing something about how the CAN  bus is handled in these cars, please let me know.  All my experience with CAN is with brand new cars, where I am already given a file that encrypts the hex data.  The vehicles I test also are fully loaded with some the latest features and modules...  I've never looked into a vehicle built in 04 or earlier.

I know the AiM MXL, MXL2, MXG natively supported the MS2 and MS3 ECUs without the needs for a module; the module is only needed if you want to communicate through the OBD-II protocol (ie you want to use a ScanGauge or the Torque app on your phone)


Title: Re: MS or other ECUs and the OBDII port
Post by: Reverant on August 24, 2015, 03:13:48 PM
Well I did a little more reading online and noted several sources saying the OBD2 in pre 2005 miatas only have a 1hz refresh rate.  Okay for diagnostics, but any sort of data logging with the CAN bus is rendered useless.

Can anyone confirm this for the mazdaspeeds?  I know the bus talks way faster than that, ABS needs it, so I wonder why the output on the port is limited to 1hz instead of something like a 500hz rate?

The stock OBD-II port uses a single wire at 10.4KBps for comms, this is very slow. The module uses a 2-wire 500KBps CAN format, that is much, much faster.


Title: Re: MS or other ECUs and the OBDII port
Post by: rotorglow on August 24, 2015, 03:19:38 PM
Hydra 2.7 boxes are CANbus *capable* but you need to buy the feature to enable it.

I believe this was the case when Hydra originally released CANbus interface back in 2011. However, The Hydra 2.7 I purchased from Flyin' Miata in September 2014 had CANbus enabled out of the box at no extra charge. 

Could be, but there's no info on the website about it (either way).  They were having periodic discounts on CAN bus and FlexFuel add-ons as late as 2012 and 2013 after I got mine, and some of those features may be wrapped into the higher versions of the box (above the typical Gamma), so the extra cost might have been hidden in the cost of a higher level.  

Just dropped them a line to get the scoop for sure.


Title: Re: MS or other ECUs and the OBDII port
Post by: '95MSM on August 24, 2015, 06:57:27 PM
...  I know the bus talks way faster than that, ABS needs it, so I wonder why the output on the port is limited to 1hz instead of something like a 500hz rate?

The MSM ABS module is self-contained. It does send status codes or something similar to the ECU, but it functions on its own. Hyde dropped an MSM ABS system into 90MSM and I'm pretty sure it doesn't talk to his Adaptronic ECU, or if it does it isn't meaninrul.

I don't think there is any sort of bus on an MSM.


Title: Re: MS or other ECUs and the OBDII port
Post by: ECEng on August 25, 2015, 01:19:49 AM
...  I know the bus talks way faster than that, ABS needs it, so I wonder why the output on the port is limited to 1hz instead of something like a 500hz rate?

The MSM ABS module is self-contained. It does send status codes or something similar to the ECU, but it functions on its own. Hyde dropped an MSM ABS system into 90MSM and I'm pretty sure it doesn't talk to his Adaptronic ECU, or if it does it isn't meaninrul.

I don't think there is any sort of bus on an MSM.

Huh, well that's interesting.  I guess that is one way to deal with it if there are no other modules on the CAN bus.  The "early" days of obd, CAN, and things electronically controlled. 


Title: Re: MS or other ECUs and the OBDII port
Post by: rotorglow on August 29, 2015, 07:53:35 PM
Just dropped them a line to get the scoop for sure.

Closing the loop on this, I heard back from Jeremy yesterday.  CAN hardware is on Hydra 2.7 boxes after approx. April 2012.  CAN feature is included free on current boxes, still $150 for some of the rest of us to enable the built-in hardware, cutoff date unspecified. 

A little disappointing, but not terribly surprising, given way Hydra handles things.