FLM911

Thanks Peter

Fuel did not come across I think everything else was there for OBD. Sent you a PM.

orthojoe

Peter, do we have confirmation that the CANbus protocol for the 991 ECU is compatible with the 991 GT3? That would mean that the ECU between a regular 911 and the GT3 are the same. This would be nice for the guys taking delivery now not having to wait until AiM cracks the GT3 ECU protocol.

ProCoach

Unlike the 997.2 GT3, which retained the Bosch ECU and an entirely different (older and more limited in channels and throughput) management CANBus from the street cars newer (many more channels, much quicker sample and refresh rate) Siemens 3.1 ECU, the ECU in the 991 shares the same basic protocol with its GT3 variant.

As in the past, the diagnostic plug connection is only for static tests and OBD-II testing requiring less info and supplied at a rate slower than needed for good analysis, whereas tapping into the vehicle engine management-instrument cluster CANBus provides more channels and supplied at a much faster refresh rate.

We'll see when Richard and/or Matt let me piggyback the AIM connection onto their twisted-pairs, but this has been tested and released by AIM.

ProCoach

Richard, Matt, et al,

It is ALWAYS possible to wire to the backside of the J1979 (OBD-II) connector with an unterminated CAN cable, use the 991_981 OBD-II protocol and run the lead behind the carpet out of your way.

You could make up and/or install a harness like Jerry's or unterminate your existing OBD-II plug, too. I think if you're going to go to that trouble, I'd rather get more and quicker sampled information just going to the CAN of the car.

After hundreds of CAN installs on 997.1 and 997.2 GT3 and GT3RS cars without trouble, it's not a hack to do the same to 991 and 991 GT3 cars...

FLM911

Just going to go with the CAN connection instead, be easier and safer than mucking about with the OBDII.

Do think the new OBD location means no data loggers will practically be able to connect using that port and will have to go via a splice into the CAN

orthojoe

Great! Thanks for the info. I know what to do with my extra CAN harness now!

ProCoach

Yes, considering most logger's OBD-II plugs are more bulky than the right-angle AiM. That includes the MoTeC CDL3 and C125. I don't know how you're going to to an R-K connector...

The Racelogic/VVBox is CAN-only anyway, IIRC.

BlueJay73

Do you solder your connections?
I'm asking because I just want to know that applying an electric soldering iron to the ECU wires doesn't introduce currents that can screw up the car's computers, electronics, etc.
If you solder the connections w/o issues, then that's good enough for me.
Thanks

orthojoe

I soldered the connections to my ECU over a year ago on my boxster spyder, and haven't had a single problem or issue. Make sure the car battery is disconnected and that you ground to the actual chassis itself, and you'll be good.

ProCoach

I have always soldered the connections and never had an adverse event.

BlueJay73

Thanks guys.
All I needed to know.

BlueJay73

OK, this seemed too easy.
My ECU wires in my 2011 C2S are supposed to be black/white and yellow/white twisted pairs. Trouble is, I found TWO twisted pairs of those color wires in the same wire harness bundle. They look identical.
Any ideas, anybody?

ProCoach

Hmmm. I remember only one. Post a pic, but the twisted pair you want goes from the ECU to the back of the instrument cluster. I use the area next to the fuse box to access the harness. Will post pics later today.

BlueJay73

I'll take a picture and email it to you.
I hate to admit it, but I do not know how to attach a picture in a post.
I'm kind of thinking the two twisted pairs are actually the same pair. They just made a loop or something. They are identical.
Thanks for your response.

ProCoach

No sweat. Glad to help in any way. These things are GREAT tools!