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Discussion Starter #1
Does anyone know where I can easily tap into the CAN bus for a data acquisition system in a 2005 Lotus Elise?

I'm hoping I can find a port so I don't have to splice. Any idea if there are any CAN connections on the ODB-II port?

Thanks,
Chris
 

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I have a communication from Lotus in the UK confirming 2008.
Until 08 they use a Lotus specific version of CAN that current OBD readers do not understand.
The ECU currently communicates to the gauge cluster via CAN.
Search posts from charliex, there is info out there on how to talk to Lotus CAN, but as far as I know, no off the shelf tools for it.
 

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Until 08 they use a Lotus specific version of CAN that current OBD readers do not understand.
The ECU currently communicates to the gauge cluster via CAN.
Search posts from charliex, there is info out there on how to talk to Lotus CAN, but as far as I know, no off the shelf tools for it.
I'm also not sure that pre '08 cars have any ODB-II type of data on the CANbus. Yes, the instruments are connected via CANbus, but if the need is for "performance data", it may simply not be there... But that's just a guess on my part...
 

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Discussion Starter #8
CAN

I'm just looking for RPM and TPS to get from the ECU into my AIM Micron XG Log dash.

I'm going to get Lat/Long G's and steering from external sensors.

Pat Salerno has said he's done it, but at the time I didn't inquire into it. Anyone know how to get in touch with Pat?

Thanks,
Chris
 

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TPS: tap into the TP sensor signal wire (green/yellow). You should check the voltage difference between the TP sensor ground wire (black) to the datalogger analog ground to see if there is any offset, but I would not wire the analog ground to the TP sensor ground as there should be no offset and in this case tieing the grounds will create problems.

RPM: if the engine harness does not provide a loop for timing reference (I don't think it does - my engine harness is long gone so can't tell for sure) then use an ECU ignition coil output for the rpm reference (wires are all red/something). As long as the datalogger has a decent input impedance (it should) then no problems. Just check for hot coils once you first wire it up in case one gets grounded.
 

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i don't quite understand, pennsylvania inspection requires plug into the OBD connector for a readout of some sort.
is that just that, that much of the installed software works but no realtime info is available on the (mine) 06 elise?
just curious.
sam
 

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For a 2005, 2006 & 2007 an OBD II reader ISO9141 is used, the 2008 uses CAN.
i don't quite understand, pennsylvania inspection requires plug into the OBD connector for a readout of some sort.
is that just that, that much of the installed software works but no realtime info is available on the (mine) 06 elise?
just curious.
sam
 

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all elise/exige have CAN at the OBDII port, pins 6,14. Only 2008 actually runs the OBDII info over CAN (ISO 15765-4). 2005-2007 has cluster info over the CAN: speed, tech, MIL,shift light,gas, temp,oil light
 

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If someone were to buy one of the Elm327 chipset readers (bluetooth) what sample rate would we get from the ISO9141 if we wanted to monitor 3-5 PIDS in real time on an 06 model year? Is 5hz possible? Is there an Elm based reader that can tap into the CAN side at 1mb/s?
 

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If someone were to buy one of the Elm327 chipset readers (bluetooth) what sample rate would we get from the ISO9141 if we wanted to monitor 3-5 PIDS in real time on an 06 model year? Is 5hz possible? Is there an Elm based reader that can tap into the CAN side at 1mb/s?
If you are looking for a reader you are probably better off not using the elm chip: you would need to build all the peripheral circuitry to get it to work and the chip doesnt support the 1K bitrate over CAN. A for the obd reader you can literally buy a iso9141 reader that will read the PIDs and convert them to rs232 or usb for about 100 bucks.
 

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5hz with 3 -5 PID's isn't that practical, its very slow to respond to requests.

much better going with dstevens approach.
 
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