Home made 1.3U cable

User topics relating to hardware that interfaces PCs to ECUs

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Home made 1.3U cable

Postby Wipster » Thu Apr 14, 2011 9:14 am

Hi all,

I have just knocked together a 1.3U cable on my breadboard and flashed in the settings from a tactrix one so the line inversions are the same but I cant get a contact with the ECU in my car. It never connects after waiting for INIT in evoscan ecuflash mitsulogger and mutmonitor so something is a lil wrong.
I used the circuit diagram with modifications like so http://yfrog.com/15openport1j taking out the subaru bits.
Also I modified the OBD2 header ports to match that of my car which has the same physical hardware as an evo4, do I need to connect the L line to the debug pin1? I have tried it but it doesn't seem to help I see various places saying leave it grounded to get into debug and only connect K, Ground and VCC.
Is there a length issue with these lines? I have the obd connecting to a 1.4m serial cable with my converter hardware at the end to get the serial to usb... is it worth me putting the K&L line conversion right up in the connector?

Thanks, I realise this is a bit of a ramble but any suggestions would be appreciated as I have rewired it about 3 times now.
Wipster
 
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Re: Home made 1.3U cable

Postby Wipster » Thu Apr 14, 2011 3:06 pm

Here is a picture of my waveform at the end of the cable if I stream random data at it at 10kB/s. There is a bit of a lag on the rising edge but I think I am within spec... http://img130.imageshack.us/i/img0056qc.jpg/
Wipster
 
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Joined: Mon Mar 28, 2011 4:59 am

Re: Home made 1.3U cable

Postby Wipster » Mon Apr 25, 2011 2:38 pm

Well I got it working, I removed the multiplexer and just implemented the K line with pin 1 of the obd port grounded to enter debug mode.
It seems to log fine however I cant get the ecu map off, not entirely sure which option I should select in the 'read ecu' menu or if I need to specify something else manually.
Every option I try ends with ecuflash telling me 'unable to connect to vehicle interface.' I have tried 1.29a but that has even less options in the reading menu...
Wipster
 
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Joined: Mon Mar 28, 2011 4:59 am

Re: Home made 1.3U cable

Postby radsdau » Wed Apr 27, 2011 9:39 pm

That schematic doesn't seem to have the voltage multiplier circuitry required for Mitsubishi that should generate 15-18Vdc.
Check if there's a later 'Universal' schematic around.
radsdau
 
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