Very weird Serial Issue

[Highlander]

Hello guys, this is my issue..

I have an LM1 which is my workhorse to tune. It has done a TERRIFIC job.

Now to the problem... I have my cable that works flawlessly to interface serial from the LM1 to the V2. Well. Since i have the LM1 on my car and leave it there unless I need to tune a customer's vehicle it was working fine...

So... I use the LM1 connected to the external power supply provided by Innovate that plugs in to the 110v regular electric outlet. Well... to my surprise I was having issues a couple of weeks ago and I thought it was the cable. I remade the cable and all was working fine after a failed attempt at the dyno. So I was testing it on my car and nice.... ok...

Now... I do not get serial data to show up (or the serial led blink) while its connected to the external power. Only when its connected to the CIG lighter of the vehicle...

Is this because of the 14v I get outside vs the 12v from the car? This almost made me pull my hair out and expel every single customer from the dyno last night when I had a Z06 to tune that is from one of my most important customers (if not the most) and I wanted his car to be PERFECT! So the only different thing was that I was using the internal cig lighter power cord and Voila, when I saw that led blink I was like.. .WHEW.... I am getting addicted to this efilive thing.

Paul any insight?

Thanks

[joecar]

Where is your PC/laptop powered from...?

[Highlander]

wall outlet.

[joecar]

When you power your LM-1 from the wall output (via transformer), you are isolating its ground from FlashScan V2 (which is grounded via the vehicle's OBD-II connector) and from your PC/laptop...

i.e. the LM-1's ground potential is at a different level than V2's (and vehicle's)...

so the serial data signal's voltage relative to serial data ground is wrong (too high or too low) for the serial data signal to be recognized.

My $0.02 guess.

[Highlander]

Probably... but it was working fine a couple of weeks ago!