LC-1 wiring question..

[Redline Motorsports]

I am using only three of the seven wires coming from the LC-1 unit to tie into the FS. The colors are Yellow (Analog 1), White (System ground), and Green (Analog ground). I have both the White and Green tied together.

The Yellow (Analog 1) is connected to the E pin of the external pinout and the other two (White/Green) are connected to pin D.

The black and Red a tied to switched 12 volt power respectively.

I also set up the Log programming software under Anolog 1 to the following settings

.883 volts at 9.99:1
4.216 volts at 19.99:1

I then selected the program button.

I also selected the appropriate PID for {EXT.AD1}

Is the wiring correct? I keep reading about the ground issues and want to confirm this is wired correctly.

Thanks

Howard

[Ira]

I think that the white, system ground, should be tied directly to ground or to the heater ground and not to the FlashScan ground. don't know what the internals look like, but if the inputs ever become isolated like I think they might be in the next version it won't work at all and even if it does, the system gound is not part of the output signal and doesn't belong there. You didn't say which sensor PIDs you chose so I'll assume the voltage levels you chose make sense. I could be wrong, but as I recall the LC1 as shipped has narow band output on analog 1 and wideband output on analog 2.

Ira

[Blacky]

What Ira said, plus...

System ground (white) and analog ground (green) should both be connected to FlashScan pin-D.
On my setup, I connected Analog 1 to flashScan pin-C and Analog 2 to FlashScan pin-E.
Heater ground (blue) should be connected to the vehicle's chassis ground.

See image...

[Ira]

Do you really want the system ground connected to analog ground? If they implemented the thing correctly I would assume that the analog out is referenced to analog ground and there should be essentially no current flowing through those wires other than the load FlashScan put on it. On the other hand I'd assume that system ground is the return for the LC-1's internal 5V supply and might carry a fair amount of current. If that's the case, does it really make sense to tie the white, system ground, to FlashScans analog ground reference?

And as an aside, in FlashScan V2 does the analog ground actually connect to ground?

Ira

[Blacky]

Hi Ira,

Yes, you should connect analog and system ground together.

From the LC-1 install manual:

6. Connect the system ground to where you will use the analog out signals. If you use the analog out signals as input for an ECU or data-logger, connect the system ground to the ground of the ECU or data logger.

Pin D (analog ground) of FlashScan is exactly the same circuit as the ground for FlashScan.

FlashScan Pin D = DB9 Pin 1 and 2 = OBDII Pin 4 and 5 = chassis and signal ground.

Note: Pins 4 and 5 (chassis and signal) ground are tied together on GM OBDII applications.

Regards
Paul

[Redline Motorsports]

Thanks Paul.

Pictures worth a thousand words.

Howard

[bK]

Hi Ira,

Yes, you should connect analog and system ground together.

From the LC-1 install manual:

Pin D (analog ground) of FlashScan is exactly the same circuit as the ground for FlashScan.

FlashScan Pin D = DB9 Pin 1 and 2 = OBDII Pin 4 and 5 = chassis and signal ground.

Note: Pins 4 and 5 (chassis and signal) ground are tied together on GM OBDII applications.

Regards
Paul

Hi Paul,

Not sure if this idea is possible or had been thought of before but seeing Flashscan uses pins 1 and 2 of DB9 connector for ground, could I setup a very short adaptor between OBDII cable's DB9 female connector and the male DB9 connector of the Flashscan?

The DB9 adaptor will be straight thru with a connection point (pins 1 & 2 together) to allow grounding of the LC-1 analogue, system wires and Pin D from the Flashscan so in theory will give me 0V offset between Flashscan and LC-1?

Would this adaptor cause problems with the signal from OBDII interface to the Flashscan?

Cheers,
Brett

[jsttry]

Blacky its a bit late now but where is that a pic of? its late and I can't go out to the car to look but is it under the steering column in the cabin? I've just got my LC-1 back from warranty replacement and want to hook it up in a way that I can easily plug it in and out of cars. was thinking of using the cigarette light for 12v and ground but don't want to run both to the same ground point.

What Ira said, plus...

System ground (white) and analog ground (green) should both be connected to FlashScan pin-D.
On my setup, I connected Analog 1 to flashScan pin-C and Analog 2 to FlashScan pin-E.
Heater ground (blue) should be connected to the vehicle's chassis ground.

See image...

[SSbaby]

Blacky its a bit late now but where is that a pic of? its late and I can't go out to the car to look but is it under the steering column in the cabin? I've just got my LC-1 back from warranty replacement and want to hook it up in a way that I can easily plug it in and out of cars. was thinking of using the cigarette light for 12v and ground but don't want to run both to the same ground point.

I'm using a cigarette plug for my switched 12V. I grounded the LC-1 blue wire to plug's earth wire. Also grounded the white and green wires from LC-1 to Flashscan blackbox, plugged the analogue brown LC-1 wire into the Flashscan blackbox C-terminal and not using the yellow wire at all... but getting weird AFRs... like 21.7!!!

I've checked the respective voltages between points (power - earth, etc...) and all seems fine with the way I hooked up the connections, which I followed as per LC-1 and EFILive installation instructions.

Also used the Logworks serial connection to log AFRs... still no luck. I've read the various threads on this forum regarding possible earth wire issues so I want to know from people how they've managed to overcome their early problems relating to high AFRs on their logs?

[Blacky]

I'm using a cigarette plug for my switched 12V. I grounded the LC-1 blue wire to plug's earth wire. Also grounded the white and green wires from LC-1 to Flashscan blackbox, plugged the analogue brown LC-1 wire into the Flashscan blackbox C-terminal and not using the yellow wire at all... but getting weird AFRs... like 21.7!!!

If you have a multimeter, then temporarily reconfigure the LC-1 so that the analog output is set to a flat, horizontal line at a specific voltage. i.e. set 10AFR=4V and 20AFR=4V. That will cause the LC-1 to output 4 volts all the time. Use the multimeter to check that there is 4 volts between analog 1 or 2 (whichever you configured) and analog ground.
If that checks out, plug it into FlashScan and check the PID: {EXT.AD1} or {EXT.AD2} (whichever you connected it to) to see if FlashScan reads 4 volts also.

Regards
Paul