TT_Vert

iTrader: (12)

Well i set my lc1 output to a linear .5V and this is what im getting. Its all over the place. At 5.0V I get a steady 4.917V w/ an occasional switch to 4.922V but .5 V is all over the board as is 2.45V. Anyone have any ideas? This POS is frustrating me.. This is in a c5 vette FWIW.

Raw Voltage V
0.522
0.601
0.64
0.547
0.522
0.63
0.679
0.591
0.63
0.625
0.654
0.527
0.596
0.688
0.581
0.605
0.684
0.728
0.664
0.566
0.654
0.684
0.747
0.557
0.693
0.742
0.732
0.625
0.698
0.62
0.557
0.601
0.664
0.615
0.61
0.64
0.718
0.688
0.61
0.654
0.571
0.518
0.659
0.635
0.645
0.552
0.635
0.645
0.552
0.62
0.693
0.605
0.547
0.635
0.732
0.615
0.586
0.61
0.664
0.649
0.532
0.771
0.659
0.518
0.62
0.63
0.605
0.562
0.635
0.742
0.64
0.63
0.605
0.635
0.557
0.591
0.693
0.645
0.488
0.625
0.64
0.63
0.562
0.693
0.601
0.62
0.591
0.703
0.669
0.513
0.601
0.62
0.62
0.547
0.61
0.679
0.684
0.547
0.742
0.703
0.62
0.576
0.664
0.64
0.62
0.625
0.596
0.537
0.532
0.723
0.693
0.576
0.596
0.654
0.552
0.537
0.615
0.674
0.601
0.557
0.703
0.664
0.566
0.586
0.669
0.571
0.664
0.625
0.713
0.698
0.586
0.645
0.684
0.591
0.552
0.62
0.596
0.586
0.635
0.664
0.605
0.557
0.591
0.635
0.659
0.615
0.645
0.654
0.586
0.645
0.679
0.635
0.571
0.596
0.732
0.581
0.557
0.635
0.61
0.61
0.527
0.713
0.63
0.552
0.601
0.659
0.571
0.513
0.654
0.635
0.591
0.586
0.596
0.698
0.527
0.527
0.723
0.615

muncie21

iTrader: (14)

Where did you connect your grounds to?

TT_Vert

iTrader: (12)

Its a vette so I have very few to get at. I took a ground off the ECM if I recall correctly. Do you think the problem lies in my wiring? It does this for all voltages EXCEPT 5V which is steady at 4.917V. And I have all 3 grounds going to the same spot too, I read this may not be a wise idea but its VERY hard to find a chassis ground on a plastic car lol.. After rereading the manual it says
"the blue, white and green wires should all be grounded to the same ground source and although these grounds are of the same source , the BLUE wire should be wired separately from the white and green wires to avoid analog noise."

WTF? wired together but separately?

Dave

xssive

iTrader: (123)

That just means dont stack ring terminals on top of eachother. You need to ground them to the same source , but not ontop of one another

PurplePiss

Run the blue wire into the engine compartment and ground it to the front of the passenger head.

TT_Vert

iTrader: (12)

how bout the batterY? it would be easier. Thats going to look like crap. YOu think thats the problem? A ground?? I guess i can text that theory and run a temp ground to neg of battery.

Dave

muncie21

iTrader: (14)

I have the LC-1 on my vette. Basically, I used the old O2 harness to wire up the WB. Then I ran the 0-5V DC signal wire from the WB to inside the car. I grounded the signal wire to the EIO of HPT. Also, the LED and calibration wire are connected to a ground near the radio.

In short, heater ground is separate from signal, which is also separate from calibration. BTW, I use the WB to simulate NB signal also...works great.

TT_Vert

iTrader: (12)

old o2 harness? I put a bung in. So you used a ground from the EIO to the signal wire? What wire is the "signal" wire? Do you have the other 2 grounds together at the radio?
Dave

muncie21

iTrader: (14)

If my memory serves me correctly, there are 4 grounds (if you use the NB simulation also) on the LC-1.
1) Heater- This I tapped from stock location (original wiring harness)
2) NB- This also is provided by the original harness.
3) Signal- (0-5V DC signal for HPT) this is grounded to the EIO
4) Calibration- mounted LED and push button in ashtray and connected ground near radio.

If you are using a bung, then you'll need switched 12VDC and engine ground (for the heater). Run the signal (positive and negative) from the LC-1 into the cabin and connect to EIO. Calibration is optional.

Best of Luck

TT_Vert

iTrader: (12)

which one is signal negative? system or analog ground?

Dave

joecar

Either one will work as signal ground.

TAQuickness

iTrader: (28)

my lc1's didn't like drawing power or ground from the stock o2 sensor bungs (PCM supplied). I ended up running a direct connection to the battery for power and used the rear o2 power/ground to drive a relay for proper on/off switching for the lc1. LC1 ground is chassis ground.

Teutonic Speedracer

iTrader: (20)

I ran a ground directly from the batter/chassis ground to a terminal block behind the dash. Then I attached the autometer gauges, LC-1, etc. to individual terminals on the terminal block which has that nice SOLID 12 gauge? wire running to the same ground on the inner fender that the battery goes to. Seems to work well.

TT_Vert

iTrader: (12)

you lost me now
dave

joecar

Dave,
Either analog ground (green) or system ground (white) can be used as the "signal negative"; they are internally connected;

this is how I connected mine (includes NBO2 simulation):

svede1212

iTrader: (3)

from what i understand the engine block NOT the battery is the true ground of the car as the alternator is the reference point. run your grounds to the block with the blue wire attached seperately.

TT_Vert

iTrader: (12)

what do u mean attached separately?
Dave

cantdrv65

iTrader: (3)

The engine block and battery negative are electrically equal....they are connected together. You can look at them as the same point.
__________________

GuitsBoy

iTrader: (4)

Technically, even that short run of cable ground cable between the block and battery would have some resistance, and therefore create atleast some differential.

cantdrv65

iTrader: (3)

Not enough that you'll see it when using 12Vs....You wont see the resistance difference to three decimal places on an VOM either.