Syvecs Forums

Has anyone previously used the 0-5v output from an LC-1 controller to feed the syvecs a wideband signal? I have tried to do this and have used an AV input to do so. This is working however it reads approx 1volt lower than what the LC-1 is outputting. This results in the afr reading roughly 2 points richer than what my gauge says (and I trust the gauge). I think the problem is where I'm grounding things. I'm grounding the LC-1 heater to chassis and the 'system' ground to the same point, I was grounding the LC-1 analogue ground to chassis aswell but I tried ground this to the analogue ground on the syvecs and it is still reading wrong.

One thing I don't know is whether the LC-1 needs a pull up or if it supplied its own on its output. I have set up the LC-1 for a 0-5v output and I can see this when I meter it at the back of the input pin on the syvecs. Am I perhaps using the wrong input from the syvecs?

What pin are you wiring it to on the syvecs? Are you sure the 0-5v output is configured correctly? There shouldn't be a problem. Are you using a serial fed gauge?

Ultimately it doesn't matter as you can adjust the syvecs linearisation to match what you believe to be the correct AFR.

I'm using pin 42 (off the top of my head), it's one of the AV inputs and is configured for 5v and I have used a linearisation I found on this board for the LC-1 which matched up perfectly with what my gauge tells me at various voltages. The gauge is fed from analogue output 1 from the LC-1 controller and the syvecs is fed from analogue output 2 which has been programmed to output 0-5v (1&2 are now identical).

The setup did work fine the first time I hooked it up, this was for about 20-30mins of tinkering but then when i restarted the car sometime later that evening the indicated voltage being seen was now consistently down approx 0.9-1volt. When I measure from the input pin to ground (with the LC-1 disconnected) I get the same approx 0.9volts. It's almost like the LC-1 is having to overcome this potential before it registers its own signal. Could this be dodgy ground offset?

I think we figured this out. Turns out the ECU was not grounded properly and everything was off. Vbat was off as was the map sensor. We grounded a power ground to the old ecu bracket and everything is reading normal, wherever the syvecs was grounded before (loom im presuming) had some sort of impedance.