New install, sensor not heating and outputting 2.5V

Hi Chaps. I’m running a rover v8 on megasquirt, using a spartan 2 and lsu supplied by you guys. The purchase was a long time ago now, but kids and covid conspired to make the project much slower than intended!

I’ve just got to the point of the engine idling, however I’m having issues with my AFR readout, so struggling to proceed with tuning with confidence. I’ve done the linear calibration exercise which didn’t require much tweaking and the initial two test voltages look good. However, after this point I get 2.5V or 15AFR constantly. This doesn’t change when I change the fueling. I also get this result for the air test. After around 5 min of the air test I couldn’t feel any temp rise in the outer LSU or exhaust (that part of the downpipe was taken off the manifold for the air test).

So I’m thinking its either a dodgy LSU or a bad earth? At the moment the white heater ground is wired to the same chassis point as my relays. LED output is also earthed here.

My black sensor ground us wired to the megasquirt sensor ground. I think this might be my mistake. Should I wire this to the engine block where the four main grounds from the megasquirt go?

Just gone back to the megasquirt manual, which does show the lambda sensor wired to the megasquirt sensor wire. So I believe its wired up ok.

I’m a bit stumped. Any ideas anyone?

The customer was sent a replacement controller.