2010 WR250X without OEM speedo

After my OEM meter unit broke (I got the speed multiplied by 3 fault) I thought to replace it by a vapor unit. I took that decision for two reasons : for 1 I see the above fault in the speedo unit, so I didn't want to replace a faulty unit with another at a 350€ cost, which would possibly show the same fault after disconnecting the battery. For 2 I liked the rev option of the Vapor and additional features.

I thought to go with the additional unit which provides 4 leds for, in my case, turn signal, head light, fuel warning and neutral light.

After removing the oem unit and installing the Vapor I face now one major and two minor issues :

the minor issues are that the fuel warning and neutral light deliver only mV values, not the required 12V to make the leds of the vapor add-on work. Signal and head light leds work well.

the major issue is that the bike would start the engine and idle ok, but would not accept the throttle to raise the rpms, in which case the engine will stall each time.

Now I read that some say the WRX won't work without the OEM unit, others say it would work just fine. What could be the issue for the bike not to accept any throttle ?

Also any ideas how to overcome the mV issue on the fuel and neutral light ?

Note to self & others : the major issue was a "no issue" - fuel line pinched when mounting the tank.

I'm still looking for a solution to get the fuel warning and neutral indicator work with a 12V warning light.

Thanks for the follow up!

The stock unit should/could be calibrated "back" with a speedo healer.
I've seen it mentioned as a solution elsewhere.