That wrapped wire sense the engine running. Try a diy. Start the car on CNG and the remove that wire away from coil cable. The cng kit should trip in a few seconds. If it doesn't, its not working properly.
Actually if you turn the key to ignition the cng kit gets operational and if you do not crank then after a while the kits main valve closes just to stop the gas from leaking out the air filter.
I hope you got it.