I have this issue with CNG consumption of my khyber, it does 120Km on full 50L cylinder in lahore city without A/C. I know it should be more than this but if I decrease or even increase the gas flow the engine pick goes bye bye. It is the optimal setting giving me good pick 0-100 in 19sec (CNG) and top speed 135km/h.
The issue is when I get it filled from CNG station and record the reading on the pressure gauge in the engine compartment of the car it shows 210 bars. After few hours of car standing at night the gas/cylinder cools down and shows reading 190bars in the morning.
After travelling just 22Km (35 minutes drive) the remaining pressure in the cylinder falls from 190bar to 120bars (70 bars difference). this 120bar pressure then goes for 100kms with 10bar approx remaining.
there are no leaks in the system , confirmed.
My question is
is it normal?
why is it happening?
can it be rectified and HOW?
thanks in advance.