Problems and their solutions for CNG Vehicles

Daihatsu Charade operates with a 1,000cc engine displacement, and a 50L cylinder should get you around 120km with AC. You mileage should be worst, maybe lacking in power as well.


As per you brief explanation, we suspect that you may NOT have a CNG mixer. Since you are using electronic-landi renzo CNG kit, you may see that you have a hose connect directly from the CNG regulator into the airfilter. Perhaps, you do not have mixer between the carburetor and the airfilter casing.

In modern electronic CNG kit, you must have a CNG Mixer. It works as a Husband & wife team, that is CNG regulator must have a CNG Mixer. In the past peumatic CNG regulator does not need a Mixer as it has a special connecting vaccum hose to control gas flow. An 'universal pipe' is installed into the airfilter to introduce CNG into your carburetor.

But in modern electronic CNG kit, universal pipe is NOT effective as it require alot of Engine Vacuum to operate in. Thus, you need to open your Power Screw (screw attached between the mixer & airfilter) at maximum. Having open the Power Screw maximum, you will only be able to control the Landi Renzo's gas flow diaphragm.


'Universal Pipe with electronic CNG regulator' has the following generic problems:
(a) Time Lag in Pedal & Engine Response;
(b) Difficult to tune for idling;
(c) Poor idling (unless with patient tuning);
(d) High consumption of CNG gas;
(e) Strong unburnt gas smell at exhaust; and/or
(f) No power at climbing hills.

(Continuous Tuning needed to improve mileage, but it will be off again in a couple of weeks).

Thus, please check your vehicle whether you have a CNG mixer installed. If not, please have it installed. With mixer, you should notice the following:
(a) Improve engine response & pedal pressing;
(b) stable idling
(c) easy to obtain optimal idling
(d) lower consumption of CNG gas (better mileage)
(e) More power to climb hills.

(Tuning leads to stable idling for months, until airfilter get dirty.)


A universal pipe problem is common in Malaysia as well. Only one company in Malaysia can design CNG Mixer at www.ngv.com.my.