CNG cars have received bad press but most of the so-called problems can be put down to the popular assumption that a factory fitted kit devolves the owner of all other responsibilities.

cng car maintenance tips

Wrong. Cars are designed to run on petrol, so it takes a bit of caution and care to keep your CNG car healthy. Here’s how:

Start driving on petrol

Start your car on petrol and let it idle for a bit. Don’t switch to CNG — even if your kit allows you to —  for at least one kilometre. This helps lubricate the engine, and reduce wear-and-tear.

You may also be interested in these stories

LPG vs. CNG – which is better?

Pros and Cons of installing CNG in petrol AT cars

Five points to consider when installing a CNG kit

Service frequently

Perishable parts such as air filters take a beating on CNG, so service your vehicle more frequently; if your service is due at 15,000 km, get it done when you touch the 12,000km mark. This will spare you the horror of being stranded on a rainy night due to simple issues like lack of engine oil, coolant or a breakdown of parts.

Get CNG tuning done by a specialist

Always get the CNG kit tuned by a specialist. If your car has a factory fitted CNG kit,  go to the authorized service center. At the hands of unqualified mechanics, your CNG car could have problems like increased engine vibration, irregular acceleration (missing), etc.

Replace spark plugs

Spark plugs meant for petrol vehicles wear out fast when driving on CNG. There are two ways you can combat this issue: either use special spark plugs meant for CNG cars (they cost between Rs.150-200 a piece) or you could request your mechanic to reduce the gap between the metallic tip of your plug and the actual source of spark (This will cost you nothing if you know the guy!)

Never drive till tank is empty

The CNG cylinder’s pressure falls as it empties, and can cause the valve to explode. Also, replace the valves regularly — it will cost you anywhere between Rs.200-Rs.350 depending on your kit.

Here are some additional tips from the CarToq Community!

 

Manmeet Singh: To increase your pickup in CNG you can get pickup booster which will cost you around 1k but it will increase your car pickup up to 60%. Any CNG fitter will provide with you this booster but make sure it’s organized (sector) because it is available in China also :)

 

Ankit Bansal: These pickup boosters increase the pickup but the average of the car is gone

 

Ankit Bansal: Always start your car on petrol mode during cold starting, drive for 2,3 km then change to CNG mode…Also get your vehicle serviced from authorized service stations only, and at regular intervals

 

Abhi Jeet Anything you do, CNG is going to beat the hell out of the engine as it is a gas which just runs through pistons and block, and just passes away. In this case, the pistons and block are not wet, which leads the water to enter the block, ruining the casket. Petrol and diesel remain in pistons till the next pressure of fuel is not absorbed by engine. The only way to increase the life of engine is to fit an iron head casket which makes the engine live 6-7 months.

 

Abhi Jeet: After two years, change your engine

 

Jojo Singh You can clean the air filter once a week yourself.

 

Jojo Singh: I don’t start my car (a carb one) on petrol because tuning is a major problem when shifting fuels

 

Rishabh P Nair: Jotivinder do you have an old kit? The old ones used to have a knob on the side which can be turned to tune the car. That’s essentially all u need to do. Keep turning it and see if the engine keeps running. Once you get that done, just try the same thing with the AC turned on :)

Follow these tips, and your car will never trouble you and you won’t need to join the bandwagon crying foul about the kit killing cars.

Also see below:

Breakeven point: How many kms a day justify CNG or LPG conversion? 

CNG vs LPG: How to decide!

 

25 COMMENTS

  1. This is a very good article. I don’t think that CNG ruins the engine. If you add 1% 2T oil to petrol and drive10 % of your daily running on Petrol, I am sure the car will have no lubrication related woes. Cleaning the air filter once a week surely helps.

  2. @ Mr Shreyans, Don’t you think that the throttle body needs cleaning in case of LPG not CNG since the latter is Natural gas. Pl clarify. Thanks

  3. Well, it is still an organic fuel at the end of the day. Plus, it is my experience with my CNG WagonR that if the throttle body is not cleaned regularly, idling rpm becomes erratic and the responsiveness reduces. And then, the kit cant be set properly if the throttle body or injectors are clogged. This is a best practice which keeps the car performing optimally over time.

  4. The points you make here are equally applicable to cars running on Petrol, or for that matter, Diesel. Internal Combustion Engines, in general, survive better when you follow this list of stuff, irrespective of the fuel they use. For e.g.: (1) Starting on petrol / driving for 1km, or just idling the car at startup till the engine gets to its ideal operating temp (engine temp needle touches “C”) reduces wear and tear, CNG or no CNG. I’ve been doing it for years, and the best way to do it is get in, start the car, idle it while you do your pre-drive checks like mirrors, radio station selection, set up your water bottles, clean your spectacle and whatever else you do trying to drive that first Km each day. Best do all this while the car is stationary, and idling. (2) Follow a simple 90 day tune up cycle: Take it to your gas guy, tune the kit, set the spark plug cap, clean the filter. I’ve been doing that for 2 years… six trips so far in two years actually, and there have been no problems whatsoever. Not even so much as a mis-start in the morning. I haven’t had any experience with excessive spark plug wear so far, still get them changed every 25,000 km, or more if they’re still healthy. Got them done once so far in 2 years, and the car has done 50,000 kms on CNG so far (200,000+ kms overall); still manage 20 km per kg of CNG in city (17 in Mumbai city, more in the outskirts), 24+ consistently on the highway. No sparkplug wear so far. (3) Follow a six monthly service cycle: car wash, oil / fluid levels check, tune up, followed by a trip to the gas guy for the gas tune up.

  5. These steps amount of “preemptive maintenance”, so you don’t have problems, and they’re true for all cars, irrespective of the fuel they run. However, I did notice that if you run full-tank to full-tank on CNG, you do get better mileage than filling odd measures of, say “Rs. 200” or Rs. 150 for shorter runs. The best mileage I’ve clocked is 28 km per kilo, of course during a Mumbai-Pune highway run, mainly by adhering to the speed limit, and keeping the foot off the gas pedal during the downhill stretch and controlling the car by shifting down in gears. Even if you exceed the speed limit, 24km per kilo can be easily done.
    For the record, I run a 2004 Hyundai Accent 1.6 that has clocked over 200,000 kms overall, with the last 50,000 on CNG (aftermarket retrofitment, of course); and most of the wear and tear issues I’ve come to experience are more from the overall use than from CNG. The fuel, unfortunately, has taken the blame for a lot of the abuse owners pile up on their cars, be it because of a lack of knowledge, or a devil-may-care attitude. Sad, but true.

  6. @Dhruv. You make valid points. My WagonR has done over 2.5L km, half of which are on CNG. The best I have got is 26km/kg. I regularly get 20km/kg with AC in Delhi traffic. Yes, it is all about maintaining the car and the properly.

  7. I think this article suits more to people who have bought petrol car and converted to CNG. In case of factory fitted CNG, like Wagon R Green CNG, company has already done changes in body and fuel injection system design. CNG tuning is not required at all. However throttle body and injector cleaning can be applicable to factory fitted CNG car also.

  8. Friends if you are running your car on CNG ( both factory fitted or aftermarket), for optimum performance on CNG you can switch to SILVER ELECTRODE Spark Plugs from BRISK. They are specially designed to ignite hard fuels like CNG which burn at higher temperature compared to Petrol. Silver being a good conductor of electricity, these plugs enhance the pick-up, performance and improve the mileage of the car a great deal. Silver is used in Racing cars, these plugs are awesome for Petrol run cars too. Some people tend to put Iridium tip plugs in CNG cars which makes the matters worst as Iridium is hard metal, has good life but cannot give stronger current required to ignite CNG.

  9. Cars on CNG generally lower their engine life as the Valve seats and Valves get worn out due to no lubrication in the fuel and as such upper cylinder of the engine takes a beating. To stop this wear and tear, one can use JLM valve saver fluid which is a great additive and really known to work. Most conversions in Europe are not done without a valve saver as the speeds of the cars on highways is good and cars on alternate fuel would have more engine wear. With JLM valve saver, (its tested by German Institute & TUV) you stop the wear & tear owing to gas fuels or unleaded fuels (petrol), it helps in smooth performance, more mileage and cleanses the intake systems, injectors and fuel system. check out at http://www.jlmlubricants.com also on youtube search for JLM Lubricants video’s..to see how it works…a must for Petrol & CNG cars.

  10. I am using swift dezire 2009 model and i have just installed CNG conventional. Please tell me should i change the spark plug and filter and if yes, which brand should i use.

  11. If your car was serviced recently, the air filter must have been changed, and the spark plug gap adjusted. If not, do change the air filter. Dzire air filter is freely available at all spare shops for around 200 bucks. No need to change the spark plugs unless you are facing specific related problems.

  12. hi, i bought new chevy sail sedan base model petrol 3 months back….as its milage is 17,i want to fit cng to it due to high increase in petrol prices…..is it gud to fit cng ?

  13. some stray thoughts. – with a well-maintained good fitting,

    it is not necessary to run the car especially on petrol for a few kms every morning, except if there is problem on gas in cold weather.

    Spark plugs costing 150 – 200 are the fine point iridium spark plugs, and these spark plugs are not necessarily the best spark plugs for cng. NGK spark plugs costing about rs 95 are usually the best.

    cng does not beat the hell out of any engine. Engines on cng mostly remain healthier than on petrol. adding oil to petrol (as is done in 2 stroke 2 wheelers) would surely ruin the engine.

    petrol, diesel, cng or lpg do not pass through the throttle body. It is air which passes through the throttle body and it is the impurities in air which corrupt the throttle body. this corruption happens irrespective of which fuel one uses. if the air filter is cleaned/replaced regularly, throttle body would not get clogged easily. It is advisable to get throttle body cleaned once a year.

    cng tuning is required by all cars, whether factory fitted or after market fitting.

  14. Hi, i have just installed a lovato sequential kit in my logan. But m not getting the petrol like pickup as read everywhere even after tuning 2-3 times. Have installed the kit at greenglobe mumbai, an authorised centre by mahanagar gas. Please suggest me an option or where else i can get my cng tuning done. Thnx.

  15. I have maruti cng company fitted model-nov-2011 Pune. No issue when i run it on CNG. till dat 30k running is done. i would say out of that 25k running is on CNG.

    However from last 6 month i can feel car is not driving smoothly when i switch to petrol however its best when i use cng Mode. I have shown this issue to maruti service center couple of time however they said all ok.

    I can feel car runs smoothly and faster on cng mode compare to petrol Now.

    However when it was new Petrol mode speed was faster than CNG.

    does any one has faced this issue for wagon-r company fitted cng models?
    Or any one could suggest some solution i can tell to maruti servie center?

  16. Bit confused with many contras tic view on cng car maintaince. Need to know a right / reliable source for regular advise n tunig the cng fitted cars,preferably in n around NERUL, Navi Mumbai.

  17. Have had fit BRC open loop cng kit b4 6 months at khaghar. Erratic idling time / many a times car even does not idle even in engine hot condition. Low average is greatest issues. Have to run for tuning very now n then. Hence ur requested to reply with right sugesstn along with a reliable n knowledgeable mechanic for regular tuning . Thanks

  18. Hi Kalyan

    I am facing the same problem with my i10. My car on petrol does missing and the average on petrol has come down to 7-10/ltr. The company says everything is ok, but even while driving I feel CNG is better to drive than on pertol. Have you got any resolution yet?

    I have also been advised by company to add 2T engine oil in petrol, as was done in scooters. Not sure if its safe, any comments.

    Thanks
    Sandeep

  19. I have installed sequential kit in my volkswagen polo one year before.. Now it do missing when it comes to cng from petrol only first time.i have changed spark plugs as well

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