[HimuraKenshin]

Originally Posted by CARDEEP

I guess your CNG settings need to be tweaked (they call it tuning), your CNG flow is higher than required due to which you aren't experiencing much power loss, which is perceptible generally.

You will observe major loss, say- 15-20%, in the power (basically low end torque), but your mileage will improve, & it would require extracting best from engine before every gear shift. Probably, you won't love your car after this, but, the cost savings will hold you back IMO.

I believe this should help.

hi my CNG mechanic told me that my cng flow is fine. Its all controlled by the lambda and the other electronics as this is a closed loop system.
i got my air filter aswell as my spark plugs changed to NGK ones...

i hoped that after this, my FE would increase, but to my dismay, it hasnt, not even a bit. it is still giving on 13.6/KG

My CEL light stays on, this started after fitting the CNG kit...
The cng mech told me that it is normal.

I dont know what i should do now....
please help me out...
Should i change the O2 sensor?

[ptaneja]

Both mileage and check-engine light are world apart - 99% of mechanics and service advisers I met gave me the same comment "this is normal in CNG vehicles" . Can you have the mechanic replace "Advancer", clear the ECU memory and see if it helps ? because replacing advancer was the only thing that got rid of the error for me. (on the other hand I don't have Lambda in my kit )

For mileage, I am really amazed - for my heavier vehicle (SX4), I am travelling approx 160kms for 320rs worth of gas. Rule of thumb now-a-days is that you should be getting approx 2rs/km of running on CNG. Whats the mileage you are getting on petrol ?

[HimuraKenshin]

Originally Posted by ptaneja

Both mileage and check-engine light are world apart - 99% of mechanics and service advisers I met gave me the same comment "this is normal in CNG vehicles" . Can you have the mechanic replace "Advancer", clear the ECU memory and see if it helps ? because replacing advancer was the only thing that got rid of the error for me. (on the other hand I don't have Lambda in my kit )

For mileage, I am really amazed - for my heavier vehicle (SX4), I am travelling approx 160kms for 320rs worth of gas. Rule of thumb now-a-days is that you should be getting approx 2rs/km of running on CNG. Whats the mileage you are getting on petrol ?

I shall speak to him about the advancer...
i dont really remember the last time i calculated FE on petrol. as far as i remember, its was around 13~14...
do you suggest anything?

[pranav4x4]

So finally I got my 2005 Honda City iDSi converted to CNG from eco fuel center Thane (Lovato closed loop system). Been a week now, here's some initial observations:
1. NO check engine light - a big relief.

2. The car has lost 15% power on CNG, and the sound has changed to a lower pitched, less exciting note (somewhere between petrol and diesel when revved) That said, for normal driving the difference is imperceptible both sound and power loss. The car runs exceptionally smoothly when driven forgivingly. Overall better than expected, so quite happy.
The feel when on Petrol is unchanged

3. In the city, the City is getting 21kpkg, and on highway (pune trip) it got 33 kpkg. I keep telling people that I am getting "40 kpl city and 64 kpl highway in petrol cost equivalents" which puts it at par with a Honda Activa. (Of course, this is only fuel cost, that too without the bit of petrol consumed, not total running cost.

4. On the 4th day, while converting to CNG the car stalled, and refused to start again - quite a scare, but on diagnosis the battery, which was end-of-life anyway, had given up. It was replaced and things are fine now. I don't think CNG would have had much to do with it.

5. One major niggle remains however - the switching between Petrol and CNG is not smooth. Without revving, for CNG -> Petrol, the car goes to a very low rpm, almost stalls and then picks up again. For Petrol -> CNG, it almost always stalls. It looks like the delay between petrol stopping, and then the CNG flow starting, is too high. I would appreciate any tips on how this can be resolved. The dealer dint have much clue. In both switches, if i rev the car hard, it does not stall, but I am not keen to rev it hard for every switch.

6. As a best-practice, some people recommend running it on Petrol for first and last km of drive - I understand the first km, but is the last km also required? In my case since the switching is not smooth, it becomes a big chore.
Also, as maintenance best practice - people suggest throttle body cleaning and air filter change more frequently than before - anything else to be done?

[ptaneja]

Originally Posted by pranav4x4

So finally I got my 2005 Honda City iDSi converted to CNG from eco fuel center Thane (Lovato closed loop system). Been a week now, here's some initial observations:
1. NO check engine light - a big relief.

2. The car has lost 15% power on CNG, and the sound has changed to a lower pitched, less exciting note (somewhere between petrol and diesel when revved) That said, for normal driving the difference is imperceptible both sound and power loss. The car runs exceptionally smoothly when driven forgivingly. Overall better than expected, so quite happy.
The feel when on Petrol is unchanged

3. In the city, the City is getting 21kpkg, and on highway (pune trip) it got 33 kpkg. I keep telling people that I am getting "40 kpl city and 64 kpl highway in petrol cost equivalents" which puts it at par with a Honda Activa. (Of course, this is only fuel cost, that too without the bit of petrol consumed, not total running cost.

4. On the 4th day, while converting to CNG the car stalled, and refused to start again - quite a scare, but on diagnosis the battery, which was end-of-life anyway, had given up. It was replaced and things are fine now. I don't think CNG would have had much to do with it.

5. One major niggle remains however - the switching between Petrol and CNG is not smooth. Without revving, for CNG -> Petrol, the car goes to a very low rpm, almost stalls and then picks up again. For Petrol -> CNG, it almost always stalls. It looks like the delay between petrol stopping, and then the CNG flow starting, is too high. I would appreciate any tips on how this can be resolved. The dealer dint have much clue. In both switches, if i rev the car hard, it does not stall, but I am not keen to rev it hard for every switch.

6. As a best-practice, some people recommend running it on Petrol for first and last km of drive - I understand the first km, but is the last km also required? In my case since the switching is not smooth, it becomes a big chore.
Also, as maintenance best practice - people suggest throttle body cleaning and air filter change more frequently than before - anything else to be done?

A drop in RPM when it's switching over is normal - dont worry about it.

And don't go by the so called best practice of running the car on petrol - not required at all, just make sure that you start the car on Petrol, and that's more than enough.
Throttle Body + Air Filter are the major reason car "misses". Next would be injector cleaning and tapet adjustment when you see RPM fluctuating in an idle car. Other than that normal servicing - though would recommend doing it at 8K kms rather than normal 10K.

[rajeshchand]

Originally Posted by pranav4x4

2. The car has lost 15% power on CNG, and the sound has changed to a lower pitched, less exciting note (somewhere between petrol and diesel when revved) That said, for normal driving the difference is imperceptible both sound and power loss. The car runs exceptionally smoothly when driven forgivingly. Overall better than expected, so quite happy.
The feel when on Petrol is unchanged

6. As a best-practice, some people recommend running it on Petrol for first and last km of drive - I understand the first km, but is the last km also required? In my case since the switching is not smooth, it becomes a big chore.
Also, as maintenance best practice - people suggest throttle body cleaning and air filter change more frequently than before - anything else to be done?

To throw some light on these alternate fuel systems, i have driven on LPG since 2000 and on CNG / LPG on low end and high end vehicles since 2003 till 2009. My observations:

The power loss of 15% is what you experience now, it keeps increasing over period of time and reaches a stage over 20-50000 kms (it varies from vehicle to vehicle and brand to brand) that you will literally stop driving the vehicle. Here you have to think about the cost effectiveness or driving pleasure, of course if you have an alternate vehicle for spirited driving then for daily grind you can have this kind of vehicle. I have driven Santro, Esteem and Elantra all on LPG / CNG, the experience have been the same, except that Santro did 60k km before engine head change, Esteem did 80k km before engine overhaul and Elantra did 100k km before engine head change (it is still in workshop). Yes, some people might argue that the cost you might save over the years by driving on LPG / CNG is much more than even a engine overhaul cost, so that makes sense.

Not to mention, the resale value of the vehicle takes a big hit and it goes literally for nothing.

Of course, if this is a second vehicle then definitely this alternate fuel source is a great money saver, no doubts on it, just wanted to give my 2 cents on this, not to discourage any guys out here, just my experience of 8 years on these fuels.

[pranav4x4]

Originally Posted by ptaneja

A drop in RPM when it's switching over is normal - dont worry about it.

But in my case the switch-over is so jerky, that I am afraid that might damage the engine (and the catalytic converter, from running on a too-lean mixture) more than the alleged damage from CNG itself.

As I mentioned, the car always stalls completely in the petrol->CNG switch.
Some people mentioned in this forum that they have a smooth switchover, almost imperceptible - so I am keen to see if there is some way to improve it.

[carboy]

Originally Posted by pranav4x4

As I mentioned, the car always stalls completely in the petrol->CNG switch.

This happens to me only if I change as soon as starting the car. If it's done automatically (i.e as soon as the RPM increases) or manually after a few minutes of driving, the switchover never stalls.

Originally Posted by rajeshchand

I have driven Santro, Esteem and Elantra all on LPG / CNG, the experience have been the same, except that Santro did 60k km before engine head change, Esteem did 80k km before engine overhaul and Elantra did 100k km before engine head change (it is still in workshop). Yes, some people might argue that the cost you might save over the years by driving on LPG / CNG is much more than even a engine overhaul cost, so that makes sense.

How much did the engine overhaul cost you?

[frankmehta]

Hello, people. Any idea about who in Mumbai can do good, professional Sequential kit installations in cars?? I know someone who does a good job with open and closed loop kits but every time you mention sequential kits to him, he says the average will be very poor with sequential kits. Does anyone here know a fitter with the expertise to fit, say a V6 engine with a Sequential CNG kit?? I need to know real soon.

[rajeshchand]

Originally Posted by carboy

How much did the engine overhaul cost you?

Engine work on each of the vehicle costed me right from 40k to 90k, yes here you can do the maths on cost effectiveness

[pranav4x4]

Originally Posted by frankmehta

Hello, people. Any idea about who in Mumbai can do good, professional Sequential kit installations in cars?? I know someone who does a good job with open and closed loop kits but every time you mention sequential kits to him, he says the average will be very poor with sequential kits. Does anyone here know a fitter with the expertise to fit, say a V6 engine with a Sequential CNG kit?? I need to know real soon.

I can tell you none of the dealers in the Thane/Mulund area seem to have the confidence/expertise on sequential. Check with Dashmesh Impex Vashi (Not from my personal experience, but he's received some praise elsewhere on this forum)

[paras211]

Originally Posted by frankmehta

Hello, people. Any idea about who in Mumbai can do good, professional Sequential kit installations in cars?? I know someone who does a good job with open and closed loop kits but every time you mention sequential kits to him, he says the average will be very poor with sequential kits. Does anyone here know a fitter with the expertise to fit, say a V6 engine with a Sequential CNG kit?? I need to know real soon.

green globe in mulund is popular, see a lot of radio cabs there, and a friend knows the chap too , and we can meet up when you come to mulund.

[Ragin_Ice]

Hey Pranav4x4 congrats on the installation and brilliant mileage. I have a City 2007 ZXi. Wanted to ask you a few questions on the phone BUT I can't send PMs (I guess because of the post count. It anyone knows the reason please let me know) I would really appreciate if you can PM me your number. Thanks in advance.

[ptaneja]

Today I witnessed something unique and strange for the first time !

On getting my car refilled at CNG pump, a black Accent was also getting filled up. When I saw the meter reading, it said, 650rs...and it stopped at approx 730 or so. I was like "***"! 19kgs of CNG ?!
On asking the owner, as to what the story is, he said that he has 2 cylinders installed!

I have never heard or rather seen anything like this.

Wish I had time to check his setup

[carboy]

Originally Posted by ptaneja

On getting my car refilled at CNG pump, a black Accent was also getting filled up. When I saw the meter reading, it said, 650rs...and it stopped at approx 730 or so. I was like "***"! 19kgs of CNG ?!
On asking the owner, as to what the story is, he said that he has 2 cylinders installed!

Each cylinder is like an extra adult in weight. Before I installed CNG in my swift, 5 people in car was no problem. After the CNG installation, if there are 5 people in the car, the underside scrapes some speed breakers because it's actually like 6 people now. I avoid more than 4 (3 + 1) in the car now.

Related question - why are the cylinders so heavy - is it because of cost - I think you can have lighter cylinders made from more expensive material. I would be ready to pay 5000 extra for having lighter cylinders with the same capacity.