[Herschey]

Originally Posted by BikerKeeda

I've been searching about VALVE STRINGS and I couldn't find any information.

There is nothing called valve strings since valves have always been in a no strings attached situation.

Jokes apart, your local mechanic most likely meant valve springs which is the spring that keeps the valves rightly in their place and in closed position. It may go kaput primarily in three ways - 1) By losing its tension and thereby unable to bring the valves to a perfect close. 2) Unable to bring the valves to a close in due time, also known as floating, and 3) By loosing its shape thereby not seating the valves perfectly. In all cases, the vehicle would have leaking valves and thereby a leaky head which can be easily traced by various methods. The best part is that the situation is easily repairable but if left unattended, it may cause the head gasket to leak and cause major damage.

While its a little tricky to clearly point out to valve springs as the main culprit, a probable giveaway of this situation is a loss in engine compression which would lead to engine misfire, overheating, a clearly identifiable drop in pickup, and the development of engine back pressure where the engine might also throw out black smoke. This typically happens at higher engine RPMs and the engine might still run normally at idle or low RPMs.

Since your car has already covered decent mileage, you can take it to a reputed mechanic and get all springs replaced, even if one or two of them seem absolutely fine. Once this is done, you would still need to get the CNG system properly tuned.

[BikerKeeda]

Originally Posted by Herschey

There is nothing called valve strings since valves have always been in a no strings attached situation.

Good one

Even I suspected the same, so after struggling for 4 hours and failing, I messaged the installer to confirm whether he meant Strings/ Springs. But he replied saying Strings

So finally I surrendered myself to Bhpians here

[Shreyans_Jain]

Originally Posted by BikerKeeda

there is not problem in Petrol


I visited the center this morning, the mechanic and owner checked the car and told me there is no problem with tuning or the kit and I need to replace the VALVE STRINGS from service center. It will cost me around 10k INR according to his estimate. He quoted VALVE STRINGS typically need a replacement @1Lac +-20k kms.

The fact that your engine runs fine on petrol means that there is nothing fundamentally wrong with it.

There is nothing called valve strings. It is valve springs. And this is not a part that fails in Maruti cars, unless it’s a rarest of rare case. Had the springs been bad, your car wouldn’t be running fine on petrol. But then, you say it does. So, my take is that the person who pointed you in this direction is also trying to take you for a ride.

Focus your energies on finding a reputed installer who can reconfigure your CNG kit. All you need to ensure on the engine side of things is that your air filter is new and throttle body is clean. Don’t worry about spark plugs and ignition coils. If and when they go bad, your car will start misfiring on gas with a loud ‘phattt’ sound. It is unmissable.

[X-Saint]

Originally Posted by BikerKeeda

installed Tomasetto kit, and there is not a problem in Petrol

I hope your issue is resolved by now. If not then below are a few suggestions.

Have you scanned the ECU with an OBDII scanner? If not please do that first, any FNG would do it. If there are no faults in ODBII scanning then get the throttle body cleaned thoroughly by taking the assembly out and not just by spraying the throttle body cleaner. Also, check the throttle valve.

I had faced a similar issue in my 2015 Santro Xing with Lovato kit.

[dRC18]

I am also facing a similar situation in my celerio vxi amt. I had installed Lovato cng kit form a reputed authorised Lovato dealer in my town. I had installed the cng kit at 70k. Post installation the car ran fine for almost 50k after which i started seeing the problem like random fluctuations in rpm. I also saw engine check light randomly come and go. Upon inspection with obd tool it showed engine misfire in all the cylinders. I also did the same troubleshooting as everyone suggested, cleaned the trottle body, replaced the spark plugs and coils, fine tuning of the software, but the end result was same. The problem never got solved. After visiting several mechanics everyone suggested the same thing, replace the engine valves. My car still runs fine on petrol and it never shuts down as its an amt, but its not the case with cng. I am yet to come to any full proof solution.

[pg2003]

Mine is factory fitted by Hyundai, have driven close to 1.4Lacs and never had to get the cng tuned till date. But all good things come to an end.

On Sunday car went through OBD2 Scan, detected misfiring in cylinder 2&4, in addition to the fault of driver side airbag for which I had got the same done, clock spring being the culprit, ordered through Hyundai genuine part dealer.

Got the spark plugs gap checked and throttle body thoroughly cleaned, however, earlier there was no missing noticeable on low rpms, but now I'm getting the issue of power loss at initial revvs, and also with AC on

Scanner person says the most probably the advancer has gone Kaput and to put the engine in direct cng mode and check however, have visited to a couple of cng retrofitters, as per them the advancer plug is 24 pin, and they have 16 or 18 pin couplers only, and the advancer will be available only through Hyundai, and I'm not a fan of Hyundai service centres at all. They take a lot of time to get even a small thing done.

I was planning to use this car for around another year or so, but that's becoming more and more difficult day by day, and Altroz cng becoming more and more enticing.