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Thread: RPM drop problem in Cultus on CNG

  1. #1
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    Default RPM drop problem in Cultus on CNG

    Dear PWers,

    Your valuable suggestions are required for rectifying the problem in my car Cultus 2006 with 111000 kms on odo. Thermostat valve is there with auto fan. Well problem is that in the morning, car starts ok on CNG and auto choke system is turned on for about 2-3 minutes during which rpm stays at 1500 rpm. Now ideally, after some time, if race pedal is given a slight 'blip', rpm should come to around 900 rpm. But in my case, after 2-3 minutes, when I "blip" the accelerator, rpm drops down to almost zero and the engine shuts off. To prevent engine from shutting off, I had to keep a foot on race. However, this problem vanishes when the engine is fully warmed up with needle of the temperature gauge at the centre. Also, this issue is not present when I am driving on petrol.

    The situation happens between the time of auto-choke disengagement and engine warm up as well as when car is on CNG. If my engine temperature is in that range, and I have to stop a car at signal or take a turn while driving, the car engine shuts off as I have to put off a foot from race for maneuvering.

    Kindly experts shed a light on what could be the problem? Just two days ago I have done CNG Kit Service with diaphragm replaced as well as CNG cylinder service.
    @Xulfiqar @umarkhan1 @shamail_haider

    LaSallian, Ravian, NUSTian

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    Default

    get the advancer checked maybe that'll sort it out
    The Flag is the Embodiment, not of Sentiment, but of History.

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    Default

    adjust the idle speed from carb and kit both
    Just Do It Your Self!!!!!

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    Default

    This is very common problem in cultus...

    there are two issue..

    Butterfly valve need to fix.. it is cracked or cut from one side...
    Engine Head valves/caps are cracked... Car losses its pressure and engine and rpm decreases to shutdown,,

    in this issue.. car done very poor mileage...and car pick is also effected

    not major work but u can fix the car from good mechanic..

    When engine get heated the cracked become less and u feel that problem resolved but gasses between two cavities leaked .. which caused fuel waste and less pick of car..

    You notice that the issue become less in petrol..
    name : Amer
    Blood Group : SPL +ve

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    Default

    The same problem i have with my cultus, i need help in this regard please suggest me while my car rmp gets down after a 5km drive, waiting for quick reply

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    Default

    @NaXuN

    i replaced the advancer (STAP 00b) 2 weeks ago. car refused to start on both petrol and cng at that time....turned out that wires within advancer were shorted. After installing advancer, pick improves a lot on both cng and petrol.... but this rpm drop problem refuse to go out...i have not shown it to mechanic up till now hoping that the car heal itself this problem :p

    @umarkhan1

    i hope that
    this turn out be the adjustment problem when i visit mechanic ...in my opinion after disengagement of choke proper amount of fuel is not supplied to engine leading to high A/F ratio thereby decreasing power output as welll as decreasing rpm...


    @amerhassan

    butterfly was replaced about 5 months back....if butterfly problem is there, then car would also perform poorly on petrol but on petrol it is ok....moreover fuel consumption on petrol and CNG is good.....i will chk engine head for any leaks..
    LaSallian, Ravian, NUSTian

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    Default

    well the problem of rpm drop has been resolved......turned out to be just a simple CNG adjustment issue......got it adjusted from a good mechanic and now car runs fine on CNG......
    LaSallian, Ravian, NUSTian

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    Dear winsomeharis86 ,
    please Share your contact no on with me at 03338017458. i need some information from you regarding CNG tuning.
    Regards
    Ibrahim

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