2014 Hyundai Other random stalling of engine

Tiny
VIP04
  • MEMBER
  • 2014 HYUNDAI
  • 0.8L
  • 3 CYL
  • FWD
  • MANUAL
  • 3,000 MILES
I have a hyudai eon 814cc 3 cylinder mpfi. I have fitted my car with cng sequential kit. The day it was fitted the car started stalling while driving. The mechanic adjusted the ecu and advancer of cng kit and then it ran fine for some time. The car was even scanned twice at that time but didn't show any codes. Then the advance timing was set and car ran fine. But it randomly stalled someday and then the frquency of stalling increased slowly. By resetting the advncer and ecu the problem goes away for sometime but comes again. I had to drive it with very little acceleration to prevent stalling. The mechanic changed the whole cng ecu and wiring kit but the problem is still there. Sometimes the fuel change over switch doesn't work and when it works car stalls or jerks. Checked spark plugs nothing wrong. Car runs fine but random stalling occurs with increased frequency and no error code is generated. Please help as it's been four months and the mechanics can't understand the problem with it. Help will be deeply appreciated.
Tuesday, December 30th, 2014 AT 7:01 AM

13 Replies

Tiny
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  • MECHANIC
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Most of these new systems you need the correct laptop program to diagnose and adjust the gas system, are they using the correct program?
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Tuesday, December 30th, 2014 AT 12:28 PM
Tiny
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Yes sir. They use the same on all cars.
They say that only my car is giving them problems. But when the car is scanned no error shows up.
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Saturday, January 3rd, 2015 AT 6:46 AM
Tiny
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Then they need to be checking the lock off valves, gas filter, regulator and mixer. These can only be inspected by a qualified mechanic licenced to go alternative fuels.
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Saturday, January 3rd, 2015 AT 12:54 PM
Tiny
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Everything has been changed twice and checked.
When I drive it feels like there is no fuel coming in maybe the fuel injectors receive the wrong signals. Then the problem starts to come on petrol as well until the battery is disconnected. They are just going nuts over the problem, can't understand what is wrong. Maybe the petrol ecu is not in sync properly with the cng ecu.
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Saturday, January 3rd, 2015 AT 8:49 PM
Tiny
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I would consider the gas ecu, if it was adjusted and things were ok for a while I feel that the problem is there, are they sure that they know how to do the adjustments on the gas laptop computer?
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Sunday, January 4th, 2015 AT 2:44 AM
Tiny
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Sir they adjust everything and the car runs smooth for some time. And this time can be half an hour to a month. But suddenly random jerks start while driving or the engine shuts down. It feels like the spark timing
is not right. They have changed the ecu and set the advancer many times but still they can't understand the problem. Its been 4 months now and still no solution.
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Wednesday, January 14th, 2015 AT 7:12 AM
Tiny
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They need to be checking the exhaust emissions, if the engine is running lean causing the problem, I would consider replacing the gas converter, your mechanic need to be testing these things they should know what to be checking and not just trying to adjust it, if it keeps faulting there must be an issue with part of the gas conversion or their method of investigation.
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Wednesday, January 14th, 2015 AT 12:19 PM
Tiny
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If the timing is too advanced for cng, can that also cause a random misfire? I took the far over a very big bump on speed and just after that it started misfiring and after turning it off it ran smooth on petrol.
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Wednesday, January 14th, 2015 AT 9:41 PM
Tiny
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This is a DFI engine, no distributor just coil packs, there is no manual timing adjustment if that is the case.
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Thursday, January 15th, 2015 AT 1:55 AM
Tiny
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Sir I am talking about advancing the timing of spark or cng and not on petrol. Can the timing of spark cause the mixture to become lean and misfiring and engine stalling
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Thursday, January 15th, 2015 AT 7:12 AM
Tiny
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Incorrect ignition timing car cause misfire and stalling if a long way out, but the ignition timing is controled by the ECU and is the same for petrol and NCG depending on sensor inputs, I do feel that the problem is with the CNG system and not ignition or timing.
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Saturday, January 17th, 2015 AT 3:48 AM
Tiny
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The car runs fine on petrol but gives up on cng.
The check engine light flashes and there is loss of power like if the fuel injectors are not working
After that engine stops and check light goes away and the car starts running like nothing happened. After thr shutdown there is a serious problem. It fees like there is no fuel and the engine stops again and again even on petrol.
But after sometime it runs normally. The dealer syas there may be a problem with a petrol ecu but then I ask him why does the problem not coming on running in petrol and why the problem started only after fitting cng system.
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Sunday, January 18th, 2015 AT 4:43 AM
Tiny
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The problem will have NOTHING to do with the Petrol ECU or the petrol system at all.
It will be a soft ware problem with the CNG computer or a problem with the gas hardware.
You need to find a work shop that can check this over, someone that knows what they are doing, I can't do a physical diagnoses, I can just advise on what I feel is the problem with the symptoms presented.
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Sunday, January 18th, 2015 AT 12:29 PM

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