ACCENT Engine vibration/chokeup on Petrol

Peter · 25th May 2010, 14:10

Hello Team,

My Accent gls petrol has comeup with an issue all of a sudden that is quite worrying as the Car is hardly driveable on Petrol.

The car is installed with an LPG kit and hence can be run on Multifuel.

The Issue:

The issue is that when the Car is started or driven on Petrol there is feeling as if the engine gets kind of choked up at the very start and then suddenly accelerates as if the Petrol flow has just been increased..also if the car is driven at high speed then it continues to move smoothly... but when the speed is reduced then the choked feel comes in again and in case of hard braking then the car just shutsoff.

Another thing that Ive noticed is that when the car is idling the engine vibrates intermittenlty as if someone is witholding the fuel flow or something to the engine

and the RPM is at 500/600 and never goes beyond this whereas the normal rpm reading previously would always be at 1000.

And for the most interesting fact...The Car runs/idles smooth on LPG.. no issues on LPG whatsoever and the RPM is at normal reading as well which is 1000, performance is normal on LPG as well, somehow its only on Petrol that the issue is occuring.

Things done so far to resolve with no success:

Replaced spark plugs / no success
Cleaned the Injectors / no success
Replaced the fule pump and filter / no success

The local mechanics are now at a loss to figure out as to whats the issue on Petrol as on LPG everything is just fine.

Can you please share your inputs/ suggestions on this issue ?

Any similar occurences of such type with anyone?

Please advice,

Regards,
Peter.

SirAlec · 25th May 2010, 15:03

since you have changed and cleaned most of the suspected parts.
Here is a simple task you should do. Clean the tank and fuel lines.

Peter · 25th May 2010, 16:15

Quote:

Originally Posted by SirAlec

since you have changed and cleaned most of the suspected parts.
Here is a simple task you should do. Clean the tank and fuel lines.

Thanks for the reply SirAlec..

The tank was very clean when inspected , since the fuel pump was removed the tank contents were very much visible and hence can confirm on its status... the fuel line has not yet been looked at though.

Am just wondering whether this could be the likely problem? is it normally easy to clean the fuel line or replace ?

Any ideas team ??

SirAlec · 25th May 2010, 21:07

Its a easy job. You just need a high pressure air compressor.

harsha.cs1 · 26th May 2010, 11:50

To add to it, is yours a closed loop kit with a lamda controller? if so, do check the tuning on the lamda controller - the tuning on it also controls petrol performance including idling on petrol etc.
the lamda controller is connected to a laptop and many of the parameters are then set separately for petrol and for lpg.

mohit333 · 27th May 2010, 11:05

I faced a similiar problem but it was resolved by replacing the relay for the fuel pump. Just check if that's the issue with your car.

Peter · 27th May 2010, 13:56

Team,

Mine is an Open Loop Kit of LPG..

The fuel line has been cleaned... no success

The technician has informed that the relay is no problem...

Any ideas/suggestions on this issue ?

SirAlec · 27th May 2010, 16:21

Then i suspect the LPG kit mainly petrol solenoid valve and emulator. Emulator remains on even in Petrol mode.

harsha.cs1 · 29th May 2010, 11:52

Quote:

Originally Posted by SirAlec

Then i suspect the LPG kit mainly petrol solenoid valve and emulator. Emulator remains on even in Petrol mode.

Yes possibly. In fact, I have been facing the opposite trouble.
My car sometimes idles very low and turns off on LPG. When revved high, it does ok. and it runs great on petrol. Typically, I see that this happens due to the LPG filter getting choked with dust. But i sometimes wonder if there could be any other reason as well - coz the filters ideally need to be cleaned only once in like 7.5k kms. But i end up doing it a lot more often like in 2.5K kms.

Peter · 1st June 2010, 18:47

Team,

The issue is now resolved

Somehow one of the wires going from the engine to the ECM via a relay ( LPG kit ) was cut, the wire was rejoined and the ECM reset via a battery disconnect and the Car is purring as normal now.

Thanks for all your help.

Cheers

Peter.

gigy · 1st June 2010, 19:00

do you have more detail on this wire, where was it joined to the ecm circuit?

SirAlec · 5th June 2010, 22:38

Quote:

Originally Posted by Peter

Team,

The issue is now resolved

Somehow one of the wires going from the engine to the ECM via a relay ( LPG kit ) was cut, the wire was rejoined and the ECM reset via a battery disconnect and the Car is purring as normal now.

Thanks for all your help.

Cheers

Peter.

Its definitely the cable from emulator to ECU, that fools ECU when running in LPG mode of different sensors signals.

25th May 2010, 14:10	#1
Peter BHPian Join Date: Sep 2007 Location: Mumbai Goa Posts: 205 Thanked: 49 Times View My Garage	ACCENT Engine vibration/chokeup on Petrol Hello Team, My Accent gls petrol has comeup with an issue all of a sudden that is quite worrying as the Car is hardly driveable on Petrol. The car is installed with an LPG kit and hence can be run on Multifuel. The Issue: The issue is that when the Car is started or driven on Petrol there is feeling as if the engine gets kind of choked up at the very start and then suddenly accelerates as if the Petrol flow has just been increased..also if the car is driven at high speed then it continues to move smoothly... but when the speed is reduced then the choked feel comes in again and in case of hard braking then the car just shutsoff. Another thing that Ive noticed is that when the car is idling the engine vibrates intermittenlty as if someone is witholding the fuel flow or something to the engine and the RPM is at 500/600 and never goes beyond this whereas the normal rpm reading previously would always be at 1000. And for the most interesting fact...The Car runs/idles smooth on LPG.. no issues on LPG whatsoever and the RPM is at normal reading as well which is 1000, performance is normal on LPG as well, somehow its only on Petrol that the issue is occuring. Things done so far to resolve with no success: Replaced spark plugs / no success Cleaned the Injectors / no success Replaced the fule pump and filter / no success The local mechanics are now at a loss to figure out as to whats the issue on Petrol as on LPG everything is just fine. Can you please share your inputs/ suggestions on this issue ? Any similar occurences of such type with anyone? Please advice, Regards, Peter.
	() Thanks

25th May 2010, 15:03	#2
SirAlec Senior - BHPian Join Date: Sep 2006 Location: zxc Posts: 3,393 Thanked: 726 Times	since you have changed and cleaned most of the suspected parts. Here is a simple task you should do. Clean the tank and fuel lines.
	() Thanks

25th May 2010, 21:07	#4
SirAlec Senior - BHPian Join Date: Sep 2006 Location: zxc Posts: 3,393 Thanked: 726 Times	Its a easy job. You just need a high pressure air compressor.
	() Thanks

26th May 2010, 11:50	#5
harsha.cs1 BHPian Join Date: Feb 2008 Location: Bangalore Posts: 224 Thanked: 2 Times	To add to it, is yours a closed loop kit with a lamda controller? if so, do check the tuning on the lamda controller - the tuning on it also controls petrol performance including idling on petrol etc. the lamda controller is connected to a laptop and many of the parameters are then set separately for petrol and for lpg.
	() Thanks

27th May 2010, 11:05	#6
mohit333 BHPian Join Date: Mar 2007 Location: Mumbai Posts: 46 Thanked: 3 Times	I faced a similiar problem but it was resolved by replacing the relay for the fuel pump. Just check if that's the issue with your car.
	() Thanks

27th May 2010, 13:56	#7
Peter BHPian Join Date: Sep 2007 Location: Mumbai Goa Posts: 205 Thanked: 49 Times View My Garage	Team, Mine is an Open Loop Kit of LPG.. The fuel line has been cleaned... no success The technician has informed that the relay is no problem... Any ideas/suggestions on this issue ?
	() Thanks

27th May 2010, 16:21	#8
SirAlec Senior - BHPian Join Date: Sep 2006 Location: zxc Posts: 3,393 Thanked: 726 Times	Then i suspect the LPG kit mainly petrol solenoid valve and emulator. Emulator remains on even in Petrol mode.
	() Thanks

1st June 2010, 18:47	#10
Peter BHPian Join Date: Sep 2007 Location: Mumbai Goa Posts: 205 Thanked: 49 Times View My Garage	Team, The issue is now resolved Somehow one of the wires going from the engine to the ECM via a relay ( LPG kit ) was cut, the wire was rejoined and the ECM reset via a battery disconnect and the Car is purring as normal now. Thanks for all your help. Cheers Peter.
	() Thanks

1st June 2010, 19:00	#11
gigy Senior - BHPian Join Date: Jul 2006 Location: mumbai Posts: 1,321 Thanked: 47 Times	do you have more detail on this wire, where was it joined to the ecm circuit?
	() Thanks