LPG idle misfire issues

Jason t5 · Jul 24th, 2023, 19:05

Hi all I'm looking for some advice on my v70 T5 2003. I've had the car 6mths now and the gas has been a nightmare (it was fine when I bought it) I had new injectors fitted as one went down.. all was well for a while but then the car develops a rough idle and misfire on LPG when cold. When my LPG installer remaps the gas all is well for a couple of hundred miles and the problem keeps coming back.. it starts off with a splutter on changeover and progressively gets worse to the point where it's running rough on LPG until I've done about 30 mins of driving and then it seems to sort itself out! The odd thing is if I keep the revs over 2000rpm it's fine and if I switch to gas say on the m/way it acts normal? Every thing is running fine if I leave it on petrol! I've also had the ECU changed on the LPG system but it's still acting up.. any advice on what else to look for please this really has left me and my LPG tech scratching our heads. Many thanks

classicswede · Jul 25th, 2023, 23:14

Some details on the system might help

At the moment there are lots of heavy ends in some LPG supplies as it is reused LPG that has been used as a chemical scrubber. It is ok for heating etc but not good for running engines. The vapouriser and injectors might need a clean out

Air leaks, has a smoke test been done? Any air leaks will cause a lot more issues on LPG than they will on petrol

Spark plugs, what plugs are you running? You want to be on NGK or Denso single prong plugs.

Jason t5 · Jul 26th, 2023, 17:29

Hi thanks for the reply. As far as the LPG system goes it's got a full new set of barracuda injectors installed and a king ECU, the rest of the system I'm not too sure on. It's had a new set of NGK plugs in recently. Its also had a new set of vacuum lines installed a couple of months ago as mine were perished which was diagnosed with a smoke test so that should be all fine.

classicswede · Jul 27th, 2023, 21:17

Can you check what part number you have on the spark plugs?

Jason t5 · Oct 3rd, 2023, 13:06

I'm running the NGK bkr6eix plugs. Sorry for the late reply we thought we had solved the problem with a clean out of the injectors (they was filthy) but the problem has not got away.

CNGBiFuel · Oct 28th, 2023, 16:06

There may well be more going on, only by my reckoning you've £60-80 in spark-plugs alone. Why these? Mine are £10 for the set. And £60-80 might actually be worse. 0.7mm

classicswede · Nov 15th, 2023, 10:09

Try BKR7ES

Jason t5 · Nov 29th, 2023, 13:57

I have tried the Denso K20PR-U 3145 plugs and gapped them to 0.6 but it's still having none of it

Jason t5 · Nov 29th, 2023, 13:59

Are the bkr7es ones much different classicswed?

classicswede · Nov 29th, 2023, 14:45

I dont know the Denso numbers without looking them up

Jul 24th, 2023, 19:05	#1
Jason t5 New Member Last Online: Apr 22nd, 2024 19:42 Join Date: Feb 2023 Location: White British	LPG idle misfire issues Hi all I'm looking for some advice on my v70 T5 2003. I've had the car 6mths now and the gas has been a nightmare (it was fine when I bought it) I had new injectors fitted as one went down.. all was well for a while but then the car develops a rough idle and misfire on LPG when cold. When my LPG installer remaps the gas all is well for a couple of hundred miles and the problem keeps coming back.. it starts off with a splutter on changeover and progressively gets worse to the point where it's running rough on LPG until I've done about 30 mins of driving and then it seems to sort itself out! The odd thing is if I keep the revs over 2000rpm it's fine and if I switch to gas say on the m/way it acts normal? Every thing is running fine if I leave it on petrol! I've also had the ECU changed on the LPG system but it's still acting up.. any advice on what else to look for please this really has left me and my LPG tech scratching our heads. Many thanks

Jul 25th, 2023, 23:14	#2
classicswede Trader Volvo in my veins Last Online: Yesterday 23:53 Join Date: Dec 2004 Location: Anglesey	Some details on the system might help At the moment there are lots of heavy ends in some LPG supplies as it is reused LPG that has been used as a chemical scrubber. It is ok for heating etc but not good for running engines. The vapouriser and injectors might need a clean out Air leaks, has a smoke test been done? Any air leaks will cause a lot more issues on LPG than they will on petrol Spark plugs, what plugs are you running? You want to be on NGK or Denso single prong plugs. __________________ http://www.classicswede.org www.classicswede.co.uk

Jul 27th, 2023, 21:17	#4
classicswede Trader Volvo in my veins Last Online: Yesterday 23:53 Join Date: Dec 2004 Location: Anglesey	Can you check what part number you have on the spark plugs? __________________ http://www.classicswede.org www.classicswede.co.uk

Oct 28th, 2023, 16:06	#6
CNGBiFuel Classic P80 1999 BiFuel Last Online: Mar 6th, 2024 00:34 Join Date: Aug 2012 Location: 48mph Middle Lane M4	There may well be more going on, only by my reckoning you've £60-80 in spark-plugs alone. Why these? Mine are £10 for the set. And £60-80 might actually be worse. 0.7mm __________________ Bifuel V70 Classic 1999 [The Old Grumpy in the Corner, "When I was a lad... blah, bl**dy blah."]

Nov 15th, 2023, 10:09	#7
classicswede Trader Volvo in my veins Last Online: Yesterday 23:53 Join Date: Dec 2004 Location: Anglesey	Try BKR7ES __________________ http://www.classicswede.org www.classicswede.co.uk

Jul 26th, 2023, 17:29	#3
Jason t5 New Member Last Online: Apr 22nd, 2024 19:42 Join Date: Feb 2023 Location: White British	Hi thanks for the reply. As far as the LPG system goes it's got a full new set of barracuda injectors installed and a king ECU, the rest of the system I'm not too sure on. It's had a new set of NGK plugs in recently. Its also had a new set of vacuum lines installed a couple of months ago as mine were perished which was diagnosed with a smoke test so that should be all fine.

Oct 3rd, 2023, 13:06	#5
Jason t5 New Member Last Online: Apr 22nd, 2024 19:42 Join Date: Feb 2023 Location: White British	I'm running the NGK bkr6eix plugs. Sorry for the late reply we thought we had solved the problem with a clean out of the injectors (they was filthy) but the problem has not got away.

Nov 29th, 2023, 13:57	#8
Jason t5 New Member Last Online: Apr 22nd, 2024 19:42 Join Date: Feb 2023 Location: White British	I have tried the Denso K20PR-U 3145 plugs and gapped them to 0.6 but it's still having none of it

Nov 29th, 2023, 13:59	#9
Jason t5 New Member Last Online: Apr 22nd, 2024 19:42 Join Date: Feb 2023 Location: White British	Are the bkr7es ones much different classicswed?

Nov 29th, 2023, 14:45	#10
classicswede Trader Volvo in my veins Last Online: Yesterday 23:53 Join Date: Dec 2004 Location: Anglesey	I dont know the Denso numbers without looking them up __________________ http://www.classicswede.org www.classicswede.co.uk

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