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

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.

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.

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

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.

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

Try BKR7ES

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

Are the bkr7es ones much different classicswed?

I dont know the Denso numbers without looking them up