LPGC wrote:
Still far too many iffs and buts to advise properly..
Less pronounced on petrol implies the situation still occurs on petrol, which could point to a general vehicle problem (none LPG related) or could point to a fuel trim issue caused by LPG calibration. A general vehicle problem will often be exagerated when running on LPG because the mixture must be correct to more extend than when running on petrol and LPG ignition temp is higher. Proximity of LPG injectors to air filter housing could mean that when the airfilter was fitted differently it pushed against LPG injectors and could cause pipes between LPG injectors and manifold to kink. If your LPG system was calibrated (in a certain way) while the MAF sensor wasn't working properly, and then you corrected the MAF sensor problem, it might run worse on LPG after you sorted the MAF sensor issue. A lot of vehicle problems could point to crank sensor and MAF sensor issues, but again wouldn't it be a coincidence for a sensor to go wrong while you were having the LPG system fitted... There'd be nothing baffling to an engine running poorly going downhill (on over-run) on LPG, would be an indicator to me that calibration was off at very low loads and/or LPG injectors were being tasked with working below minimum pulse duration for which they can accurately meter fuel, and/or LPG ECU invoked a minimum LPG injector pulse duration (which would mean over-run would be rich).
With those sorts of iffs and buts you might as well bring it in to me, or ask your installer to re-consider the likelihood of coincidence of such faults occurring on petrol too at around the time you had the LPG system fitted. Such coincidences do occur, I converted a BMW in January and the crank sensor went on it a fortnight later, before I'd seen the car following the fault I too thought I must have caused the problem so met the owner half way between me and London. Your installer needs to be less quick to rule out his work as the cause of the problem, he should at least have a look instead of fobbing you off.
Simon
Hi Simon
Yes its all guess work at the moment, like I mentioned before this is a working vehicle but I need to find time to travel down to you to let you have a look at it, you can service the Gas side at the same time if you wish, its overdue, been putting it off until I could locate the cause of the rough running and stalling problems, the cutting out is the most worrying part, it tends to just cut out at junctions usually after driving down hill, but not every time? you will have to let me know when you are available to have a look at the vehicle?
Dale