Cause
Restricted alternative fuel filter
The filter in a gaseous fuel system has become restricted.
This is the most under-serviced part on a converted vehicle, and the reason is administrative rather than technical. A gas conversion is usually aftermarket, so it does not appear in the vehicle's service schedule; the car changes hands, and nobody who owns it afterwards knows the filter exists. A conversion with several previous owners has very often never had one changed.
LPG carries oily residue and heavy ends that the filter is there to catch, so restriction is a matter of time rather than of anything going wrong. It builds gradually, which is why the symptoms arrive as a slow decline nobody can date: worse economy, hesitation under load, longer changeover times, and eventually the system giving up and staying on petrol.
The diagnostic signature is a pressure difference. Healthy tank pressure with low pressure at the regulator inlet means a restriction between them, and the filter is the first thing in that path worth suspecting.
It is cheap, and it is worth asking about before anything expensive is quoted. A vaporizer, a regulator or a pressure sensor can all be blamed for what a filter is doing.
Typically a moderate job.
Codes this can cause (18)
Codes where this is a likely explanation first, rather than merely a possible one.
- P2A3E Alternative Fuel Delivery Error Likely for this code High
- P2A6E Alternative Fuel Rail Pressure Regulator Inlet Pressure Too Low Likely for this code High
- P2A6F Alternative Fuel Rail Pressure Regulator Inlet Pressure Too High Likely for this code High
- P2BB0 Alternative Fuel Consumption Too Low Likely for this code Moderate
- P2A3F Excessive Time to Enter Alternative Fuel Control Moderate
- P2A40 Alternative Fuel System - Injector Leakage to Rail Detected High
- P2A69 Alternative Fuel Rail Pressure Regulator Inlet Pressure Sensor Circuit High
- P2A6A Alternative Fuel Rail Pressure Regulator Inlet Pressure Sensor Range/Performance High
- P2A6B Alternative Fuel Rail Pressure Regulator Inlet Pressure Sensor Circuit Low High
- P2A6C Alternative Fuel Rail Pressure Regulator Inlet Pressure Sensor Circuit High High
- P2A6D Alternative Fuel Rail Pressure Regulator Inlet Pressure Sensor Circuit Intermittent/Erratic High
- P2A8B Alternative Fuel Vaporizer A Performance High
- P2A8C Alternative Fuel Vaporizer B Performance High
- P2A8D Alternative Fuel Vaporizer C Performance High
- P2A8E Alternative Fuel Pump A Performance High
- P2A8F Alternative Fuel Pump B Performance High
- P2A90 Alternative Fuel Pump C Performance High
- P2AA2 Alternative Fuel Return Line Insufficient Flow High
Information, not instruction
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