We have been working with LPG systems since we opened the shop. In that time we have seen everything that can go wrong with autogas. Some problems come up over and over. Here is a rundown of the most common faults, with real examples from the shop floor.
Worn LPG Injectors
The number one problem by frequency. LPG injectors go through millions of open-close cycles. Over time, seals wear out, springs weaken, and dosing becomes imprecise.
How it shows up: Jerking while driving, rough running, increased consumption. Usually one or two injectors go bad, so the engine runs unevenly.
From the shop: A Punto 1.2 at 130,000 km. Owner complained about jerking. One injector was flowing 40 percent more than the others. Ultrasonic cleaning fixed it in an hour.
Injectors are typically serviced at 80,000 to 100,000 km, with full replacement at 150,000 to 200,000 km.
Reducer Membrane
The reducer converts liquid LPG into gas. Inside it there is a membrane that regulates flow and pressure. Over time it loses elasticity, cracks, or deforms.
How it shows up: Hard starting on gas, unstable idle, reverting to petrol, loss of power. Worse in winter because a cold reducer struggles.
From the shop: A Golf 5 1.6. Owner says "the gas only works when the engine is hot." Membrane was cracked. Replaced the membrane and gaskets, and the reducer was good as new.
Clogged Filters
A simple problem that does serious damage if ignored. LPG at our stations is not always clean. The filter catches contaminants, but once it is saturated, flow drops and the system suffers.
How it shows up: Gradual loss of performance on gas, weakness under load, higher consumption. Because it is gradual, many drivers get used to it.
The rule: Filters get changed every 10,000 to 15,000 km. They cost less than 20 KM and the swap takes 15 minutes.
Electrical Issues
The LPG system depends on connectors, sensors, and wiring. Vibration, moisture, and heat take their toll.
What we see most: Oxidized connectors on the injectors, broken wires near hot engine parts, poor contact on the reducer temperature sensor.
From the shop: An Astra H. LPG randomly shuts off, check engine light on. Two months chasing a "software problem." Turned out to be a cracked connector on one injector losing contact over bumps.
Drifted Electronic Maps
The LPG ECU controls injection based on maps set during installation. Those maps match the engine condition at that moment. But engines change: plugs wear, coils weaken, compression drops. The maps stay the same while the engine does not.
How it shows up: Gradual consumption increase, mild jerking that worsens, check engine light.
The fix: Recalibrate maps at every LPG service. Five minutes of work, big difference.
Valve Seats - Older Systems
On older systems without sequential injection, gas went straight into the intake manifold with no precise mixture control, so valves took more punishment. On sequential systems this is practically eliminated.
Running an older system? Use valve protection additives or consider upgrading.
Prevention Is Always Cheaper
Every one of these problems is fixable. But the repair bill is always bigger than the prevention cost. A regular LPG service every 10,000 to 15,000 km catches most issues before they become faults.
If you recognize any of these symptoms, or have not serviced the system in a while, get in touch. We run diagnostics quickly and accurately.