A properly tuned LPG system runs so smoothly you barely notice the switch from petrol. If something feels off on gas, you are probably right. Here are the signs that calibration is off and why you should not ignore them.
Signs of Poor Calibration
The Car Jerks When Switching to Gas
Every LPG system has a switchover phase from petrol to gas, usually one to two minutes after startup. That transition should be seamless. If the car jerks, coughs, or RPMs drop noticeably, the switchover maps are not dialed in.
Jerking Under Acceleration
You press the throttle and the car jerks instead of accelerating smoothly. Classic sign the load maps are wrong. The engine is getting too much gas (rich) or too little (lean). Both cause rough running.
Unstable Idle
Sitting at a traffic light on gas and the RPMs bounce up and down. Or idle is steady but noticeably higher or lower than on petrol. Idle is the most sensitive operating condition and the first to show calibration problems.
Check Engine Light Only on Gas
Extremely common. Drive on petrol, everything is clean. Switch to gas, check engine comes on. Usually the lambda probe is reporting the mixture is outside acceptable parameters.
Many drivers live with the check engine light on gas for years. Bad idea. It means the engine is not running right, and over time that damages the catalytic converter and valves.
The Car Keeps Reverting to Petrol
The LPG system has a safety function that switches back to petrol if something is wrong. If this happens occasionally or regularly, the system is telling you there is a problem. Do not ignore it just because the car keeps running on petrol.
Why a Poorly Tuned LPG System Is Dangerous for Your Engine
Here is what most people do not know. Gas burns hotter than petrol. When calibrated correctly, that difference is minimal and the engine handles it fine.
But a lean mixture (too much air, not enough gas) pushes combustion temperature even higher. That stresses the exhaust valves and valve seats. Over time, it leads to valve damage, which is expensive.
A rich mixture (too much gas) means incomplete combustion, fouled plugs, extra load on the catalytic converter, and wasted money.
What "Properly Tuned" Actually Means
It means the gas ECU is precisely calibrated for your specific engine. Not a five-minute job with generic maps. You need to account for engine condition, injector type, operating temperature, and fine-tune everything to match.
At our shop we calibrate with professional diagnostics, monitoring parameters in real time at idle, partial load, and full throttle. The job is not done until every parameter is within spec.
If you recognize any of these symptoms, bring it in. Calibration takes an hour or two and can significantly extend engine life and reduce consumption.