Why Doesn’t My Car Switch to LPG?

 

 Why Doesn’t My Car Switch to LPG?

The 7 Most Common Reasons and Their Solutions

Today, many drivers prefer LPG-powered vehicles. These systems are both economical and environmentally friendly, but occasionally they can cause certain issues.

In this article, we address a frequently asked question in detail:

“My car runs on petrol but doesn’t switch to gas (LPG). Why?”

Here are the 7 most common causes of this issue and how to fix them:

 

1. Delayed Automatic Switch When Engine is Cold

LPG systems typically activate only after the engine reaches a certain temperature.

Symptoms:

• The car remains on petrol longer in the mornings
• It switches to gas after warming up

Solution:

• This is normal—it’s a feature to protect the engine.
• However, if it takes too long, sensors or temperature settings should be checked.

 

2. Faulty LPG Regulator (Reducer)

The LPG regulator converts liquid gas into vapor for engine use. If it fails, the switch can’t happen.

Symptoms:

• Car stalls when switching to gas
• Jerking or choking during switch

Solution:

• Have a professional check pressure and temperature values of the regulator
• Replace it if needed (costs approx. 1000–2500 TL)

 

3. Faulty Sensor or Temperature Sender

LPG systems use temperature sensors to decide when to switch to gas.

Symptoms:

• Car doesn’t switch to gas even when warm
• LPG light keeps blinking without switching

Solution:

• Replace the faulty sensor or sender
• These parts are usually affordable (approx. 200–500 TL)

 

4. LPG ECU (Electronic Control Unit) Error

A software or hardware malfunction in the LPG ECU can prevent the system from working.

Symptoms:

• Engine stalls immediately after switching to gas
• LPG system completely unresponsive

Solution:

• Have the software updated by a certified LPG technician
• Replace the ECU if necessary

 

5. Empty LPG Tank or Poor Gas Quality

A common but overlooked issue: the tank may be nearly empty or contain low-quality gas.

Symptoms:

• Engine struggles to switch
• Stays in petrol mode constantly

Solution:

• Refill at a different station with quality LPG
• Check gas level—gauges may sometimes be inaccurate

 

6. Dirty or Malfunctioning LPG Injectors

LPG injectors may clog or wear out over time, blocking proper gas delivery.

Symptoms:

• Jerking when switching to gas
• Rough idling or stalling

Solution:

• Clean or replace the injectors
• Using quality LPG reduces this risk

 

7. Electrical Connection Problems

Loose cables, faulty connectors, or blown fuses can disable the LPG system.

Symptoms:

• No light on the LPG button
• No switching or system response

Solution:

• Inspect wiring, connectors, and fuses
• Often a quick fix by an electrician or mechanic

 

When Should You Visit a Service Center?

Consult a professional LPG service if you experience:

• No gas switching at all
• Engine stalls while switching
• No light on LPG control button
• Smell of gas (seek service immediately!)

 

Summary Table: Common Issues and Checks

Problem	What to Check
Cold engine	Normal – wait a little
Faulty regulator	Consult LPG specialist
Sensor malfunction	Replace or calibrate
ECU failure	Software update or replacement
Empty or bad gas	Refill with quality LPG
Dirty injectors	Clean or replace
Electrical issue	Inspect wires and fuses

 

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