Skoda felicia 1.3 mpi - Temperature sensor, radiator fan switch.

Hello.
Toy car skoda felicia 1.3 MPI 1998 from lpg 2nd generation.
I have a problem with the temperature sensor in the thermostat and the sensor in the radiator, it is a fan switch.
I have long suspected that the sensor in the radiator (two-pin) around the air filter is working incorrectly.
The car was behaving strangely. At lpg it had no power, it was not trading.
Choked. It was a bit better on gasoline.

When the engine is warm, the fan on the radiator switches on.
The DeltaSCan diagnostic program then shows the temperature of one hundred or several degrees.
This is the moment of starting the fan.

I did a small test.
I unplugged the plug from this sensor (in the radiator) and bridged the wires.

Symptom:
- when the ignition is off without the key in the ignition the fan turns on the radiator,
- also on when the ignition is on.

1) Does this clearly indicate damage to the sensor (in the radiator) or its malfunction?

2) After unplugging the temperature sensor from the thermostat the car works very well.
Quite differently, it works more frankly.
Despite unplugging, the fan turns on as the temperature rises.
Can you drive without this sensor plugged in until replacement?
Can you check it by bridging the wires like this one on
cooler?

3) I encountered temperature sensors with a yellow and blue stripe.
What does this color mean?

4) Does the temperature sensor affect the correct engine operation so much?
Why working on gas is worse with a damaged temperature sensor, and on
gasoline better?

Best regards.

1. No. This indicates that the entire fan circuit is functional. The sensor in the radiator is a thermal switch, so it works zero-one. Since it turns on the fan after warming up the engine, it sure is good.
2. The sensor in the thermostat is a thermistor, i.e. it gives information smoothly about the changing temperature. The easiest way to diagnose it is to look in the morning at what fluid temperature the motor controller sees. Then after firing, the temperature should rise as smoothly until the thermostat opens. You can also remove its characteristics with an ohmmeter, in a pot with heated water. The line connecting the characteristic points should be smooth. This is often a hyperbola. Shorting this sensor will do nothing.
3. Usually colors represent different characteristics / types of sensors.
4. The temperature sensor is one of the main sensors when it comes to calculating the fuel dose, revolutions etc. When you disconnect it, the controller must take some value for the calculation. Some take the temperature of a heated engine (then it's hard to start the engine), and some temperature of the cold engine (then warm has more power).

IIgen installation. works independently of gasoline. In general, the rule is this. If the engine does not work properly, turn off the lpg (turn off the valve on the cylinder) and drive on gasoline. Only when it is correct on Pb, do we regulate lpg. Read also about fuel corrections and broken maps when driving on gas.

Thanks for the info.
I replaced the engine temperature sensor (in the thermostat). The O-ring was torn, and the sensor, heavily soiled, sediment etc. It seems to be better, but sometimes it can get hiccups on lpg.
I also replaced the new liquid phase filter. There is no rule when he gets hiccups.
As if something blocked him to enter over 2 thousand. rotation. Because above this limit can not hit.

I also noticed that sometimes on gasoline turnovers (tips) stop at 2 thousand. stand, just add gas slightly and return to normal.

The damper was cleaned, the adaptation was.
Does the mapsensor bow?
Best regards.