Strange false detected overheating

I have very strange problem with my cooling system.
After some driving, when the temperature of the coolant is normal, engine stops in idle mode. And I can't start the engine until the coolant if chilled. Then I can drive the car until next heating... I changed the temperature sensor near thermostat but it didn't help. If I start the engine and didn't move and heat the engine to the critical temperature, main radiator fan didn't start. Dashboard is working normally- real temperature is shown. Check engine lamp didn't light up.

Maybe there is other temperature sensors on this engine?

Please help me with my car. There is summer outside and I can't use my car :)

You are not going to get very far towards correcting the problem in this manner. :nono:

You say: After some driving, when the temperature of the coolant is normal, engine stops in idle mode.:eek7:

Unless I'm reading this wrong, you are telling us that everything is normal, and the van just dies at idle. Nothing there indicates you are having an over temp issue. It would really help if you mentioned the year of the van too. The fans don't come on until the engine is pretty hot--210 to 220 I believe

There are many reasons this van will die at idle, temp is not a very likely one.

Good reply, agreed on every point.

Sorry if you didn't understood. English is not my native language. Nor the second...

While engine is cool, engine works in idle mode fine. When the temperature of the engine is normal (normal according to dashboard) engine stops. Also, I can't start the engine if it is normal termperature. When it cools down, (lower than working) I can start the engine.

Also, when I mean high temperature, this means that dashboard termometer is in the most right, red zone. This means critical hot. And fan is not starting.

If the engine is cold and I disconnect temperature sensor connector, fans starts to spin at high speed. So, the fan motors are OK.

I changed sensor on thermostat.

It looks like electrical problem in relays, computer, wires...

Engine: 3.4L, 1998 Venture.

If you unplug the ect (engine coolant sensor) the pcm should read that as a very cold engine, -39 C and rather than start the fans, it should set the MIL light within 3 seconds.
The sensor (located right near the water thermistat where the top hose from the radiator connects) is a thermistor which allows the voltage to rise as the temp rises.

If you get no code set when the temp sender is unplugged, it may mean you have a bad PCM. I don't like to jump to conclusions like that, but bad wiring wouldn't keep the code from being set when unplugged while still causing the fans to come on.
Fans are controlled by the PCM.
Not sure how much change there is from '98 to '99, my book & van are '99, but I have a '92 as well and its pretty close to the '99.

The MIL light does come on when the car is stalled doesn't it? If not, you should start suspecting a bad PCM.

New data :)

We unpluged ALL possible sensors and checked situation. We found one sensor on engine oil pan. It is maybe designed to detect oil level. But we changed it, and engine is working! (Oil level is normal) Or it is oil temperature sensor?

Now I can drive my car, but there are still other problems. Also, I have random "check engine" lights...