I have a 99 integra, and recently it has been acting up. In a cold start it's starts with ease. But when engine is in operating temperature it does not start just turns over. And a smell of fuel and other smell comes. What could be the cause of this?

 

This sounds like a Bad ECT coolant temp sensor, as the engine starts cold the ecu compensates fuel to the engine to idle, it usually will run rich during this period and as the engine warms up the ecu cold start compensation will shut off and the sensor will send the engines temp and the ECU will adjust the fuel. When the sensor is bad the ECU will not know what AFR to give and will not operate. Start with that sensor, test and replace if needed.