The Car Care Clinic with the Dr John

1997 Chrysler - Petrol flooding

Larry from Dorking

Question

Would you explain what could be reasons for petrol flooding an engine and how to start the car if flooding has occurred? I have a 1997 Chrysler

Answer

Larry, a flooded engine is an engine that has received too much gas for the amount of oxygen available for combustion. When this condition occurs the inside of the cylinders, as well as the spark plugs, will become wet with gasoline. A cylinder wet with gas will result in a reduction of cylinder compression, loss of lubrication to the piston and rings and cause spark to the spark plug to be misdirected.

Because the large majority of engines on the road today are fuel injected we’ll cover how to start them if flooded. The computer has a program in it that is called the Clear Flood Mode. For the computer to activate the Clear Flood Mode it needs to see information that is out of the norm. This abnormal information is the sensor on the throttle reporting to the computer that the throttle is being held wide open, along with a crank signal to the starter.

This combo of information causes the computer to respond by reducing, and in some cases completely shutting off, the fuel injectors. This process allows air only to enter the cylinder and dry out the abundance of gas. As the correct balance of air and fuel return you will feel the engine start to fire at which point the throttle can be released and the computer will return to normal fuel delivery.

Good Luck!
Dr. John