2 - Sufficient Clean Fuel

2. Sufficient Clean Fuel







Purpose:
The purpose of this test is to see if the fuel system is getting sufficient clean fuel to operate correctly.

Recommended Procedure:
Route a hose from the fuel drain line to a clear container and open the drain. Idle the engine and observe the fuel flowing into the container. Shut the engine off when the container is half full.

Observe WATER IN FUEL light while cranking. If the lamp is illuminated the fuel is probably contaminated with water.

Flow out of the drain should be a steady stream. Insufficient flow could indicate fuel supply or fuel system problems.

Inspect fuel in the container, it should be straw colored but not cloudy. It also should be free of water and contaminants. Dyed red or blue fuel indicates off-highway fuel.

If engine oil is present in the fuel it may indicate an injector 0-ring leak and subsequent loss of rail pressure. If that is suspected, check rail pressure during engine cranking (refer to Hard Start/No Start Diagnostic Procedures Step 9C). Hard Start/No Start Diagnostic Procedures







Some sediment and water may be present in the fuel sample if the fuel filter has not been serviced for a prolonged period of time and/or if the sediment and water have not been drained recently. If that is the case a second sample may be required to determine fuel quality.

Possible Causes:
- No fuel in tank.
- Fuel supply line could be broken or crimped.
- Fuel could be jelled (most likely in cold weather with No. 2 fuel).
- Pickup tube screen in tank could be clogged.

Cloudy fuel indicates that the fuel may not be a suitable grade for cold temperatures. Excessive water or contaminants may indicate that the tank and fuel system may need to be flushed and cleaned.

Tools Required:
Clear container - approximately 1-quart