1994 GMC Suburban Owner's Manual - Page 253

Water in Fuel Sometimes, water can be pumped into your fuel tank along with your diesel fuel. This can happen if a service station doesn't regularly inspect and clean its fuel tanks, or if it gets contaminated fuel from its suppliers. If this happens, a "WATER IN FUEL" light will come on. If it does,the excess water must be drained. Your dealer can do this for you. This light also should come on briefly when you start your engine, as a check. If it doesn't, have it fixed so it will be there to let you know if you ever do get water in your fuel. If the light comes on at any other time, use this chart. "WATER INFUEL" LIGHT CHART Problem Light comes on intermittently. Light stays on: 1. At temperatures above freezing. 2. At temperatures below freezing. Recommended Action Drain water from fuel filter. Drain fuel filter immediately. If no water can be drained and light stays on, see your dealer forassistance. Drain fuel filter immediately. If no water can be drained - water may be frozen. Open the air bleed valve to check for fuel pressure. If no fuel pressure is present, replace the fuel filter. Fuel tank purging required. See your dealer for assistance. 3. Immediately after refueling large amount of water possibly pumped into fuel tank. Hesitation or "flat" performance at high speed or during hard acceleration may be an indication of premature fuel filter plugging due to dirty or contaminated fuel. The filter element may need to be changed if this happens. See your dealer for assistance. NOTICE: If you drive when this warning light is on, you can damage your fuel injection system and your engine.the light comes on right If after you refuel, it means water was pumped into your fuel tank. Turn off yourengine immediately. Then, have the water drained at once. 6-7