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Diagnostic Chart:

Engine Cranks But Won't Start:

In order to diagnose this system, battery voltage must be above 11 volts. Cranking speed of the starter must be normal and fuel quality should be checked. When ignition is On and crank pulses are received, the ECM grounds the primary side of each of the six coils to fire spark plugs. Also, the injectors will fire when crank pulses are received.

DIAGNOSTIC AIDS
Water in fuel can cause a no start during cold weather starts.

An ECT sensor reading incorrectly can cause a no-start or a hard start. This may be due to over-fueling or under-fueling.

ECT may be compared to IAT with Scan tool if engine has cooled overnight at ambient temperature. They should be within four degrees of each other with ignition On and key Off.

TEST DESCRIPTIONS
1. If an injector fuse is open, all six injector DTCs Will set when the engine is cranking.
2. If the 5 volt reference circuit becomes shorted to ground it will result in a no start.
3. An IC module fault will cause at least one cylinder to not spark and may result in a no start, especially if engine is cold.
4. An EGR stuck open may result in a no start.
5. If no rpm is indicated on Scan tool, spark and injectors will not be turned On.
6. Under normal cranking conditions the 58 counter should count up to 85 or 170 (two cranking revolutions) and reset to zero when a cam pulse is received.
7. Check for a flooded engine.

IMPORTANT: Always check fuses first in the LIPFB, RIPFB and UHFB.