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2000 Dodge Ram 2500 Question: Wont Start

 

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Ram It, Diesel, Newark, OH, December 12, 2009, 18:06
 Rookie

The engine will crank over but it will not start. The lift pump has been checked out and is good but when you turn the key on the lift pump doesnt come on...The ignition switched as been checked and it is also good..Please Help..

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  • Answer #1

    mahindra December 12, 2009, 19:10
     Journeyman

    Vehicle: 1999 - 2002 Dodge Ram 2500 Pickup 5.9L



    Symptom: Information for a no start diagnosis.



    System: Emissions/PCM/Fuel



    Codes: N/A



    Problem: Information on the importance of immediately checking fuel delivery for a no-start diagnosis.



    Test & Fix: This information applies only to the 24-valve electronic diesel fuel injection system. It is important to check for proper fuel delivery immediately when diagnosing a no-start complaint. The injection pump uses the extra fuel delivered by the transfer pump for cooling and lubrication. A common problem occurs after a failed transfer pump or a clogged fuel filter is replaced. Extended cranking with inadequate fuel delivery to the injection pump may cause damage to the injection pump causing a no-start after proper fuel delivery has been restored. The transfer pump is duty cycle controlled by the Engine Control Module (ECM). It operates at two different duty cycles depending on conditions. The ECM will run the transfer pump at 25% duty cycle while cranking the engine. At 25% duty cycle, the transfer pump should deliver fuel at 7-12 PSI to the injection pump. The transfer pump is run at a lower speed to lower the fuel pressure at the injection pump fuel inlet until the engine is running. Anything more than 14 PSI may cause a hard start. If the starter is engaged and the key is released from the start position without starting the engine, the ECM will run the transfer pump at 100% duty cycle for 25 seconds after the key is released. The fuel pressure should be above 10 PSI during this 25 seconds of transfer pump operation. Also check the volume of fuel by removing the fuel line at the fuel filter and connect one end of a clear tube to the transfer pump side. Put the other end of the clear hose into a clean 1 gallon container. Bump the starter with the key to run the transfer pump for 25 seconds to bleed the air out of the clear hose. Turn the key off when the transfer pump stops and empty the 1 gallon container into an appropriate waste storage container. Turn the key on and bump the starter to run the transfer pump for 25 seconds again to check the volume and for air bubbles in the fuel stream. Volume should be at least 45 oz. of fuel in the 25 seconds of transfer pump operation. There should be no air bubbles in the fuel stream. If there are any air bubbles, check for a loose fitting or a cracked hose or fuel line between the fuel filter and the fuel pick up tube in the fuel tank. After the engine is running, the ECM runs the transfer pump at 100% duty cycle and the fuel pressure should be 10-14 PSI.

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