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Discussion Starter #1
i have a friend with a 1998.5 cummins that will not start unless you just keep cranking on it. he replaced the head gasket not to long ago and it ran fine after that. but now it will not start very easy and there is no visiable fuel leaks anywhere. does anyone have any ideas
 

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98 12-valve32 said:
i have a friend with a 1998.5 cummins that will not start unless you just keep cranking on it. he replaced the head gasket not to long ago and it ran fine after that. but now it will not start very easy and there is no visiable fuel leaks anywhere. does anyone have any ideas
Any error codes?

Then fuel leaks not aways are visable... Sometimes they leak air into the fuel system and allow it to loose prime.

Try re-repriming the system...
http://mopar.mopar1973man.com/2002 Dodge/Tips & Tricks/prime fuel system/prime fuel system.htm

If that helped the I suggest you do a fuel pump diagnostic...
http://mopar.mopar1973man.com/2002 Dodge/Tips & Tricks/lift pump/lift pump.htm
 

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Discussion Starter #4
the head gasket was replaced about 1700 miles ago. we have primed and bleed the system but it will not hold the prime. if you park it pointed down hill it will start fine.
 

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98 12-valve32 said:
the head gasket was replaced about 1700 miles ago. we have primed and bleed the system but it will not hold the prime. if you park it pointed down hill it will start fine.
AIR LEAK! Your loosing prime! :poke:
 

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98 12-valve32 said:
the head gasket was replaced about 1700 miles ago. we have primed and bleed the system but it will not hold the prime. if you park it pointed down hill it will start fine.
That was going to be my first question. Its the fuel return valve in the VP 44. I believe they cost about $75. what is happening is its getting stuck open and allowing all the fuel to drain back to the tank. When the truck is parked so the tank is higher than that valve, fuel won't flow back into the tank. Hope this fixes your problem.
Sean
 

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Discussion Starter #8
thanks, were is that fuel return valve at on the pump
 

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98 12-valve32 said:
thanks, were is that fuel return valve at on the pump
Number 4 in the pic... (Link below)
http://mopar.mopar1973man.com/2002%20Dodge/Tips%20&%20Tricks/VP44%20replacement/fuel-supply-fig23.jpg

Overflow diagnostic... (From the Dodge FSM)

Fuel volume from the fuel transfer (lift) pump will always provide more fuel than the fuel injection pump requires. The overflow valve (a check valve) is used to route excess fuel through the fuel return line and back to the fuel tank. Approximately 70% of supplied fuel is returned to the fuel tank. The valve is located on the side of the injection pump (Fig. 59). It is also used to connect the fuel return line (banjo fitting) to the fuel injection pump. The valve opens at approximately 97 kPa (14 psi). If the check valve within the assembly is sticking, low engine power or hard starting may result.​

If a Diagnostic Trouble Code (DTC) has been stored for “decreased engine performance due to high injection pump fuel temperature”, the overflow valve may be stuck in closed position. A rubber tipped blow gun with regulated air line pressure is needed for this test.​

(1) Clean area around overflow valve and fuel return line at injection pump before removal.​
(2) Remove valve from pump and banjo fitting.
(3) Discard old sealing gaskets.
(4) Set regulated air pressure to approximately 97 kPa (14–16 psi).
(5) Using blow gun, apply pressure to overflow valve inlet end (end that goes into injection pump).
(6) Internal check valve should release, and air
should pass through valve at 97 kPa (14–16 psi). If not, replace valve.
(7) Reduce regulated air pressure to 10 psi and observe valve. Valve should stay shut. If not, replace valve.
(8) Install new sealing gaskets to valve.
(9) Install valve through banjo fitting and into pump.
(10) Tighten to 30 N·m (24 ft. lbs.) torque.​
 
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