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I have a 2001 Dodge 3500 cummins. For months now if I let the truck sit over night or weekend, I would have to crank and crank on it to get it started. Once started it would run great and start great unless it sat overnight or weekend. The problem started just if it sat over the weekend, but got bad enough towards the end that it would loose prime just while sitting during lunch break.

Three weeks ago it just died going down the road. I took it to dealership and they diagnosed a bad injector pump (understandable for 350k miles on truck). They changed it out and said it was ready. I came the next day to get it and still same hard starting problem, but started great after the first start of the day. They kept it and diagnosed saying my FASS lift pump was bad so they replaced it with another one and all new lines as well. Still same hard starting problem. They dropped the tank to make sure there was not a problem with the pick up tube or anything in tank causing problem but didn't find anything. Dealership has had my truck for 3 weeks, charged me almost $3k and truck still hardstarts for the first time everyday. I called today checking on it again and they are still testing stuff they said trying to find the problem.

Truck runs great but just doesnt act like the fuel is primed up the first time you start it each day. Dealership is scratching their head. Everything is new from the tank to the motor, lines, lift pump, injector pump, so the only thing else I could guess would be the injectors, but truck runs perfect once you do the first start for the day. Any ideas?

rebal

seems like there was some one hear that had that same problem, it ended up being a bad injector or injector tube.

Totallyrad

Somebody else posted a similar problem with starting a few weeks ago. His issue was a bad injector. I know it doesn't make sense that one injector was the issue but that's what he said.

mysterync

Connector tube o-rings are the cause most often.

BigIron70

Did they replace the overflow valve with the injection pump? If not you may want to run this test on it. Possible it is allowing fuel to drain from injection pump back to tank.

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 (Overflow Valve Location). 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.

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

j-fox

When mine did that it was the return line at the rear of the head.
Just like my 1995 did.
At first it didn't leak fuel out, just air in.

I would of felt guilty as all heck charging you $3,000 to slide that hose on a little farther.

Few of the dealers have diesel mechanics who understand them.
They are abundant in parts changers , though.