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gonzo 1066

2007 stock lift pump pressure

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I have a 2007 5.9 in the shop with hard or no start issues (most of the time)       It has the in tank stock lift pump, It seems to flow a lot of fuel with the line after the fuel filter disconnected I test about 9psi at the engine.   Is that typical?   

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4 hours ago, gonzo 1066 said:

I have a 2007 5.9 in the shop with hard or no start issues (most of the time)       It has the in tank stock lift pump, It seems to flow a lot of fuel with the line after the fuel filter disconnected I test about 9psi at the engine.   Is that typical?   

 

I believe so. When I customized my intank stock pump setup I looked at a bunch of things. Just above that pump is a run-around check valve that limits  pump output to 9psi if I remember exactly. The pump is capable of putting out much more pressure. I removed that check valve and measured I think 22psi at the filter with just the intank pump and engine at idle. My current setup is the stock intank pump with that valve removed feeding a mechanical pump driven off the crankshaft, then into a pressure regulator with a new return line back to the tank. Then from the regulator to the factory filter/water sep, then into a Caterpillar 2 micron filter then the CP3.

 

I'm the farthest thing from an expert on diesels. Could it be the FCA in the CP3 is bad? They can act strange when going bad. What about if the pressure relief valve on the rail is stuck open?

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Hey Bob the FCA is the other thing I was thinking about when we talked but I couldn't remember what it was called?????? CRS for me when it comes to common rail trucks because I never owned one until my 14. 

I don't think the pressure relief valve is stuck because 7 out of 10 times it starts and runs fine then it will hard start and run poorly. 

He cannot hear the pump running the other 3 out of ten times. 

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I’ve seen weak pressure relief valves cause this issue. 

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I have not run codes yet,  I am going to start isolating injectors to see if there is a faulty one.   The fuel pressure blockoff is coming tomorrow.   Hope between these two tests I will get closer to the problem.   

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codes will help with the direction of your troubleshooting.   the tubes that connect the hard line to the injector inside the head can come loose, causing symptoms like yours. have you done an injector return test? i would do that before testing them  seperately.

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