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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), GMC Mechanic
Category: GM
Satisfied Customers: 29427
Experience:  GM Grand Master Technician 2007. 14 years experience.
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GM sierra 2500 hd: I have a crank no start duramax 2004. I

Customer Question

I have a crank no start duramax 2004. I have no fuel pressure. I pump the fuel filter and pressur build up and then go right down. FPR shhows 40000 on scan tool. Fuel rail pressure show 1.4 and target of 41
Submitted: 1 year ago.
Category: GM
Expert:  GM Tech (Cam) replied 1 year ago.
Hello, I'm Cam.
Can I get your first name please?
Sorry for the delay. Is yours a code 1 or code 2 engine?
Customer: replied 1 year ago.

Christian, Code 1 engine

Expert:  GM Tech (Cam) replied 1 year ago.
Ok, Find the 2 fuel lines on the rear drivers side valve cover. Take the smaller one off and attach your hose to the metal pipe coming from the engine. Put the other end into the container and Crank the engine to fill the line. Then empty out the container and keep the line full. Crank the engine for 15 seconds fully and measure the amount of fuel that comes out of that line. More than 24cc means the injectors have failed.
Customer: replied 1 year ago.

Done and no fuel comes out. The fuel tank is full

Expert:  GM Tech (Cam) replied 1 year ago.
Odd Christian, it should have some. Do you have a second person that can pump the plunger while you try to start it?
Customer: replied 1 year ago.

I did that today and i was able to start the truck when pumping and keep it running as long as I was pumping. As soon I stopped the truck stalled after 4-5 sec

Expert:  GM Tech (Cam) replied 1 year ago.
Ok so that means your injection pump has failed. There is a portion in the pump that draws fuel from the tank. There is an alternative, and that's to put in an aftermarket fuel lift pump system. I have not done one but I know they work.
Customer: replied 1 year ago.

Well my concern is when I press the plunger t pressurise the filter housing the pressure builts up then it goes away. Is this also related to a bad injector pump ?

Expert:  GM Tech (Cam) replied 1 year ago.
That is normal. It's not like a gas system that holds the pressure.
Customer: replied 1 year ago.

Any test I can do to confirm that ? this pump is pretty expensive.

Expert:  GM Tech (Cam) replied 1 year ago.
It is expensive, I know. The test I also do is to measure the vacuum reading when running and cranking but since it does not run, the injection pump is not pulling the fuel the only other test is to pump the plunger and see if fuel leaks out between the filter and pump. Oh that does bring one thing to mind. There is a small U shaped hose at the back of the injection pump that could be kinked and not sucking the fuel.
Customer: replied 1 year ago.

Ok, I did change the Injection Pump...5 hours and 1500$ pump and still the same issue

Expert:  GM Tech (Cam) replied 1 year ago.
Can I ask why you did not tell me this ahead of time?
Customer: replied 1 year ago.

I changes it after you tôle me it is the problem

Expert:  GM Tech (Cam) replied 1 year ago.
Ok I just saw it was only a couple hours after I asked and overnight no less. I am unable to continue. I will open this up for other experts.