Lb7 starting trouble

[Pantz84]

hey everybody I'm new to the forum and first time durmax owner of a 03 lb7 Silverado. Im a mechanic but haven't done major work on diesel untill now. Shortly after buying my truck I noticed there was fuel in the crankcase so I started taking the valve covers apart and started with the passenger side. I got the passenger valve cover off, put feed lines back on, primed fuel and started the truck. No leaks there, so I moved to the driver side and did the same but now she won't start!. I bled and primed a dozen times because I figgered there was still air in the fuel but no matter how much I prime and bleed she won't start. What can I do?

 

[DAVe3283]

Fuel in the crankcase is usually a sign of cracked injector bodies. That is how the first generation of injectors tended to fail. You might not see them visibly leaking, depends on how bad it is. Or maybe it was just one on the driver's side.

For the no start, you will need a good scan tool that can log fuel rail pressure. During cranking, you need to see 10 MPa (I think, might be more) before the injectors will fire. I'll bet you aren't getting that. They can take a long time to prime, I've had to crank for 5 or 6 sets (hold key at start until the ECU turns off the starter) before it lit off.

I am not sure what you mean by bled the system. There isn't really a way to do that on the Duramax. All you do is keep pumping the primer until I gets hard, then crank. Repeat until it starts. Pushing on the fuel test port doesn't really help purge air. That port (by the alternator) is designed to test fuel pressure/vacuum, not purge air.

 

[Pantz84]

There is a plastic bleeder screw next to the bulb is what I'm refurring to. I figgered it might be visable do to the fact the crack case being over by 3- 4qts with fuel in about 6 days driving 24 miles each day for work.

 

[1ATony]

Thanks for joining

Tony