I recently bought an 02 2500HD with LB7. I have had it for a couple of months and has run perfectly, no problems at all. My wife is leaving across the state for Easter weekend, so I thought i would check things out, change oil and filters, and lube things up before she goes. I have a problem now that i changed the fuel filters, I say filters because the old owner installed a 2 micron prefilter in line, at the fuel tank under the truck. i must not have got all the air out when i primed the system from the factory filter, because after i started it back up it ran for a minute or so then died. I reprimed the system and restarted it. The problem is now it sounds like Rods knocking, I know its not but the engine is running real loud compaired to normal. I thought well maybe There is still air in the system, so I let it run for a couple of min. thinking it may work itself out. but the noise and poor running is still there. I also notice when i turned it off that the service engine light had come on.

Could I still have air in it? I am getting solid fuel from the bleader. and it ran great before the filter change.

Could the brief moment it ran dry on fuel caused a rpoblem with the injection pump?

Running it out of fuel should not have done any permanent damage. I've run my truck out of fuel far too many times, and it has never run any different once I get it fired back up.

I'd get the CEL code scanned, and post that up here. Good luck!

Running it out of fuel should have o effects on the fuel system i have ran my truck out of fuel a few timebefore and she still runs like a top my guess is it maybe bad fuel bit i highly doubt it.
i would really get that code scanned and post it up here it would really help!

Thank you Very much for the reply's. I went out this morning and dove into this problem with the idea that i was still getting air in the fuel system. I started with the prefilter making sure the seal was good, that was not it, I replaced the oring on the bleader screw, I started it and that was not it.
I dissasembled the primer to check the seals and o-ring, The o-ring at the base looked some what flat and a posible source for an air leak. I repaced it and it is Running great now. The trouble code was my fault. I forget off the top of my head the Number, but it was a Mass air flow code, due to me test running it with out the air filter on. I washed it out and was letting it dry.
I just want to say thank you for spending your time to help people out. I can't wait to be able help someone with my experiance's.:)

Thank you Very much for the reply's. I went out this morning and dove into this problem with the idea that i was still getting air in the fuel system. I started with the prefilter making sure the seal was good, that was not it, I replaced the oring on the bleader screw, I started it and that was not it.
I dissasembled the primer to check the seals and o-ring, The o-ring at the base looked some what flat and a posible source for an air leak. I repaced it and it is Running great now. The trouble code was my fault. I forget off the top of my head the Number, but it was a Mass air flow code, due to me test running it with out the air filter on. I washed it out and was letting it dry.
I just want to say thank you for spending your time to help people out. I can't wait to be able help someone with my experiance's.:)

So the prime was the problem huh. well good to hear you got it running great again.
The MAF code is P0101 i know ive gotten it many times, think everyone in this forum has gotten it at one time or another:D but if you get the code again it maybe a good idea to clean the it but when you do be VERY careful just buy some MAF cleaner douse it and let it air dry like i do, do not blow it out with a compressor you will most likley destroy it and they arent cheap to replace

Yeah Ive been there on a corvette... Spendy... Thank you again

I'm curious...do you have a size for that o-ring?

Yea, MAF cost like 587 bucks, I just bought one..............................

Thank you Very much for the reply's. I went out this morning and dove into this problem with the idea that i was still getting air in the fuel system. I started with the prefilter making sure the seal was good, that was not it, I replaced the oring on the bleader screw, I started it and that was not it.
I dissasembled the primer to check the seals and o-ring, The o-ring at the base looked some what flat and a posible source for an air leak. I repaced it and it is Running great now. The trouble code was my fault. I forget off the top of my head the Number, but it was a Mass air flow code, due to me test running it with out the air filter on. I washed it out and was letting it dry.
I just want to say thank you for spending your time to help people out. I can't wait to be able help someone with my experiance's.:)

Where did you get the replacement o-ring for the primer? Is that all thats in those things?

I have a Universal o-ring kit, both metric and standard, and im sure over the years i have probebly mix them all up. I just found one that worked, i checked to see if I had another to measure it out, but it must have been the only one left.
When you pull the three torx screws from the primer cap and remove it, you will see a plastic sleeve with two cup seals and a spring. If you wiggle the plastic sleeve from the filter housing you will find the O-ring that fixed My problem.

Yea, MAF cost like 587 bucks, I just bought one..............................

OUCH!!!! bet that left a mark

Where did you get the replacement o-ring for the primer? Is that all thats in those things?

These are suppose to work

https://ecommerce.hydrapakseals.com/eShop/%28S%28rmvbz3vbgnhqsfjl4cxnxg45%29%29/default.aspx?ControlName=ItemDisplay&item_id=8554aca3-bba1-4e51-82ba-f40fde103b62&category_id=A2D23C7B-48B0-4506-9105-BAAD6E88EEB6