I just finished building a new 6.0 LQ4 for my truck. It has 90 miles on it with light to medium throttle, never over 4K RPMs. Today it threw 4 codes and began missing, such that it wouldn't even pull it's own weight. After a minute, it came out of it and ran ok. Turn it off and restart it, and it missed badly with any throttle input for a minute, and then comes out of it. After 1/3-1/2 throttle, it runs out of power. Below that is good.

Here are the codes.
P0171 - Fuel Trim System Lean Bank 1
P0174 - Fuel Trim System Lean Bank 2
P0131 - H02S Circuit Low Voltage Bank 1 Sensor 1
P0151 - H02S Circuit Low Voltage Bank 2 Sensor 1

It turns out that it was tuned for 8.1 Marine injectors instead of 8.1 truck injectors. What are the chances that my engine's hurt from running too lean?

 

Slim if u dident hammer on it to hard. But 8.1 injectors? what are those stock 28#? All u need is the stock ls1 style inectors and scale them. 36# should do u fine. Are u sure the fuel pressure is on point?

 

32# I believe. It never saw more than 1/3-1/2 throttle. I'll check the fuel pressure tomorrow. I pulled all the plugs this evening and they look good.

 

I never ran something out of gas a few times and experienced any noticeable damage. I even ran lean down the track at WOT a time or 2, and don't think it hurt anything. I think you'll be OK, it's generally extended lean runs at full throttle or heavy loads that can cause the long term damage, I'd think anyway...

 

Here's a vid of what it's doing when you first start it. When hot, it doesn't come out of it this fast. You can hear it cutting out and back firing when I give it a little throttle. It did not do this for the first 70 miles on the engine. This is what started on the interstate when I got on it about 1/2 throttle and kicked it down. Learning about the tune problem is what came out of this. I'd like to know why it's doing this now though. This is after having the batter unhooked for several hours. It does it in both open and closed loop.

http://www.youtube.com/watch?v=fnQPhsC_2pk

 

Seems more to me like a transmission problem since evrything is good with it in nuetral, but when you put a load on it it struggles. Maybe an issue with the TC?

 

It's definately the engine cutting out and back firing.

 

Anyone have EFI Live, v1 or v2, that they'd want to sell?

 

Get it checked properly mate, check your fuel pressure and all the ecu grounding points. Will give problems like this at any given time. Then throw money at it. Once you make sure everything simple is checked

 

Fuel pressure is 52-54 at idle. Pulled the regulator vac hose, and it jumps to 58-59. Turned engine off and it holds pressure.