2005 lly

[nitrochad]

Hello I am looking for help with my truck. Truck idles fine. Starts out fine. But once it gets warmed up it sounds or feels like a miss. No codes. Fuel filter changed. Without codes I have no idea were to start. 124,000 miles on truck

 

[2004LB7]

Do you have a scanner that can monitor pids?

 

[nitrochad]

Yes

 

[2004LB7]

Measure and report:

Desired fuel pressure
Actual fuel pressure
Main fuel rate mm3
Balance rates in park and in neutral
Air flow in grams/second before and after running rough
Engine temp before and after it start to run rough
Air temperature
Crank and cam sensor missed pulses

 

[nitrochad]

I am thinking it's the fuel psi regulator. I will get u the numbers you are looking for. Idles fine. Balance rates are good. Max 4 on #1

 

[2004LB7]

Very well could be. It's a common cause of rough idle

 

[nitrochad]

Nothing wrong with idle.

 

[2004LB7]

Inspect the harness where it run by the alternator. Also try the ice pick trick or new pig tails on the injectors. Particularly 2 & 7

 

[nitrochad]

Ok.

 

[nitrochad]

Pictures

 

[nitrochad]

Pictures. Injector balance rates are from 0 to a max of 3 on #1 cylinder all the others are lower. Just cruising along frp actual and commanded is 70, truck runs fine.

 

[nitrochad]

Pictures. Injector balance rates are from 0 to a max of 3 on #1 cylinder all the others are lower. Just cruising along frp actual and commanded is 70, truck runs fine.

 

[2004LB7]

Are you sure you don't have air in the fuel line? Or perhaps a collapsed fuel hose?

 

[nitrochad]

No idea. Truck has a 124,000 miles

 

[2004LB7]

It's also 18 years old. You may want to replace the rubber fuel lines on the engine. You can use a clear test hose after the filter to see if you have air in the line

 

[1FastBrick]

No idea. Truck has a 124,000 miles

Mine is under 130K and I can tell you the rubber fuel lines on mine are starting to crack. Take a closer look at yours.

 

[nitrochad]

Which lines?

 

[Bdsankey]

Measure and report:

Desired fuel pressure
Actual fuel pressure
Main fuel rate mm3
Balance rates in park and in neutral
Air flow in grams/second before and after running rough
Engine temp before and after it start to run rough
Air temperature
Crank and cam sensor missed pulses

This!

Plus check to make sure the FPRV is not opening prematurely via a bottle test.

https://kennedydiesel.com/docs/Shim%20mod%20Bottle%20Test%20etc.pdf

 

[nitrochad]

I put new relief valve in.

 

[Bdsankey]

I put new relief valve in.

Ok, but did you confirm it's not leaking/bypassing fuel? New parts fail, can be installed incorrectly etc.