Lly rail pressure

[timlb703]

05 lly I drive in winter has a loss in power above 2 k rpms. I logged it an rail pressure goes negative above 2k or full throttle. Bone stock. I shimmed rail no differance. Thoughts?

 

[02bigstrokin]

how many miles are on it tim? also are you running a lift pump on that truck?

 

[timlb703]

No lift pump. The only mod is a two year old tow tune. 125-130k miles. I did a fuel filter about 200 miles ago.

 

[Gmclbz]

How many miles on truck?

Nevermind...

 

[Stingpuller]

Lly

I have seen a rash of injector problems with lly's here lately. Hook up efi or a scan tool and ramp up your pressure at idle and see how high it goes. I bet it won't go much over 140 mpa. Then pull a hose off one side of the return and put it in a cup and see how much fuel it returns. One side should have 12 ml in 15 seconds. I bet the injectors are bad and returning everything. Jeff

 

[timlb703]

I have seen a rash of injector problems with lly's here lately. Hook up efi or a scan tool and ramp up your pressure at idle and see how high it goes. I bet it won't go much over 140 mpa. Then pull a hose off one side of the return and put it in a cup and see how much fuel it returns. One side should have 12 ml in 15 seconds. I bet the injectors are bad and returning everything. Jeff

It's funny you say that. I started driving a different 04 lly two days ago. it runs real strong. but smokes a little blue and smells strong. I was thinking injectors. I'm going to try this weekend what you suggested. I will log the other truck tomorrow.

 

[Burn Down]

Might look at the rail pressure sensor, I don't think it should ever read a negative while the truck is running...