hey guys need your help / thoughts. 2002 lb7 with 246,000 miles on her. Had the injectors replaced under warranty at 186,000 miles, almost two years ago. runs good as daily driver, weak when pulling trailer, used edge attitude from friend does nothing. checked with tech 2. two weeks ago, rail pressure would only go up to 7100 psi when commanded even higher. this week, It will reach 8100 psi when commanded even higher. balance rates between -1.5 and +2.3. somebody said that balance rates wont be right if I don't have good rail pressure. how do I tell if it is the pump getting weak or the newer injectors bypassing up top. Is there a way to test the pressure straight off the pump? can I test the injectors myself like the dealer would for bypass. do I just buy a remaned pump from the dealer for 775 first because of the mileage on it. thanks guys. tony

You can do the bottle test for the FPR Fuel Pressure Regulator.

Brian

How long since you changed the fuel filter?

How long since you changed the fuel filter?

Definitely start here. Measure fuel filter restriction and consider adding a lift pump to relieve this restriction. We have a nice gauge to test the filter restriction. Just because the filter is new does not mean there is not a restriction somewhere.

http://www.kennedydiesel.com/detail.cfm?ID=289

Image at bottom of post.


You can do the bottle test for the FPR Fuel Pressure Regulator.

Brian

The bottle test is to test the fuel pressure relief (safety) valve. While this is an easy test and can be a common issue on the LLY and later engines it is not common issue and not an easy test on the LB7.



hey guys need your help / thoughts. 2002 lb7 with 246,000 miles on her. Had the injectors replaced under warranty at 186,000 miles, almost two years ago. runs good as daily driver, weak when pulling trailer, used edge attitude from friend does nothing. checked with tech 2. two weeks ago, rail pressure would only go up to 7100 psi when commanded even higher. this week, It will reach 8100 psi when commanded even higher. balance rates between -1.5 and +2.3. somebody said that balance rates wont be right if I don't have good rail pressure. how do I tell if it is the pump getting weak or the newer injectors bypassing up top. Is there a way to test the pressure straight off the pump? can I test the injectors myself like the dealer would for bypass. do I just buy a remaned pump from the dealer for 775 first because of the mileage on it. thanks guys. tony

The way to do this is to test the return fuel volume from the injectors. I think with as many miles as you have I would start with a fresh pump and see where that leads you. Consider a lift pump setup, better filtration, and a quality additive like FPPF Total Power to prolong fuel system component life.




As promised the fuel filter restriction gauge image:

http://www.kennedydiesel.com/images/Dmax-fuel-filter-rest1.gif

Thanks Kenndy Diesel for the info on that.

Brian

thanks kennedy for the advise. I will start with the pump first and then go from there.