I got a 2001 duramax good old lb7 and weeks of reading and here's a question if your cp3 goes bad can a lift pump do the job of fuel delivery and just instull it with out changing the unit .. And for a newbee I don't have a lift pump right thank you
New to duramax but loving it
- Thread starter Terrellsherilyn
- Start date
Welcome
To answer your question, no, a lift pump will only supply the cp3 with clean and a ready volume of fuel at a pressure of somewhere around 8-14 psi for a dmax, from there the cp3 pressurizes the fuel to upward of 22,000-28,000 psi (depending on tuning and modifications) in stock trim the factory set up the cp3 to pull fuel all the way from the tank through the fuel filter and then it did its true job, which is to pressurize the fuel and deliver it to the injectors. So by adding a lift pump with dual filters, you clean the fuel, remove the air and potential water and then deliver the clean fuel to the cp3, eliminating the work load of the cp3 and thus increasing its life. So again, to answer your question, no adding a lift pump won't fix or bypass a bad or weak cp3, although I'm not sure if it wouldn't prolong the complete failure of the cp3 itself?
Hope that helps :thumb:
Welcome to DD
what leads you to believe you have a bad cp3?There are other things that mimic a bad cp3.
what leads you to believe you have a bad cp3?There are other things that mimic a bad cp3.
Well when I first bought the truck ,the truck would crank for at least 10 sec and some times I would have to prime the filter pump but the pump wasn't working that well so I put a pump rebuilt kit in and new filter in and now truck starts great so I'm hoping all is good for now the truck seams good but I now the LB 7 do have a bad run of injectors and just now sure If I should take to dealer to just take a look at it to make sure all is good
Also my fuel guage turns off all the time on for a few miles then off then on then off after 7/8 tank offffffff I would think the sending unit is bad right
Could be the sending unit but it could also be the stepper motor in the dash,it could also be a bad ground or a loose connector.
