very odd problem
 

i have a 99 cummins and when it sits for a day the batteries are grave yard dead. also when the batteries are good it seems to not get fuel (it just turns over) but if i hook a battery carger up it will fire right up. just replaced fuel pump and on my fuel presure gauge i am reading normal (15 psi) until i go to fire then it drops to 1 psi i am thinking injection pump. anybody else have any ideas? :argh:

Im thinking low side restriction

but the batterys are first issue, need solid CCA before anything else can be diagnosed
are your batterys in good state of health and have a parasitic draw or are they just bad?
one bad battery can take out the other so test them both carbon pile test or a load tester w/e is available to you
min cranking psi should be 7psi , clean filter and lines that are not kinked or restricted

does the engine run? after boosted?

with what you have said so far this sounds like a low side supply issue

good luck
scott:hellox:

The lift pump does not run while cranking so you will have low psi while starting. As long as psi is normal right after it starts your good.

ugg , bryce is 100% correct, I meant running psi not cranking psi, lift pump shuts down during starter engage sry for the misinformation:s:

but im still not convinced of a pump issue yet