Hello all I'm obviously new here not new to cars I have tools and ability but I'm am lost on this. Sorry this will be a bit long. So my daughters car is a 2000 ml320 she was driving and it died. Crank but no start....... fuel pump did not seem to run could not hear the pump when turn key to 2nd pos. Tired a few times and heard the pump motor run once and car started for a few sec then died. Pump did not kick up again so no start. Had it towed home. So here is what's I've done. Replaced the fuel pump..... pump runs now but sill crank no start...... check fuses and relays all good (swapped replays and all fuses are are good). So I put a little gas in the air intake..... car starts up runs for a min then sputters and dies. So ok everyone on all these sites I read says it's the cps ( did make sense to me as the cps kills the spark but changed it with new bosh anyway) same crank no start..... ok so camshaft sensor maybe so I tested it... it's good.... ok so got a fule pressure gauge. Tested pressure at rail crank crank crank stays at a little more then 50psi. Ok so gas in intake starts up for about 30 40 sec. fuel pressure stays about 56/58psi when running on the gas in intake... so good pressure from what information I have read. So decided to over to see if something I am missing. I checked plugs (changed about 2 months ago) they are good. Checked wires all is good and checked coil packs they all spark strong. So I read and read and read all these sites all say pump crank sensor cam sensor fuel filter / regulator. So if it was regulator the fuel pressure at rail would not be be what it is or would jump like crazy ( it does not) fuel filter being bad would produce poor pressure as well. So I am stumped and I could just start throwing parts at it but I really do not want to do that. I have to be missing something. Also I have no codes. Any help would be greatly appreciated. So just to sum it up
good plugs.
good wires.
Getting spark.
new fuel pump.
New crank sensor .
tested cam sensor (good).
no codes.
Fuel pressure is 50 at crank no start (holds pressure after crank so not losing pressure)
When car runs with gas in the intake fuel pressure at rail comes up to 56-58 steady not loss and no erratic pressure fluctuations.

So what is it I am missing? Thanks.

 

I would say that your fuel filter is clogged.

How long have you owned the vehicle?