2002 Safari, new fuel pump last year. Fuel pressure test show 50 psi..still wont start. It cranks until the battery dies. Every now and then it chugs like it wants to start but sputters and stops. Let it sit for a week...then it starts and runs ok. Try to start it later that day or the next day...nothing.

IS Australia, (USA answers me)
and now we know 3.6 L Alloytec (LY7) V6 engine, by GM. (chain drive.DOHC cams)
2004 first one.
you say spark is good but to all 6 cylinders or just 1.?

that is normal, for PUMP,
key on may run pump for 1 to 3 seconds, called PRIME,cranked pump runs full time cranked by designand engine running pump runs full time so all that is normalsome pumps are silent running and BOSCH makes those and brags about it. yeah nice so a tech uses 2 tools ! always
a voltmeter at pump 11v min, (wires drop 1v) as does starter load.
and a fuel pressure gauge. or it's all just a guessing game.
now rule #1 ALL PCM cut fuel 1 or 2 ways if spark or its precursors are detected as FAIL (by law and to end crash and burn seen on TV)
3 ways top fail cmp,ckp or coil packs dead , make spark dead. and more lots more. even spark wires old.for sure those carbon core junk.
so spark is first NEVER FUEL FIRST.
I test all spark HV wires with new test park plug, grounded

also SOME failures fool the PCM in to thinking spark is good and is not.but we all know the PCM is not AI or genius grade yet.
no year car told but is 2004 up. to 2007.
engine size, 3.6L petrol (gasoline) and VVT,
how many miles on the engine, 300k miles or 500Kmeters?
The VVT can file. as can chain guilds.
VVT can fail and case 50degrees of error at cams, cranking , not good that.

Now spark failures, on high mileage engines, there ar 6 COP spark coils to fail
and spark plugs too, over 100kmiles.
the cops have 6 boots that love to age crack and spark cause carbon tracking that shorts out dead the spark plug ,new boots are $15 each 10x cheaper than new coils with boots. (a cost savings Idea)
spark is good only when all 6 are good.
that is all I can say on 2004 car, many have super high mileage.

Could my fuel pump be bad ????? Rather then guessing , i suggest you test fuel pressure to know for sure . Videos on youtube showing how . You will need to buy a fuel pressure testing tool . (55-62 psi) VIN: (V, T,U)

Lacking in fuel pump pressure,.

When you turn the key to on, not start, do you hear the pump turn on for a couple of seconds to pressurize the fuel system? If you do, check fuel pressure with a gauge, should be over 50 psi if multi port injection, about 20 psi if throttle body injection. If pressure is good, you may need to check the fuel injector circuit.
If no sound from the pump, you will need a voltmeter or a test light to check the fuel pump circuit. First check the fuel pump fuse. Then check for power at the gas tank on the fuel pump wire, when the engine is being cranked over. Power should be going to the pump then. If nothing, move back to the fuel pump relay-need to check for power at the relay.

You could have a fuel delivery problem. I would recommend to start by checking fuel pressure. Fuel injected cars are very fuel pressure sensitive. Fuel pressure is very important and must be within specifications! But if the pressure is low, it does not mean the pump is bad. A plugged fuel filter, a pinched line, and low voltage at the pump can contribute to low fuel pressure. All three must be check before replacing the pump! You can get a fuel pressure gage at a local auto parts store for cheap. Fuel pressure testing is frequently overlooked but it is one of the common causes of poor performance. The test procedure must include testing that will insure normal fuel pressure under all operating conditions. Key Factors 1. Fuel demands are low at idle. 2. Wide open throttle at high engine revs uses the most fuel. 3. Fuel pressure must be reduced when manifold vacuum is high. Vacuum pulls fuel out of the injector causing it to deliver too much fuel if the pressure remains high. Manifold vacuum is used to open the pressure regulator at a lower pressure when vacuum is high. A good way to check your fuel pump is to run an amp test on the fuel pump while it is running or while battery voltage is being applied ot it (turning the key on, cranking your vehicle or even when your engine is running. The amount of amps your fuel pump will pull will depend on how much fuel pressure your fuel pump should supply to your fuel rail. A good rule of rule of thumb for this test is as follows: 14 to 15 psi 3 to 4 amps 30 to 45 psi 4 to 7 amps 45 to 50 psi 7 to 8 amps 50 to 70 psi 8 to 12 amps

not sure what your problem actually is. wont start? if you have that pressure at the test port your fuel is pumping fine. need to see if the injectors are pulsing. this is done by removing the easiest injector plug and installing a noid lite. you can get the noid lite at your local parts store. if there is no rapid flashing when trying to crank most likely problem is either the crank sensor or cam sensor. hope this helps

The fuel pump may be about done. Check fuel pressure at the test port in the fuel rail over the injectors (rent the pressure tester)--it should be in the 40 to 50 PSI range with engine idling. If the pump continues to run with the key on, but the engine off, shows that the pump is about worn out. Hope this helps!

If the pressure is slow to rise, you should consider changing the fuel filter if it has not been done in the past 30,000 miles.
Next, disconnect a spark plug and check for spark while engine is cranking. Use a spark tester or old spark plug grounded to the engine block.
Let me know.
Regards,

Just having fuel is not enough on this engine, here are the spec's. Even 1 psi out of spec can cause a no start.

Fuel Pressure
Pressure 1 (PSI) Pressure 2 (PSI) Pressure 3 (PSI) Range Note Range Note Range Note 60.0 - 66.0 Y131 50.0 - 63.0 Y132 66.0 Y133 Y131: System pressure with ignition on (PSI).
Y132: System pressure while idling (PSI).
Y133: Fuel pump pressure (PSI) with return line briefly restricted.

What about the fuel filter????? Have you changed it out??? If you can spary something like a started fluid, that means it is a fuel problem. My last check, it has to be above 50-psi on the fuel pressure to make it run right. I had 35psi, but whould not get over 30mph or down hill maybe 45mph. Check both filter & pressure, but check pressure with a New fule filter!!!!