2000 5.3 Suburban starts then dies

I looked around for similar issues before starting this thread, lots out there that's close but I haven't seen what's happening to my 2000 Suburban.

I don't see a connection but it's good to know recent history. In the last month two things have happened - battery died (wouldn't start on Christmas eve and wouldn't stay running after jumped) and my fuel pressure regulator was leaking about a week after giving me hard-starting. Both are resolved.

Anyway, today I took the family to the zoo. 4 hrs later it started but stuttered then ran fine. Got about 4 miles and it wouldn't take any throttle, stuttered then died. It restarts but stumbles, won't take any throttle and dies within about 15 seconds. Tough to really test with interstate traffic but I don't hear my normal fuel pump whine so that's what I'm guessing. I'll get fuel pressure readings tomorrow, after I get a tester. I'll check the fuse and fuel pump relay also but I don't think I'll be that lucky. It's just weird that it would run at all.

I did notice that no fuel comes out of the rail with it off, but does when the key is at run. Maybe leak down?

Here's the update:

According to the fuel pressure tester there was 10 lbs on the rail. I installed a new pump and now there's 50 psi. Based on what I've seen that means there's still a leak and since the pressure regulator is new it's likely on the return side.

Just a note to anyone that undertakes putting in a new pump - do whatever you have to to get all the gas out first. Also the dealerships were closed yesterday so I bought a Carter, from the other info I have read it sounds like this is going to happen again....ughh

I'll see if I can pinch off the return line tonight and see what the tester tells me.

be careful on pinching the return line. leakdown occurs on all vehicles, but there is a spec for it.....something like not to leak down more than 10-15psi in 3-5 minutes after key is set to off. might be worth looking up. did you also change fuel filter at pump change?

latest update:
Pressure with key on/pump on: 57
Pressure with key on/pump off: 54-55
Pressure while running: 49
Pressure with vacuum to pressure regulator removed: 57
I have not been able to do the pressure warmed up under load, nor do I plan to anytime soon.
Leak down is ~2 psi/min. I don't have it in front of me but I think the book says it should be 1 psi/min.

On the question of if I have replaced the fuel filter the answer is yes. I did that before replacing the pressure regulator ~ 2 weeks ago when I was having some hard-starting conditions.

From what I've read pressure really becomes important for cold starts. I'm in MN and it's 0 degrees F now dropping to -10 tonight. I figure that should be a good test. If it starts and runs well I think I will just accept that this non-OEM pump will not deliver the rated pressure until it fails.

Another bummer is the fuel-level sending unit must be off as it gave me the low fuel light but only took 18.7 gal on a 26 gal tank. At -10 I won't be signing up to adjust it anytime soon.

it may be that you have a small amount of water in the fuel, causing these problems. i assume it only happens in very cold weather? if so, get some fuel treatment for that kind of weather, maybe someone can reccomend a brand as it isn't really needed in south texas.

[quote=chevychev]latest update:
Pressure with key on/pump on: 57
Pressure with key on/pump off: 54-55
Pressure while running: 49
Pressure with vacuum to pressure regulator removed: 57
I have not been able to do the pressure warmed up under load, nor do I plan to anytime soon.
Leak down is ~2 psi/min. I don't have it in front of me but I think the book says it should be 1 psi/min.

these readings look good from the 2000 gm manual i have the fuel supply pressures are ample. remember that the guages can be off so if your close it is ok 10%. because the regulator was bad i would be concerned that the cat may have been damaged by excessive fuel to engine.