Stalling with gas tank below 1/4

This has been happening for a good 6 months or more. If the gas tank is below 1/4 it won't start. Once fuel is put in, it's fine. It doesn't skip or run rough. Lately, I've been stalling while driving. Not from a standstill. No warning, just dies for no reason. Plenty of gas in the tank, at least 10 gallons when this happens.

Obviously, I'm hoping someone says "clogged screen on fuel pump" but fearful someone is going to say "fuel pump"

I also have the lights flickering. Alt shows fluctuation, breaking will dim them for a moment. Is this the alternator or a wire come loose maybe?

Thanks for your responses.

2002 Suburban 1/2 ton
150K miles
5.3 engine

Check the fuel pressure. If you regularly run it below 1/4 tank, it probably is the fuel pump. The fuel cools the pump, making it last longer.

Check to make sure there are no loose wires, if not, check the alternator output. Also check the battery. A VERY weak battery can cause the voltage to fluctuate too.

It is possible that the voltage droping too low could cause something to quit, making the engine stall. Does it re-start when it dies?

It will restart after I add a gallon or two, usually needs two.

this problem is becoming more common as gas prices rise many vehicle owners are not maintaining at least 1/2 tank of gas. as mentioned this causes pump overheating. also because gas now contains alcohol more moisture reacts with the fuel creating contaminates the plug up the fuel delivery system.............

Alcohol does not contibute to " plugging" the fuel system, only dirt or fuel born contimantes can do that., 5-10% mix can contribute to holding some moisture if the vehicle sits for long periods of time.

Here's a thought... Your guage is off, making you think you have 10 gallons left when it's sucking air.

It's a nice thought, but I have a 32 gal tank and USUALLY keep it above 1/4 and end up putting in like 18-20 gallons at a time. I think I'm going to keep it closer to 1/2 and above now. Damn fuel pumps are expensive.

i would guess the stalling is the crankshaft position sensor.as the 5.3's have a problem with this.

I'm a very big n00b when it comes to this question I;m going to ask. We have one of those computer code readers. Is this something that would tell me if this sensor you are talking about is going or gone? To be shamefully honest, I haven't even taken it out yet.

yes it will read all the codes that the pcm has stored. and most of them have a code book with the scanner to tell you what the codes are for. j-ri also has a point about the gauge reading 1/4 and it quitting. could be that the sending unit which is made on the fuelpump is off leting it be out of gas with 1/4 still showing

Well, a little update and unfortunately, still the same is going on. I had the fuel filter replaced. The garage took it for a drive and didn't notice anything out of the ordinary. He put it on the computer...nothing.

I asked them to test the fuel pump pressure and these are the results.

This is what the paperwork says exactly.

pressure is testing at 50 psi on and 42 psi running.
should be 56-65 on and 45-59 idling.

They said while it is out of range, it still may be good enough that it isn't what is causing my problem. They don't know for sure.

If I step on the gas hard, it sputters. If I'm going up a hill, that's when she stalls. Usually doesn't happen until I've driven an hour, but by then, I'm pretty far from home. It usually doesn't happen when I'm leaving my house first thing. Occasionally it has not started instantly, but then it starts after the first try.

One last item. When I do stall, it doesn't shut down completely. I leave it in drive, pull over to the side, and by the time I stop, it's still running slightly, then dies. If I wait 5-10 minutes, it'll start right back up, though with the same sluggish acceleration as before.

My guess would still be the fuel pump. At 500+ I would like the garage to make sure that's what it is rather than "well, lets try this.....nope, that'll be 500+ and whatever else is wrong with it"

I have been running my truck with at least 3/4 tank full just to make sure. I only put about 8 gallons in and have been doing that for a week now.

I hate that. Thank you guys for your responses. I appreciate the help.

with the vehicle running is the voltage at fuel pump 12.5volts ? if less find out why.......if 12.5volts or more pump n/g. your problem 1/4tank and will not run is fuel pump/tank screen pickup problem so the tank is coming out as this will get worse with time.......

Not to sound like a weisenheimer, but why not keep it at 3/4 full or more?

framerman, the cranksensor will not always pop a code if it is only slightly cracked as mine was .it would just die mostly on a rough road but sometimes on a smooth road at any speed. i had it checked for codes ,no codes came up. my fuel pump just decided to act up at the same time it would only pump two pounds pressure . so put a $420.00 pump in . two days later quit in the middle of a road like i had cut the key off .i have an '02 with an 8.1 vortec and i take it you have a 5.3 which has twice the cranksensor failure as 8.1. the cranksensors cost anywhere from $90 + at dealer or as low as $63.00 at autozone. i went with the dealer one as he had it on the self and everyone else had to order it. the pressures on your pump are good if they do not drop out as i have seen some g.m. pumps do. by this i mean it will hold 40+ then
then for a moment drop down to 10lbs then slowly build back up. to check for this you have to let the pump run up to 30 minutes and if it holds for 30 minutes without dropping below 42 lbs then it is not your fuelpump. another thought is that your sending arm is bent or hanging at 1/4 and it is on the side of the fuelpump in the tank. as the f/pump is made as a whole unit. how many miles does your truck/suv have on it?

if the pick up in tank is out of position and pump runs dry he will most certainly need new pump very soon....

I like my new garage guy. He did everything I asked for him to check, the sensors, the electrical, the filter in front of the pump, etc. I actually got a sense that he was being genuine. I still have to pay for a pump though. He said he eliminated all he could and it still came back to the pump.

As a side note, the previous time I took my vehicle to him, this guy noticed I was running on my spare which is not a donut tire, but a decent spare that you can run on just like regulars, but it didn't match. He actually had a match out back, a decent replacement that matched my other 3. Same tires, lots of tread left on it.

He mounted it, balanced it, stuck it on my truck, sent my spare back underneath all at no charge. Nice and warm fuzzy feeling. I think I have found my auto mechanic.

the g.m. fuelpumps i have seen on my '99 van and a '02 silverado both have the pickup hole at the bottom with the filter on the bottom . the filter sits right on the bottom of the tank . the pump has springs that you must compress as you push the pump down in the tank to lock it in position.

As far as your stalling problem with low fuel tank, I just got done with fixing the same issue after living with it for 6 months. I was told over and over (not on this forum )that fuel pumps either work or they dont work, they dont fail intermittently. When mine was well below a quarter, it would consistently stall around curves and dead stop acceleration. I replaced the fuel pump myself ($225 i think) and no problems since. Not a difficult job, just unwieldy as in the size of the tank. The only real difficulty I had was getting those dam fuel line connectors off at the tank. They are a real PITA.

BTW, from what I have heard, 150k is well over the expected life of a fuel pump, especially if you drive if frequently below half a tank.

yes these pumps will sometimes refuse to die and will pump then not pump. mine would die or jump , buck and backfire then next minute it would run 90 mph as long as you would hold it down. and about the only way to be sure the pump is doing this is to pressure test it. i actually took the fuel filter out and put a pressure gauge in and that was how i found out my pump wasn't pumping and holding pressure .mine would only be pumping arond 5-10 pounds pressure when it would either die or buck. these are not the best made fuel pumps but they sure are proud of them when you go to buy one.

Below-spec fuel pumps are VERY common.... probably even more common than one quitting altogether. Checking for fuel volume is as, if not more, important than pressure. A pump can suppy 58PSI at idle, but as soon as demand increases it can drop to almost nothing. And anything can be intermittent, especially electrical stuff.

Framerman, we are having the EXACT same problems as you on our '03 Suburban...please tell me if replacing the fuel filter did the trick before I spend all the money to replace it!!! Thanks!!!!

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buy a fuel pressure gauge check pressure at fuel rail when veh stalls stop guessing it would drive me nuts not knowing if i will make it home. if pump proves bad change if pressure proves pump good then you have some direction

please tell me if replacing the fuel filter did the trick before I spend all the money to replace the fuel pump!!!

No one can guess this; but if it's been a few years since the fuel filter was replaced, it's worth a try. I just replaced my fuel filter last week on my '94 Sub, figured it had been a few years and I'd just had a new fuel pump installed and didn't want higher than spec back pressure. It was $15 Fram G3727 if memory serves at CSK/O'Reillys. It's located on the frame rail , look underneath across from driver's door. The fitting takes a 16mm flare wrench and the filter takes 20mm open end wrench. The plastic mount is ill-designed and must be shoved to the side, biggest pain of all. You'll get some gasoline spilled, wear eye protection.