Drove with 1.5-2 gallons of gas, did I hurt the fuel pump?

[Benny B]

Cheers Everyone! I am a longtime owner of a 1995 GMC Seirra Extended Cab 2wd 350 5 Speed. I love the truck, I pull my trailers with it and the truck supports all of my racing adventures. No AC, No Radio, No Problem! I am very lucky to find this forum, I am now just finding out about the finicky fuel pumps these things have and all the work needed to swap out a fuel pump.
Last week I was trying to get home by a certain time and I was wanting to burn out all the "Summer Time" gas in the tank (I store it all winter with a full tank of Rec Gas). I got it home with only about 1.5 to 2 gallons in the tank. I was pretty far below the E mark on the gauge, I should have stopped at a gas station. The truck was running fine, I filled it up the next day with Rec gas, 23 gallons. I don't normally run it down to Empty. Well when I did a warm/hot start it cranked MUCH longer than normal before finally slowly firing up. I am going to change my fuel filter, I might have picked up some garbage in the tank running it that low. Plus, I have never changed the fuel filter, so its due for sure.
Do you guys think I could have ruined my fuel pump by doing this? Cold starts are great, its the warm/hot start that started acting strange. I feel like one time should not have killed it, but I don't know how old that fuel pump is, the truck has 225,000 on it and I have owned it for 20 years. I think I got it with 180,000 on it. I hate self inflicted wounds.
Thanks for the help, I am looking forward to hanging out on this forum.

Ben

 

[alpinecrick]

Running low on gas and hurting the FP is a myth. What burns up fuel pumps is not changing the fuel filter every 15k. Not 20k, not 30k, but 15k.

Blow through your new filter. Now remove your old filter, blow out the gas and blow through it again. Feel the resistance? That’s what kills fuel pumps. More resistance, the less lifespan the current pump will have…..

AC Delco or Delphi.
Although allegedly the Bosch pumps have improved, originally they were a POS.

 

[Komet]

Fuel pumps either work or they don't. If yours is still working, it's fine. Do change the filter though.

 

[alpinecrick]

Fuel pumps either work or they don't. If yours is still working, it's fine. Do change the filter though.

Sigh......
I could spend the rest of the night telling the stories how I learned the hard way about fuel filters on GMT400's. Haved owned a 91 5.7 that I put 275k on, and currently own 4 Vortecs 5.7's/5.0 that I have put approximately 400k+ on.

The parts manager at the Chevy dealership (the original owner of my 97 K1500) told me this over 20 years ago: When a truck came in with a plugged or partially plugged fuel filter they would recommend replacing the fuel pump. If the customer chose not to have the pump replaced the service manager would make sure to note on the invoice that a fuel pump is recommeded within the year. The service manager learned the hard way if they didn't do that and the customer's fuel pump quit the customer often blamed the dealership for the fuel pump failure because they were the ones who changed the filter.

My 97 K1500 has ~168k on it and still has the original fuel pump--because the original owner and I changed the fuel filter every 15k. Ok, I might've gone 16k or even 17k a couple times......

The fuel filters on these GMT400's have a ridiculously small pore size. Just a few microns or something like that. Smaller than any other auto fuel filter I've heard of.

 

[Schurkey]

Fuel pumps either work or they don't. If yours is still working, it's fine.

Not at all true. Fuel pumps are often "wounded"; still pumping but at reduced maximum pressure and/or volume. A TBI pump should be able to output 15+ psi dead-headed, even if the regulated pressure is spec'd at 9--13. Any number of pumps have a burnt bar on the armature, or worn pump mechanism so that max pressure is only 9 or 10 psi--still within spec until the engine fuel demand goes up.

Do change the filter though.

Good idea.

It takes ONE tank of contaminated fuel to potentially plug a fuel filter. For that matter, you may have plugged the filter sock on the inlet to the pump.

TEST FUEL PRESSURE and make sure that you verify pressure under high-demand conditions. Most fuel pressure testers have a release button on the side, connected to ten feet of crappy clear-vinyl tubing that becomes yellowed and brittle. Push the button, flow fuel into a drain pan, and make sure the pressure doesn't drop.

 

[351FUN]

I might have picked up some garbage in the tank running it that low. Plus, I have never changed the fuel filter, so its due for sure.

How do you think you picked up garbage? The pump pulls from the bottom already, it's always gettting the stuff down low. Having less in there doesn't matter because it's pulling from the bottom already. Definitely change the fuel filter though if you haven't done it before, I change them yearly at least.

 

[Benny B]

I have also thought about the fact that the sock is at the bottom of the tank so it really shouldn't matter what the fuel level is, you are going to be pulling from the bottom of the tank, but I guess maybe in extremely low tank situations you pick crud up? I don't know, I've always been told that but it never made 100% sense to me.

 

[Benny B]

Update: I replaced the fuel filter but t I still have the long crank when engine is warm problem. I didn't notice this before running it so low on gas, but I generally only drive it for 90 minutes then shut it down for 6 hours, so it's POSSIBLE I have had this problem for a while. I probably messed something up by letting the gas get so low. Should I check anything else before jumping into the fuel pump? Do I really have to take the bed off to do the fuel pump? I'd rather drop the tank. Thanks, Ben

 

[Schurkey]

Update: I replaced the fuel filter

Good.

but t I still have the long crank when engine is warm problem. I didn't notice this before running it so low on gas, but I generally only drive it for 90 minutes then shut it down for 6 hours, so it's POSSIBLE I have had this problem for a while.

Verify fuel pressure. Assure the fuel system primes when you turn the key from "Off" to "Run".

Connect a scan tool, look for "codes" but also verify EVERY sensor and computer output.

How old are the usual "tune-up" items: Distributor cap and rotor, plug wires, spark plugs, air filter, initial ignition timing checked, EGR checked, etc.?

I probably messed something up by letting the gas get so low. Should I check anything else before jumping into the fuel pump?

Verify fuel pressure, verify proper electrical power to the fuel pump by checking voltage AS CLOSE TO THE PUMP AS PRACTICAL, with the pump RUNNING. Assure there's no voltage on the fuel pump ground wire.

Do I really have to take the bed off to do the fuel pump? I'd rather drop the tank.

I've done it both ways. Both ways suck. No matter which way you do it, you'll likely run into rusted fasteners.

MOST folks would rather lift the bed than drop the tank. Your choice.

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[someotherguy]

It may help to understand how the tank is designed - on the TBI stuff and early Vortec there's a tray stuck to the tank bottom, acts as a sump so that there's always fuel surrounding the pump inlet (sock) even when the level gets low. About mid-1997 on the pickups they did away with this and went with a canister style pump/sender combo that is self-contained and the canister acts as the sump.

Like Schurkey is telling you, check the pressure. This is critical information when troubleshooting the fuel system.

A somewhat common issue with a submerged pump like this on the TBI trucks (and again, the early Vortecs) there's a short section of rubber fuel line joining the pump to the hard line on the sending unit. After many years of fuel exposure, this hose gets eaten up and cracked or pinholed. One of the symptoms I've seen this cause is.. wait for it.. longer crank times. Eventually they can get bad enough the pump cannot build sufficient pressure in the system because it's just coming out of the holes in that hose.

Richard