No engine run at 1/8 tank

[Bitsyncmaster]

I've been doing a lot of engine idle testing software changes on my idle ECU. I had run the tank down to 1/8 tank and this morning I could not keep the engine running after start. I tested a stock ECU and another ECU of mine with the old software and same problem. Added 5 gallons to tank and it ran fine.

So has anyone else seen this problem? It could be my level sender has gone bad and I was out of fuel. Or maybe my Tahoe fuel pump works like that.

I will have to investigate this problem later. I'm to busy working that software now. I wonder how my software testing results have failed because of that fuel problem.

[Timeless]

I have experienced that with low fuel in the tank. OE gauge reading close to 1/4 really equates to my car having VERY low fuel. I fill up when at ~1/4 to not risk running out of fuel. One stop recently I added 11.8-12 gallons with the gauge needle reading just about at 1/4 exactly.
Car has DPI pump setup.

[mhanch]

Stock pump and guage and I can run down to almost empty - but i rarely ever do.

[AugustneverEnds]

I have the OEM spec pump and the DGo sending unit. I regularly run it down until the low fuel warning light illuminates without trouble.

[Helirich]

Mine will run, but runs poorly.

[Citizen]

So has anyone else seen this problem? It could be my level sender has gone bad and I was out of fuel. Or maybe my Tahoe fuel pump works like that.

Two thoughts on this:

1) You might try removing the 5 gallons by siphon into a 5 gallon container (so you know when you?ve removed exactly 5 gallons) and verify the tank gauge is indicating 1/8 full, where it was when you noticed the problem. Then, open the top of the tank and run a clean, straight, metal rod or tube down to the bottom and out again, and observe where the wet mark is (do not pickup a stick off the ground to use for measuring, like believe it or not, I?ve seen some people do?I know you already know not to do that ?.).

You might find, as you indicated, that at 1/8^th tank indication, you were actually out of fuel (or have only a trace left, enough to maybe start and run for a moment until the pump can?t pick up any more fuel). Thus, your indicator is inaccurate.

2) I too have a GM product (though not a Tahoe) that experienced the almost exact same symptoms. I could always start it, but it wouldn?t keep running unless I kept pumping the gas pedal every 10 seconds or so. After verifying fuel level and replacing a number of fuel related parts, and verifying my exhaust wasn?t plugged up (possibly by critters building a nest in there), all to no avail, I finally replaced the fuel pump as a last resort. And you guessed it, it started right up and ran perfectly.

It seems the fuel pump, while not completely dead, was in the process of failing and could not even pump enough to keep the engine idling without pumping the pedal. So after verifying there is more than just a trace of gas in the tank, then verify you have proper, continuous fuel pressure.


My lesson learned: Start with the fuel pump.

Good luck.
Thomas

[Timeless]

Two thoughts on this:

It seems the fuel pump, while not completely dead, was in the process of failing and could not even pump enough to keep the engine idling without pumping the pedal. So after verifying there is more than just a trace of gas in the tank, then verify you have proper, continuous fuel pressure.

My lesson learned: Start with the fuel pump.

Good luck.
Thomas

FWIW my DPI setup is new - installed in August 2022. My fuel gauge reads differently vs. stock setup.

[Bitsyncmaster]

Thanks for all the replies.

I will find out why this happened when I get time to do testing on the pump. What I will do is just put the return hose in an empty tank and power the pump until the flow stops from the return line. It should stop when the pump can not produce 75 PSI since that is what my PPR is calibrated for.

[cis6409]

Mine has oem set up and runs right down to the low warning Light no problem.

Looking at the integrated pump sender pics set up I can't see how it can suck fuel from the baffle location at the back of the tank where the oem one sucks from.
It can only suck from directly underneath itself??

I used to have that same issue when I ran the old Hervey aluminum baffle set up which could only source the fuel from Directly underneath the pump itself..
I had to keep filling up at 1/4 tank otherwise it would splutter or die which got frustrating so I switched back to oem set up and everything was fine again. Back to full capacity and no more range anxiety..

[Bitsyncmaster]

Mine has oem set up and runs right down to the low warning Light no problem.

Looking at the integrated pump sender pics set up I can't see how it can suck fuel from the baffle location at the back of the tank where the oem one sucks from.
It can only suck from directly underneath itself??

I used to have that same issue when I ran the old Hervey aluminum baffle set up which could only source the fuel from Directly underneath the pump itself..
I had to keep filling up at 1/4 tank otherwise it would splutter or die which got frustrating so I switched back to oem set up and everything was fine again. Back to full capacity and no more range anxiety..

That is good thought of why this may happen. Does the tank sit at an angle?