H3T Running out of Fuel with an 1/8th of a Tank Left

[RamRod]

No Fuel Pressure Issue

Hey guys! I just wanted to run this by the forum before ordering parts.

This has happened to my twice this week, but at least the second time I had spare fuel and was on my way with a quick top up.

I am driving up a hill with 1/8th of a tank left on the guage and it cuts out until I either get it to a flat surface or put more fuel in..

Now I know the easy answer is keep the tank full, but what I want to know is what's failing so I can get it fixed since it didn't do this before...

Should I try replacing the fuel level sending unit? Is there a way to recalibrate it?
Or could this be a fuel pump issue?

Thanks for you input!!

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[chaos254]

You can replace just the fuel level sensor but since you have to drop the tank, you might as well replace the fuel pump assembly(comes with a new sensor)

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[ReconH3]

Also check your tank isn't dented. It can cause the sensor to misread or fuel not to get to the pump intake.

 

[RamRod]

Both are good suggestions I will first check for a dent then look at replacing the fuel pump assembly... I am sure dropping the tank is a load of fun!

Thanks!

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[alrock]

Recon's right on target - dented gas tank skids are often the culprit as they bend up the plastic tanks. It's not hard to drop the gas tank skid but if you do you have to bang out the dents or you won't get it back on after the gas tank expands back to its original shape.

 

[alrock]

Here's how Jerry bent his back into shape. I used a BFH on mine.

 

[rascole]

I am driving up a hill with 1/8th of a tank left on the guage and it cuts out until I either get it to a flat surface or put more fuel in.

1/8th of a tank, @ 2 gallons, and it stalls going up hill? The fuel pickup is at about half way back in the tank & don't know how steep the hill is but it doesn't sound like there is anything wrong.

 

[CaseyS]

Total tank volume is 23 gallons. Low fuel light level is right at 20. How much can you top off with from 1/8 level?

 

[RamRod]

I will try this with the next fill since I don't know how much I had in the Jerry Can when I filled it enough to get me to the gas station.

So the tank skid is straight as an arrow! So I guess we can cross that one off the list

 

[alrock]

Total tank volume is 23 gallons. Low fuel light level is right at 20. How much can you top off with from 1/8 level?

FYI, the H3T tank is 27 gallons. Not that the difference really affects this scenario

 

[4speedfunk]

Just because the skid is flat, doesn't mean the tank is. The tank is plastic and it can be collapsed (from pump suction). This can happen on any vehicle if the venting system gets blocked, pinched, or malfunctions.

Way Back...
I had a 70 Nova back in the late 80s. I had accidentally driven away from a gas station without the gas cap. So no big deal...the next day, I swung into CarQuest and bought a replacement cap...popped it on...forgot about it. About ten miles down the road, the car runs out of gas and coasts to the shoulder. I could not get it to restart no matter what. The gauge read 1/2 tank but, I assumed it had quit working and I simply ran out of gas. So I called a buddy and he brought me a fuel can. I went to pour some in, and when I rotated the brand new fuel cap...I heard a metallic BONG, and a long hiss of pressure relieving. I looked underneath and the entire fuel tank was sucked completely flat! That's when I learned that my new cap was not vented, like the original. DOH! I never thought a 230 CID 6 cylinder fuel pump could collapse a steel tank...but it can. The internal float mechanism and sending unit was totally screwed. I never fixed the gauge, but I did use some compressed air and a large suction cup to pull the tank back close to its original shape. I drilled a small hole in the cap, and never had any other issues.

 

[RamRod]

K so stalled out again... I don't hear a fuel pump while sitting with the key in the on position before cranking it... any way to tell if there is fuel pressure?

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[amrg]

If you have a scanner you can pull fuel pressure readings.

 

[RamRod]

Ended up needing to get a tow, while waiting I checked any applicable fuse to make sure one didn't burn out.

I am starting to think some critter chewed a wire, just a couple weeks ago we had to take the wife's car in because a critter ate some wires on a transmission pressure sensor and it would shift any higher then second gear.

While I was checking fuses I found lots of indications that a critter has been in my engine bay, with some poop and pine cone shavings and such.

So I had no choice to get the truck towed to a dealership and have them take a look at it. I had no hope of getting the truck dropped off at home because my driveway is waaaay too steep for the tow truck to get my T up (There are times when I need to put the T in 4hi lock to get all the way up!)

Anyways I hope this dealership figures it out

 

[alrock]

Good luck! Does sound like a critter issue.

 

[RamRod]

Okay dealership says it's the fuel pump, they want $1450 to do the work for parts and labour.... that's bull ****!

I am thinking I will pay them for their diagnostic fee and install a temporary in line pump to get it home (only about 2/3 miles down the road).... now I am wondering is there a good place to temporarily install a in line pump??

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[amrg]

Thats abit steep! I had my fuel tank serviced and it cost me $250. Half the work is getting rid of that leaf spring bolt that otherwise wont allow you to drop the tank.

 

[RamRod]

Thats abit steep! I had my fuel tank serviced and it cost me $250. Half the work is getting rid of that leaf spring bolt that otherwise wont allow you to drop the tank.

The one lucky thing here for me is I cut that bolt out (picked up a replacement) and installed it the other direction years ago for that very same reason!

It will be a breeze to drop I just need a place to do it...

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[RamRod]

Update- ordered pump assembly from Rock Auto and paid for express shipping... when it gets here I found a shop that will install it for $300.... now I just need to tow it there.

It was very hard to find a shop that will install customer supplied parts... they are learning how to make money that's forsure!

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[4speedfunk]

Delco pump I hope.


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[RamRod]

Yes, OEM replacement...

Man it's hard getting the siphon in the bottom half of the tank, I think the line curls up on me so I have been getting a lot of air on the last part of draining the tank


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[RamRod]

So I got the fuel pump replace this evning, took me about 3 hours from start to finish... but I don't get to go for a drive to tell if that fixes my issue or not.... bent a hard brake line and now its got a slow leak... so have to replace that before going for a test drive and confirm that this was the issue or not

 

[RamRod]

Okay update:
New fuel pump has been installed... As I installed it I broke a hard brake line.
A new hard brake line has been installed to fix the broken one.

Took the truck for a test drive, it all worked just fine.

Parked on a slope.... It won't start again.

I looked at all the fuses and looked for any broken wires and everything looks like it should.

I went and replaced the factory battery terminal connectors.

Still nothing.

I am at a loss! Does anyone have any other suggestions???


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[Kyle]

Okay update:
New fuel pump has been installed... As I installed it I broke a hard brake line.
A new hard brake line has been installed to fix the broken one.

Took the truck for a test drive, it all worked just fine.

Parked on a slope.... It won't start again.

I looked at all the fuses and looked for any broken wires and everything looks like it should.

I went and replaced the factory battery terminal connectors.

Still nothing.

I am at a loss! Does anyone have any other suggestions???


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have you tried rolling it to a flat surface and trying again to start it? how much fuel is in the tank?

 

[RamRod]

Tank is full, I have it basically stuck in my driveway and can't get it to a flat surface without getting a tow... so I haven't been able to test that out yet..

I read on a few other non Hummer forum's that people with the same issue as me replaced the Fuel Pump Drive Module with good success... so I ordered a replacement a little while ago....

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