Low Fuel Light/won't Start

Zimm · September 2, 2009

My '05 2500 6.0 4x4 gas truck wouldn't start tonight for the first time since I've owned it. It has 59K miles and I don't let the fuel get below 1/4 of a tank. The low fuel light is on and the gauge is just below "E", but the tank is full.

I've read about the dreaded tank drop or bed removal for fuel pump/sensor access, but thought I'd get some input from you guys first. Would the sensor stop the pump from working (or vice versa)? I tried a different relay for the fuel pump and the fuse is good. I believe I hear the pump click when I roll the key, but I'm not positive. Any ideas?

Thanks,

Zimm

rodram · September 2, 2009

if you are suspecting fuel delivery issues, then have your fuel pressure checked ... before ripping any parts out it would be good to know the fuel pressure.... I don't konw what the spec pressure range for a '05 6.0L is but someone should be able to say... or a parts ahop guy should know

Haulin' 8.1 · September 2, 2009

The relay clicks, the pump would whine or whir. You may have to listen under the tank or at the filler tube with the cap off while someone else cycles the key off/on. The sender doesn't effect the pump but they share the same ground so it's likely there's a bad connection or poor ground. The ground is on the frame below the drivers feet area, rear side of body mounting ear. Clean and tighten. If you're going to do it yourself and the tank is full it would be easyer to raise the bed over the tank. You can just raise one side proped up like a piano and leave the other side bolts in really loose. The pump connectors themselfs are very problematic and new pumps usually come with a new design that will need to be attached to the truck harness to connect the new pump.

Vernon

Kodiak450 · September 2, 2009

Thats sucks! Having a full tank and needing a new pump. Thats a 34 gallon tank too! I would venture to say your pump needs replacing, but would bring it down to an automotive shop so they can verify it. It could be you can hear it whine, but something else is going on inside tank. The fuel guage that monitors the levels of fuel is inside tank and part of the fuel pump. I'm hoping my fuel pump goes within the next 2-3 years, this way I get a new one for free! Good luck and let us know how you made out.

Zimm · September 2, 2009

Thanks for the replies. I'm going to spend some time searching for a ground or connection issue before tearing into things.

Thats sucks! Having a full tank and needing a new pump. Thats a 34 gallon tank too! I would venture to say your pump needs replacing, but would bring it down to an automotive shop so they can verify it. It could be you can hear it whine, but something else is going on inside tank. The fuel guage that monitors the levels of fuel is inside tank and part of the fuel pump. I'm hoping my fuel pump goes within the next 2-3 years, this way I get a new one for free! Good luck and let us know how you made out.

Zimm · September 2, 2009

Well, I cleaned the ground wire, but it didn't help. I had a friend turn the key for me and the pump does run for about a second, then stops. It does this every time the key is turned and the pump motor sounds normal. There is no fuel/fuel pressure at the Schrader valve on the fuel rails.

Could there be a faulty sensor that is telling the pump not to run? I'm working on getting the codes read. There is an amber engine icon symbol which has been on for some time. According to the manual, it's an emisssions issue. It never affected the way the truck ran or started.

Thanks for the replies. I'm going to spend some time searching for a ground or connection issue before tearing into things.

Thats sucks! Having a full tank and needing a new pump. Thats a 34 gallon tank too! I would venture to say your pump needs replacing, but would bring it down to an automotive shop so they can verify it. It could be you can hear it whine, but something else is going on inside tank. The fuel guage that monitors the levels of fuel is inside tank and part of the fuel pump. I'm hoping my fuel pump goes within the next 2-3 years, this way I get a new one for free! Good luck and let us know how you made out.

Kodiak450 · September 2, 2009

How's your fuel delivery line look? Filter been changed often? I replaced my fuel line a few months back. Had to order it, cause GM has a patent on the damn thing, repair shop told me it would of cost me $320 for it, I got it for less at gmpartsselect.com or some site like that.

tramz · September 2, 2009

Just a thought, have you disconnected the your battery cables?

Zimm · September 3, 2009

The truck was running perfectly when I shut it off the last time. I suppose something strange could have plugged the fuel filter suddenly. I'll check into that. I disconnected the batteries for half an hour, then reconnected them last night to see if it would "reset" something, but it didn't help. Thanks again for the ideas though.

Just a thought, have you disconnected the your battery cables?

Zimm · September 4, 2009

Problem found and fixed! All seven wires leading to both plugs on the fuel pump/sensor were CUT OFF or chewed(?) off within 1/4" of the plugs! The noise I thought was the pump motor was something else because there was nothing connected to the pump at all! I live in the country back a 500' lane, so someone could have snuck up during the night and cut them.

There are lots of squirrels that have found their way into everything out here (including my firewall insulation), but I can't feature them getting those wires so precisely. On the other hand, if someone cut them, it was a very specific, well-informed form of vandalism. I checked everything else I could think of, including the brake lines, then took a test drive. All seems well.

Kodiak450 · September 4, 2009

Those wires, aren't they above the gas tank and hard to reach? Could be mice because mice are also known for cheowing wires as well as rats.

If I were you, i would get some trapper T-Rex mouse traps and either use a lure bait or bait them with peanut butter and place a couple under the parked truck at night. Mice and rats are attracted to wires, and will knaw on them because the'r teeth are constantly growing and need to file them down and are known to chew on wires. If you have rats running around, i would make a habit of checking brake lines daily as they are known to chew on them.

Zimm · September 4, 2009

I'm leaning more towards the rodent idea also. We don't get rats out here, but field mice, chipmunks, and squirrels are everywhere. I do set out bait and traps for the mice, but now I'm setting a live trap beside the truck! Since telling my coworkers about this, I've heard many stories of chewed wires. Like you said, those wires are very tough to reach at all, let alone cut them.

Thanks again for everyone's replies. It's nice to go into the weekend with the truck FIXED rather than spending three days of working on it.

Zimm

Those wires, aren't they above the gas tank and hard to reach? Could be mice because mice are also known for cheowing wires as well as rats.
If I were you, i would get some trapper T-Rex mouse traps and either use a lure bait or bait them with peanut butter and place a couple under the parked truck at night. Mice and rats are attracted to wires, and will knaw on them because the'r teeth are constantly growing and need to file them down and are known to chew on wires. If you have rats running around, i would make a habit of checking brake lines daily as they are known to chew on them.