Help w/ sick '94

[nate]

So I got a '94 GMC Sierra SLE - XCSB about a month ago with ~119K on it. I've only filled it up twice. I wanted to see what kind of MPG I'm getting before I do some tune-up/maintenance on it so I was planning on running a full tank through it. Well, yesterday I ran out of gas...for two reasons 1) the gauge isn't accurate I learned; it was just entering the orange, and 2) I was thinking I had a 32 gal tank (my mistake). Anyway, I got some gas in it started it up drove 2 miles filled it up. Drove 1.5 miles home and parked it w/out issue. This morning it won't start. It turns over and over by no hint of gas igniting. It doesn't seem that it running rich (don't think it's flooding) or anything, but I haven't been able to dive into it w/ work and getting ready to hunt tomorrow. I am just wonder if any of you have ideas/first things to look at? Thanks in advance.

 

[GreaseDog]

you ran the tank dry of fuel. my guess would be a bad fuel pump. without tearing into it, and doing some diagnosing yourself, nobody here is going to have a magical answer, only suggestions as to where the problem may be.

 

[nate]

you ran the tank dry of fuel. my guess would be a bad fuel pump. without tearing into it, and doing some diagnosing yourself, nobody here is going to have a magical answer, only suggestions as to where the problem may be.

Thanks...that thought crossed my mind...but would running the tank dry do that to a pump? The pump got me to the gas station and then home? Thanks.

 

[SAATR]

Thanks...that thought crossed my mind...but would running the tank dry do that to a pump? The pump got me to the gas station and then home? Thanks.

Yes, most definitely. When you run the fuel tank dry on a pump-in-tank vehicle, your fuel pump no longer has any coolant or lubricant, as the fuel acts as both. What happens to any internal combustion engine that is run hot and without oil? Severe bearing damage or complete lockup, IF you are lucky. The same applies to fuel pumps whose journal or needle bearings will quickly fail, and seize, without proper lube. It may be that when your pump cooled down completely, the clearances tightened up on an already damaged bearing and the pump no longer has sufficient current (translation: torque) to start spinning again, as any electric motor has its peak current draw when starting up.

But this is all hypothetical, and without a fuel pressure test to confirm a failed pump it will remain so. Do as greasedog said and test a few things to see what's happening with your truck, specifically fuel and spark.

 

[nate]

Well....it's been busy, but I had a chance to check and there's no fuel coming out of the injectors. I double checked the fuse, although I doubted it was the cause, and it's o.k. So there's a real good chance the pumps shot. Thanks SAATR for the education...I learned something. So as far as I can tell this is a top mounted pump...not easy to get out...right? Who's done it before?

 

[bizzo15]

Easiest way is to undo the bed bolts and unhook any grounds and wiring and slide the bed back a few feet and access the pump that way. If the truck is a real beater and you just don't care you could cut a whole in the bed directly above the fuel pump and access that way.

 

[GreaseDog]

Well....it's been busy, but I had a chance to check and there's no fuel coming out of the injectors. I double checked the fuse, although I doubted it was the cause, and it's o.k. So there's a real good chance the pumps shot. Thanks SAATR for the education...I learned something. So as far as I can tell this is a top mounted pump...not easy to get out...right? Who's done it before?

crack the lines at the back of the fuel filter, and turn the key on. if you have nothing there, pull the bed. i've got 3 4x4s, 2 are the width of the bed, and the other is 6 1/2 feet long, with an eye bolt in the middle. bolt them together in an "H", hook the cherry picker on, and the bed is off in less than 10 minutes with no breaking your back. make sure you have good power going to it, as well as a good ground. there is a connector you should be able to get to from inside the frame by the tank to test for power.

if you have fuel at the filter, crack the lines at the TB. if you have fuel there, i would start looking at the ignition system... that is what triggers the injectors to fire.