Bad gas, siphoned tank, now wont turn over.

[wes335]

The truck is a '94 Explorer 4x4. About a week ago I filled it up with about 16 gallons of ethanol free gas. I drove it home (3 miles) and it was parked for about a week without being cranked. When I tried to crank it for the first time since driving it home from buying the gas, it ran horribly, would sputter out when idling, would bog down when trying to rev the rpm's past 2k, and was missing on cylinders. But it consistently would turn on, even though it ran awfully. There was no smoking coming out of the exhaust, but it smelled sorta like charcoal lighter fluid almost. I figured the gas was bad or had water in it, so I siphoned 18 gallons out of the tank and filled it up with 2 gallons of gas from a different gas station. Now the truck wont start at all. It turns over fine, but will not fire up. Did my fuel pump just die? or what is going on with the truck? Any help would be appreciated.

 

[wes335]

Before I drained all the gas, I remember hearing the fuel pump humming when the truck stalled out. Now when I go to start the truck, I no longer hear the fuel pump humming. What are the chances that the gas I siphoned out is fine and its all just the fuel pump? The fuel pump was replaced a few years ago. I checked the inertia switch and it seems fine. What do I check next? Relay?

 

[Anime]

You should hear the fuel pump engage to prime the system when turning the key to the first position. If not, something is wrong and the reason it will crank but won't start is it's not getting fuel.

Check the fuel pump relay under the hood first. Swap it with the A/C relay (with the A/C off, of course) and see if that makes any difference. If so, old/bad stuck relay. Common issue.

If swapping relays or even trying another one doesn't do anything, you'll likely have to trace the electrical issue, find out why the fuel pump isn't turning on. Could be a shorted wire that's been rubbing and finally grounded out or could even just be a cheap fuel pump that finally went.

The ECM (engine computer) can also develop problems, the capacitors on them leak over time and damage the board and CPU. If you can't find any other solution, pulling the ECM and checking the board for evidence of leaks can be the issue when nothing else seems to be wrong. This usually manifiests itself as a fuel pump that only comes on in warm temps or that stays on whenever the key is on, rather than one that won't turn on, but it varies somewhat depending on the leak and what circuits are damaged.
Just something to check when nothing else seems to be wrong.

 

[Roadrunner777]

Ditto the relay advice. If fact, it would be quite reasonable to buy a spare and throw it in the glove box. A ten dollar part beats a fifty dollar tow charge.

 

[wes335]

Sorry for the delay. Working on the truck has been on the back burner for awhile. I tested the relay and tested OK. Also the truck is getting spark. Still no sound coming from the fuel pump. Checked the plug at the behind the fuel tank and it gets 12v to the red wire when the key is turned to the on position. So basically I have concluded that the pump is dead? Is there something that caused the pump to die within a few years with less than 1k miles on it? How much of a pain is it to drop the tank?

 

[awood]

There are threads here that describe cutting an access hole in the floorboard so you don't have to drop the tank. I've never done it, but will if I ever need to.

An easy check to confirm a problem before a lot of work...use the free tool loan service from your local auto parts store and get a fuel pressure gauge. Confirm that you have no fuel pressure at the fuel rail before going after the pump. But I agree - if your pump isn't priming, it isn't working.