Am I Askin' for Trouble?

[Inbred Redneck]

Haven't been able to figure out how big my tank is so I've been thinkin' about just runnin' her out of gas (while carrying a can with about 1-1/2 gallons) then seein' how much it takes to fill the tank and can. Great way to figure out MGP, too.
Possible drawbacks are suckin' crud into the fuel line/pluggin' screen in tank, lettin' in-tank pump get hot from havin' little gas to help cool it (AFAIK it's the original pump) and goin' through the whole thing of re-establishing prime in the system.
Is it worth all this, just to know the tank's capacity, thereby having a baseline for guessing total range, given approximate known MPG?
It's an '87 STX, 2.9 4X4 with 5-speed and 3.73 gears, or that's what the thing was when it came from the factory. To the best of my knowledge, there've been no mods in the 145K miles on it.
BTW, the trip odometer right now is showin' about 220 miles since last fill up.
Tell me what's wrong with this plan.

 

[RonD]

It is a 17 gallon tank in all '87s, short bed, long bed, extra cab, all 17gal

Running tank dry won't "suck anything in", fuel pump is always at the bottom of the tank so only sucks stuff in from the bottom.

Yes, the fluid in the tank does cool the low pressure pump in the tank, but what cools the frame rail high pressure pump.............yup not a thing, so no you won't hurt pump running it dry.

After running out of gas, hope it isn't in a busy intersection , because it will just die, not slowly sputter, engine will just be running then not running.

After adding the gas, turn key on count to 3 then turn key off, repeat this 4 times, then crank engine.
If it doesn't start then repeat the key on, wait, key off.
Each time your turn the key on computer will turn on pumps for 2 seconds, and 2 seconds only, so off and on, wait, off and on wait

 

[adsm08]

Ron, my book disagrees with you. So does my math. Even when I pull up to the pump I have never gotten more than 14.5 gallons in my tank.

Also, I have this book here that says Midship tanks SWB 15.2, LWB 17, supercab 14.5, and aft-of axle is always 13.

 

[Inbred Redneck]

Hey, thanks RonD and bdsm08 for the quick comebacks. If the 13 gal. is correct and I'm gettin' my average of 17mpg, that means I'm about due to run out when I go out and start the truck tomorrow morning. ;^) Anything more than that is gravy. Since it's the supercab, 14.2 gal. gives me another 20 miles.
The gauge still reads a rch above empty so I should be able to make another round trip or 2 to work. Man, just think, though, of 17 gal. and a range of
almost 290 miles. That'd get me from here past the Oregon border, where gas is cheaper. Then again, I can't pump my own gas there so I couldn't burp the tank to get in that extra 3 quarts.
I'm prepared, by the way, if I run out in an intersection. Done bypassed the malfunctioning clutch safety switch, so I can put her in 1st and crawl over to the curb on the starter motor.
Oh, yeah, for you youngsters, if you don't know what an rch is, as a unit of measurement, go ask the oldest mechanic you can find.

 

[adsm08]

The 13 gallon tank is the auxiliary aft-of-axle tank that was found in about 2% of all Rangers 83 to 88. You have a 14.5 gallon tank.

 

[Inbred Redneck]

Thanks again, gentleman. That 14.5 is close enough. Still only gives me about half the range of my '90 Festiva but the Ranger will haul a little more.

 

[ab_slack]

After running out of gas, hope it isn't in a busy intersection , because it will just die, not slowly sputter, engine will just be running then not running.

I don't know about this. Most other vehicles I have had gave one or two coughs and were dead but in my BIIs with 2.9L always gave me lots of warning if I paid attention. Earliest symptom being very similar to a fuel filter getting clogged, it stutters a bit under acceleration. And it just progresses worse and worse. I've been able to eek out as much as 15 miles from first hints engine gave me. Obviously it wasn't really out of gas at first signs. I found best way to eek out miles was drop it in lower gear and light touch on gas for hill climbs and acceleration and higher gear with light touch for downhill, or neutral.

 

[Inbred Redneck]

'Til I got my Festivas 7 or 8 years ago, I hadn't had any vehicles with FI. With carbed vehicles there was always plenty of warning when gas was getting low.
My old '65 F100 had an intermittent fuel problem where it'd run great for days, then would all of a sudden get starved for gas. I'd change fuel filters, fuel pump, take the air horn off the 4bbl carb and watch the floats work and couldn't for the life of me find what was wrong. Finally pulled the sending unit so I could see into the tank while shining a light down the filler neck. Turns out there was something that looked like a pencil eraser that was drifting around in the bottom. Every once in a while it'd get sucked into the pickup tube and shut off the fuel. Pulled that out and symptoms went away permanently.
Sure do love the EFI when it works, but I ain't good at diagnosis so when stuff goes on the newer vehicles I'll be on here or at fordfestiva.com whining for help.

 

[Inbred Redneck]

Just thought I'd update this thread. Finally decided that I'd chicken out at 242 miles on the trip odometer. Had a 1-1/2 gallon can I dumped on the tank after work and headed to town. Finally filled tank & can with 16.1 gallons at 265 miles, so that's 16.5 mpg. I would hope for better on the highway, but at least I know what I should be able to count on goin' back & forth to work.