Help! Grandpa's 90 f250 no fuel problem

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Old 08-16-13, 07:16 PM
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Help! Grandpa's 90 f250 no fuel problem

Here's the story. Grandpa's got a 1990 Ford F250, 5.8L manual transmission, dual fuel tanks. Won't start, just cranks. Starts on starting fluid, but quickly quits. It obviously isn't pumping any fuel. No sound from the fuel pump. No fuel or pressure at the Schrader valve that I can tell. Last time I drove this truck (early spring) it worked fine. And as far as I know, no one has driven this truck since I parked it. Gpa's 99, so he can't be of much help. LOL

I've done some reading regarding the workings of the EEC relay and the fuel pump relay, and have done a little testing, despite the fact that I'm not electrically inclined.

I did find that with the key on, there was power at the fuel pump relay, at posts 2 (from the EEC Power Relay) and at post 4 (from the Ignition Switch). But what I'm having trouble with is whether or not the power is getting to the fuel pump.

From what I have gathered, the fuel pump is only accessible when you drop the tank. Is that correct?

So is there any method to send power to the fuel pump to MAKE it run? And I assume I could try this with either tank by flipping the tank switch on the dashboard? I mean, if one fuel pump is fried, maybe the other one would work?

And I suppose the other thing that I'm not considering is that this may not be a power problem, if it is a ground problem.

2 things I hate... auto repair... and 12V electrical. And this combines both.
 
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Old 08-16-13, 09:38 PM
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Normally the fuel pump is in the tank. Since this has two tanks, it may (no expert here) have two pumps. I would switch to the other tank and see if it starts. If not, start by checking fuses and then look for a broken or varmint chewed wire.

You can buy or make a simple 12 volt test light which will make your search for power a lot easier.
 
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Old 08-17-13, 05:37 AM
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try switching the tank switch and see if it starts......if not see if power on red/yellow wire that goes to this selector switch in crank position.if yes then check for voltage out on the two wires in crank position to the 2 rear pumps front pump should be red wire and rear pump brown/white.do you have a voltmeter?is this the 5.0l engine?
 
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Old 08-17-13, 05:42 AM
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I had to replace a fuel pump on my '88 F250, and it seems to me that was a relatively common problem in those years. As far as I know, the only way to access one, even to confirm that it's bad, is to drop the tank. I'm thinking that mine had two tanks as well, and that each had it's own pump, which seems to make the most sense, but can't recall for sure. There is one more thing that comes to mind though, which I would investigate first. I'm pretty sure that truck has a switch that shuts off the fuel in the event of a rear end collision, and I do recall hearing of some being sensitive enough that they wold trip when hooking up a trailer, hay wagon, or whatever. I don't recall having any issues with mine, but believe that the reset for this switch is in the vicinity of the passenger side kick panel, maybe behind it.
 
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Old 08-17-13, 06:04 AM
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There should be a fuel safety shut off switch as said.
It might be behind the passenger side kick panel and if you are lucky there will be a hole to reset it.
 
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Old 08-17-13, 06:15 AM
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if no power to pump selector switch on red/yellow wire in crank position......then the inertia switch would be suspect which feeds power to it or even before that the fuel pump relay.
 
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Old 08-17-13, 06:17 AM
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Thanks for the replies! Part of my problem with working on electrical is that I'm color blind, so it adds an element of insecurity / question to whether or not I have the wire colors right. Goldstar, I do have a test light, and autojoe, it's a 5.8L and I also have a voltmeter, although I only know the basics of how it works.

As for the fuses, the manual doesn't show any fuel pump fuse in the passenger compartment, and the one that is on the starter relay is fine, since it is supplying power to the EEC relay and fuel pump relay. Could be a broken wire though... one thing I don't have is a wire piercing probe, which looks quite handy for this sort of wire tracing. What's the best way to check voltage on a line that is covered in sheathing? Just nick it with a knife? Then what's the best way to patch that hole in the sheath? Plain old electrical tape?

The back tank is empty... I assumed that it's because that pump doesn't work. But rather than putting fuel in, maybe I could have someone listen at the lid when I flip the switch and turn the key to on. If the relay is working, they should hear something for 1 second, right?

I've also heard that if a helper holds his hand on the relay, that he should feel a "click" if the relay is working properly. I don't want to just order and replace parts. I haven't had anyone else with me to try this.

And pedro, I also was also reading about that inertia switch that has the reset button, but haven't located it as of yet. But that's definitely something I want to find and try.

These are the two pages that have been helping me along so far. Very clearly written, but it's a little over my head and still overwhelming.

Part 1 -Ford EEC Power Relay Test.
Part 1 -Ford Fuel Pump Relay Test.
 
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Old 08-17-13, 07:01 AM
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Had a few minutes to go check a couple things with my wife helping to turn the key. The relay does indeed "click" when the switch is turned to on. (more like a double click... on/off?)

When I am under the truck near the gas tanks, each tank will make one very tiny "click" when she turns the key on, depending on which tank is switched on. But other than the tiny click there is no whirring or pumping sound... not sure what the normal sound is supposed to be.

It almost leads me to believe that there is power to the fuel pumps, at least at key on. Not sure about during cranking though. And I still need to find that inertia switch. Won't have much time today to look at it.
 
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Old 08-18-13, 10:30 AM
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One thing you could try is whack the tank with a rubber mallet, I think while someone is cranking it. I don't remember what that does but it worked and it started right up.

They did have to replace the pump, it failed again in a day or two.
 
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Old 09-01-13, 04:35 AM
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harmie

Always start with the "Simple" things first! That's a good Rule of thumb for everything! A small Hand held volt meter-I prefer the old Triplette 310. It has very sharp probes that can be inserted into a covered wire, leaving very little damage, but since you will be testing near the Gasoline tank, I would suggest Covering the wire with tape at the testing site. Be sure that it is adjusted to DC Volts! Test as close to the tank as possible and you should have metal connectors instead of poking a hole in a wire. If you have your meter properly set, you should show 12 volts of DC Electricity. That is of course if the Starter switch is on and your Tank Switch is set to the tank you are testing! If you have the electricity, then either the Pumps are bad , the FUEL FILTER may be stopped up or the Auto Shutoff needs to be reset! First -the simple-change the filter, some times requiring a special tool. If that fails, the Auto Fuel Shutoff button will have to be located and reset!
Don't have a volt meter? Have you tried to loosen the fuel line at the tank and have someone crank the engine? That will let you know in a hurry, but is a bit dangerous if you can't keep it away from flames or the person doing the cranking can't hear you when you yell "Stop"! If it runs when you poor gasoline into the carb, it has to be one of these things! Just because you replaced the pump doesn't mean it is working! Advance Auto electric parts are famous for being bad out of the box! That is why I am sticking my neck out and suggesting you loosen the fuel line at the tank! This requires all safety measures possible, but is the second most simple test of all! Make sure there is no sparks or flames and get away far enough to avoid being sprayed with Gasoline! The Safety Shut Off Valve used to be under the dash-check an Owners Manual for the location or call your local Dealer and ask to speak with the Service Manager. Most help can be found at:Ford Truck Enthusiasts, 1948-2011 Ford F150, Super Duty & SUV owners community and information source. Covers F100, F-150, F250, Bronco, Ranger, Explorer, Expedition, Lighting, Escape and More. Good Luck and be careful when dealing with Gasoline!
 
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Old 04-25-14, 07:19 PM
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OK, so I haven't looked at the truck again until today. Grandpa passed away yesterday and now I HAVE to get that truck running in order to empty it. (it's full of branches!) So I looked at it tonight and plan to try again tomorrow.

I've dug a little deeper into this and am a bit confused by what I'm finding.

I took the fuel filter off and let it hang so as to tell if fuel is being delivered or not. It's not. 2 tanks. Rear fuel pump is unresponsive, and we don't care... we've only used the front tank... so the front fuel pump will "engage" (as in click) when the DLC terminal 6 is jumpered to ground. (at the ECM/EEC self-test plug) However it does not pump fuel. The tank is not empty and the line is not blocked. So does this necessarily mean that the fuel pump is bad? Or could it be a relay or something electrical?

To add to the confusion... as I understand it, grandpa had a "mechanic" replace the fuel pump but I'm not completely sure of that.

I've tried to follow the directions on pages 1-5 at this site.

When testing the Fuel Pump Relay:

wire 2 (low current circuit) shows 12V with key on, as it should.
wire 4 (high current circuit) shows 12V with key on, as it should.

When I perform "test #3" in the link above, where you jumper wires 3 and 4, the fuel pump clicks but pumps no fuel. The jumper wire (a paperclip) gets too hot to touch.

When I perform "test #4" in the link above, where you unplug the relay and then connect a 12V test light to the + battery terminal, then probe wire 1, the light is on when the key is on but goes out when I crank. I don't think this is right.

If I perform a further test with a multimeter, it seems that another relay (the EEC power relay probably) is controlling the voltage. When probing wire 1, at key on, wire 1 goes from 0V to .8V very briefly... a relay kicks in (EEC?), and then wire 1 reads 12V. If I then crank the engine, it again reads .8V... and if I quit cranking, the relay (EEC?) will click again and read 12V, and then at key off, it reads 0V.

I have pressed the button on top of the inertia switch and it seems like it's already depressed as it did nothing.

There IS spark to the engine because it will fire and run briefly on starting fluid.

When I perform "test 5" in the link above, with the fuel pump relay connected again, it will read 12V at key on for about 1 second... but then a relay kicks in (EEC?) and then there is 0V. THIS IS NOT RIGHT. His instructions say that with the engine cranking, I should have 12V.

I'm tempted to replace the relay but I hate to replace parts just to rule them out. I did see on youtube someone who suggested blowing it out with air and then storing it upright inside it's cover, rather than just letting it dangle.
 
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Old 04-26-14, 04:29 PM
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I dropped the front center fuel tank and put a new fuel pump on. End of problem. Old one ran but just didn't pump. Or maybe it couldn't generate enough PSI to make it past the check valve which is the first thing on the fuel pump outlet.

The sending unit/floats are fried, (pegged out past full) but at least it runs.
 
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