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So i have an 86 f250 6.9L deisel that I'm having a few problems and I'm needing some insight. My problem is I think my fuel pump went out but I'm not sure. Because I'm not getting fuel to anything. Ive tried bleeding the fuel system and there's no air or water in the system. But when I crank it. It wont start. And if it decides to actually start it doesnt run for very long. I thought about putting am inline pump in but I am not sure. Any advice or insight would be a huge help and greatly appreciated
Laughing Gas
Joined: Mar 2016
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yes, crank for 4 seconds - then reasonably quickly get out and press the shrader valve on the base of the filter housing .. it should spirt fuel .. or air .. or nothing .. ..
sounds like a bad fuel pump to me .. I can change one in 2 hrs without getting soaked in fuel - now that i've had to do it thrice .. good luck
sounds like a bad fuel pump to me .. I can change one in 2 hrs without getting soaked in fuel - now that i've had to do it thrice .. good luck
Mountain Pass
Joined: Sep 2015
Posts: 178
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So i have an 86 f250 6.9L deisel that I'm having a few problems and I'm needing some insight. My problem is I think my fuel pump went out but I'm not sure. Because I'm not getting fuel to anything. Ive tried bleeding the fuel system and there's no air or water in the system. But when I crank it. It wont start. And if it decides to actually start it doesnt run for very long. I thought about putting am inline pump in but I am not sure. Any advice or insight would be a huge help and greatly appreciated
You say you bleed the system, but there was no air? You sure, if you are not getting fuel, then nothing should have come out but air then?
The Injection Pump WILL despite all indications attempt to suck in fuel, it is not great at it, but even without a lift pump it can actually run the truck. So I have to ask, are you sure you are not getting ANY fuel?
Could you please elaborate on the method you used to bleed the system, for example, the valve on the fuel filter, or cracking open the fuel lines at the injectors while cranking?
This last part may seem silly, but in the interest of being consistent, have you visually inspected the lines all the way back to the tank? It would not be the first time in my experience to run into 3/8 gas fuel line spliced into a diesel. (it doesn't work by the way).
Really need more info to give you more of an idea on where to go, otherwise you are more or less just throwing parts at the problem, which is the expensive way to fix it.
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Well for a while it would start when I would just keep cranking it doesn't blow white smoke while cranking but it blows a but cloud when it first fires up. Also I tried bleeding the shrader valve so after cranking a few times and some fuel would come out kinda bubbly. But nothing but air comes out now. So I tried cracking the injectors and bleeding it that way I started with farthest from the injection pump and some more bubbly fuel came out then and stopped but it never got to solid fuel always had bubbles. That's what leads me to believe I need to put an inline helper pump
Laughing Gas
Joined: Mar 2016
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Well, it's hard to tell for sure if you are unfamiliar with the symptoms, but it does sound like it needs a fuel pump..
You can't just add a helper pump, because the old mechanical if defective can actually cause vacuum, negative pressure, completely restrict flow, and or blow the diaphragm sending fuel into the oil.
Replace the mechanical pump, just cut a gal water jug to catch fuel from dumping on you. Remove the batt cable hold bracket and ground for easy access.. Then it's simply a hose nipple and a wrench hose to fuel heater and 2 bolts and a gasket .. It's pretty easy to do, wish I could get a USA made pump, but at least spring for the "high dollar - 30ish"
Made in Mexico pump vs a Chinese pump.. Heck they might all be made on the same line but I used Delphi HFP907.
You can install a facet electric, but between the mechanical and the engine, not before it. Or delete the mechanical and put it on either end. But don't push fuel to the mechanical pump if the diaphragm ruptures you can flood your engine with fuel.
good luck
You can't just add a helper pump, because the old mechanical if defective can actually cause vacuum, negative pressure, completely restrict flow, and or blow the diaphragm sending fuel into the oil.
Replace the mechanical pump, just cut a gal water jug to catch fuel from dumping on you. Remove the batt cable hold bracket and ground for easy access.. Then it's simply a hose nipple and a wrench hose to fuel heater and 2 bolts and a gasket .. It's pretty easy to do, wish I could get a USA made pump, but at least spring for the "high dollar - 30ish"
Made in Mexico pump vs a Chinese pump.. Heck they might all be made on the same line but I used Delphi HFP907.
You can install a facet electric, but between the mechanical and the engine, not before it. Or delete the mechanical and put it on either end. But don't push fuel to the mechanical pump if the diaphragm ruptures you can flood your engine with fuel.
good luck
Logistics Pro
Joined: Jun 2017
Posts: 3,976
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From: Edmond, OK
Before you ditch the mechanical pump confirm that it is bad. Disconnect the fuel IN hose to the fuel filter and put it in an empty can. Crank the engine and look for positive flow into the can. If it's barely spurting then your fuel pump is probably bad.
Also, when I bleed the fuel filter I use a set of jumper cables on the starter relay to crank the engine while holding the schraeder valve open, This works a lot better than cranking the engine and then depressing the schraeder valve,
Also, when I bleed the fuel filter I use a set of jumper cables on the starter relay to crank the engine while holding the schraeder valve open, This works a lot better than cranking the engine and then depressing the schraeder valve,
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