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Discussion Starter #1 (Edited)
Filled up both tanks yesterday afternoon (Exxon) 35 degrees, drove home about 20 miles, used the truck around the house to move some things later in the day. Parked it for the night low temp of 20ish, cranked up fine this morning and drove fine 10 miles to drop my kids off and then the next 6 miles to the jobsite. Came out 4 hours later to go get my kids temps in low 20's with wind-chill around 10. Made it about 4 miles and noticed the fuel filter light came on. Filter (Motorcraft) has been in for about 7K. Made it to my parents house, hung out for about 3 hours temps still in low 20's. Fired it up light was gone, made it about a 1/4 mile up the road and the light came back on at 1/2 mile the truck bucked kicked and barely made it off the road idled fine for a few seconds before it died. Got out and pulled the filter it was dirty but nothing bad. Got my boy to crank it with the filter out and the fuel level at a 1/4 of a bowl did NOT rise. Decided to chance it put the cap back on and I cranked it and it fired right up. Threw it in gear and took off and made it about 100 feet before it bucked kicked and barley got off the road and died. I checked the bowl again still 1/4 full and does not fill while cranking, pushed a wire into the Shrader valve while cranking and got no fuel or pressure. It will catch like it wants to start but will not fire. Got my dad to tow us back to their house with the tractor. First time in over 14 years of ownership it has ever left me where I could not drive it to where it could be fixed.
This is the 3rd fuel pump since I have owned the truck I think this one is about 6 years old probably a Nappa. I have noticed some wetness under the pump recently and was pretty sure it was getting time to order another pump from diesel o-rings (did my other truck last spring). I have never had one just give out though most of the time they just leak like crazy to I get tired of the mess and replace them. It was getting to cold and dark to really start poking around once I got it off the road. No check engine light and I did not have my ELM with me go figure. I at fist thought bad fuel, or ice in the fuel but I had no water in fuel light yesterday. I have a jug of 911 sitting on the shelf, and I did not add any Power Service supplement white bottle yesterday like I always do in the winter. Gelling is not a problem around here, but bad fuel sometimes is.
Both tanks are full, both tanks are NEW, both tanks have NEW fuel pick up feet, Both tanks have had at least 3/4 of a tank of fuel ran through them before yesterday. I have not tried switching tanks yet, but I have never had A problem with the transfer switch. Only modifications are 203 t-stat intake and exhaust.
With the fuel light coming on I am thinking something fuel, but I will put Forescan to it tomorrow to see if anything else shows up. Anything else I might be missing? Truck ran great for about 60 mile trip yesterday.
 

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Forscan might tell you if something else is wrong but it won't tell you anything about the fuel system (PCM doesn't monitor fuel pressure). You could always see if it will pull fuel from a separate container straight into the pump inlet. Cheers!
 

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Discussion Starter #3
Thanks Patrick, I meant to say I would put Forescan on it and see if anything "else" shows up. Been a long evening!
 

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Discussion Starter #4 (Edited)
Tried cranking it with fuel bowl open this afternoon temp 35 degrees , high teens last night, still no filling of the bowl. filled it manually with 50/50 diesel diesel 911 replaced filter, had my dad crank it while I bled the air out of the valve. Took about a minute of on and off cranking before it finally started. Ran like crap for about a minute before it cleared up. Let it run for a few minutes and shut it off, fired right back up. I then realized that I have no Water in fuel idiot light when cranking. I have no idea how long the bulb has been burnt out, but this must have been the issue I missed. Going to replace that bulb tonight (if I have a spare). Feel pretty stupid to have missed it not being lit up, I usually catch stuff like that pretty quick. Hopefully not to much damage has been done to my injectors. I did test my fuel pump and either the two gauges I used are wrong or I am missing something, but I only have 17p.s.i while running. I am going to look more into this later. Truck still runs fine. Forescan showed no other issues. Truck made it home tonight (10 miles) with no other issues.
EDIT,
Switched several bulbs around and still no WIF bulb light when cranking, went to the other truck and same thing. I know I am not dreaming about them lighting up while cranking at one point while owning them.
 

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Mine goes on for a second immediately when I crank it after WTS (along with Fuel Filter). There is a solid state switch in the driver's side engine harness (or wiring issue too) that could be causing an issue if it never comes on. See attached for what it looks like. I've also attached the diagram. Cheers!
WIF Module.png
 

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Discussion Starter #6
Thanks again Patrick! I will start tracing the wires. Looks like I should have power while running on one side of the switch, off of the diesel warning light fuse. Is it possible to jumper wire across the connection to see if the bulb lights up? That would show the wiring to the bulb was good. I do not think the problem is in the ignition wire because the engine and filter light flash when cranking. I am leaning more to the switch being the problem area. Please let me know if I am reading this wrong.
 

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The fuel filter light is connected to a vacuum switch. When it activates, it generally is because there is excessive vacuum in the fuel line that runs from the tank to the vacuum switch in the fuel bowl. Common reasons for the excessive vacuum might include an obstruction caused by junk in the fuel tank, potentially resulting form a deteriorating pickup screen putting plastic bits in the line, microbe masses in the fuel, ice, or whatever obstruction that might cause the vacuum to rise above sensor limits.
 

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The problem with his is the WIF light not coming on at all. It should at least come on momentarily when initially cranking the engine to start it. I would think it should light if you jumpered the R/Y wire (circuit 640) and the R wire (circuit 643) at the WIF Switch module connector. Just disconnect the module and jump those corresponding pins in RUN or START. The module should be on the drivers side of the engine (under the decorative engine cover if you have it) just aft of the HPOP reservoir in the harness. Cheers!
 

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Discussion Starter #9 (Edited)
Patrick I just got home and looked under the hood before reading your last post. I was looking on the fuel bowl. The black thing in your top picture is the Switch? Is it located right near the wiring connection by the HPOP reservoir? Once I cross the wires and check the light, I should be able to work back to the switch right? Then next would be the sensor itself.
EDIT
https://puredieselpower.com/94-97-ford-7.3l-powerstroke-water-in-fuel-module.html
Steep price, especially if I need 2!
Tasca has it for around $37
 

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The black thing is the solid-state switch. I don't know how you can test the sensor itself (not counting doing something dumb like filling the bowl with water :oops:). Assuming the wiring is good, jumping the pins I mentioned above should light the light. If it doesn't you would need to check the wiring from module connector to the bulb, bulb to ground,circuit 41 as well as seeing if there is voltage on the 640 circuit pin in RUN/START. After that, I don't know what would happen if you grounded the lead to the sensor (the sensor is a thermistor). Wouldn't want to damage a good module. I would probably then check the wiring from module to sensor and circuit 41 (module to warning lamps display.. Cheers!
 

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Discussion Starter #12
Patrick, I jumped the RY and R wires WIF light came on with ignition on. Makes sense to me looking at the chart. At this point I think I am going to order the switch from Tasca or or somewhere like that. Try it on one truck if it works I will order another one for the other truck. As always Thanks for the great information! Even after owning one of these trucks for 14 years I still learn something new every week, especially as they get older.

Craig, I Have never had a problem out of it before, but never hurts to test it once in awhile.
 

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Do you have the part number for the switch/sensor?

RiffRaft Diesel sells OEM sensors and they have a WIF sensor listed, but I believe it is what actually screws into the bottom of the filter housing.

 

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Discussion Starter #14
Thanks Bugman, I ordered a OEM switch online for around $46 shipped. If I need the sensor I will look at the Riff Raff one. I need to order another turbo boot kit from them anyway.
 

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Discussion Starter #16
Decided to check fuel pressure again tonight. Tested my 303k truck with a 6 month old Diesel O-rings pump. 45p.s.i. ish running. Went to the truck in question and it is only reading 14p.s.i. running. I am surprised that it is actually even able to drive. I pulled the new fuel filter and it still looked new, fuel level was higher then the other night, cleaned the screen it was dirty but nothing out of the ordinary. tested again and still 14 p.s.i. There was no vacuum on the fuel bowl cap that would make me think there was an obstruction. There was some vacuum the other night when the Fuel Filter light lit up, but I do really believe that I had some ice in the system then.
At this point I know I probably have a bad WIF switch, will confirm that when the new one gets here. Also I believe that my fuel pump is on its way out. Kinda glade that the truck left me on the road the other night now. Who would have guessed.
 

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While not on a diesel, I have seen bad fuel pumps right out of the box from the parts store.
 

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Discussion Starter #18
New fuel pump. lines ,and riff raff intake boot kit ordered today from Diesel O-rings. O-ring's wanted the same price as riff raff for the boots so I decided to order all in one order (also got free shipping), both great companies to order form. Always happy with my orders. The wait begins to see if it will all come together once it all gets installed.
On another note is Tymar still in business? It has been a long time since I have heard about Dale. I was thinking about updating my 303K truck with the intake and maybe downpipe.
 

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Dale still has his Future Home Of Tymar web site up

Call him Monday and find out. 509.922.8785


I know that a few years ago I saw his intake systems being sold by a couple of vendors but I can't remember just who.
 
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