# 99 F350 fuel problems



## Coldiron (Jun 5, 2017)

So my truck started acting up acting like it was starving for fuel when you are going up a hill and then even on the flats it would miss bad but no smoke took it to a mechanic put it on his machine said that injector driver module was bad. Replaced the IDM and problem still was there. Figured it must be a filter problem but after replacing the fuel filter it didn't fix the problem so I thought there must be a filter in the tank somewhere. Dropped the tank pulled the fuel pickup and sending unit. There are two filters in the fuel pickup and return mixing tube. Both were completely plugged. Cleaned them out as best I could and put it all back together, hopefully problem is fixed now. Will test drive it in the morning.









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## 1Alpha1 (Jun 5, 2017)

Umm yeah, I think you just fixed the problem.


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## Tenderfoot (Jun 27, 2017)

I think you are a good candidate for the hutch & harpoon mod. Should help with this issue, especially if you put a strainer pre pump in the fuel line pickup between the tank and the fuel pump so it is easier to change in the future.


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## DR. P. Proteus (Jun 29, 2017)

Just because you read a code on the diagnostic computer it doesn't mean that that part is bad. Of course the IDM set a code! It had no fuel and knew it so it threw a code.

The only fuel filter on my 09 Dodge is in the tank. There is no way you can tell me that is good idea. Its been running rough off and on like a clogged filter and that will set codes for other sensors, misfire codes, O2 sensor codes.

Anybody can tell you what a gas tank looks like inside, its not a clean happy place.

The easiest thing to do it replace the part the code was set for but that is really not how it works... AT ALL.


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## blades (Jun 29, 2017)

ethanol strikes again.


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## Coldiron (Jun 29, 2017)

I thought ethanol gas was good for diesel pickups!?? Lol [emoji3][emoji3]

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## blades (Jun 30, 2017)

Guess I missed it was an oil burner, But EPA has struck there also - sulfur is/was a lubricant + choking the .... out of the new ones with their tier 4 specs. Always a great time watching you truck burn up in the drive due to regeneration.


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## Tenderfoot (Jun 30, 2017)

blades said:


> Guess I missed it was an oil burner, But EPA has struck there also - sulfur is/was a lubricant + choking the .... out of the new ones with their tier 4 specs. Always a great time watching you truck burn up in the drive due to regeneration.


In my experience, that is usually a block heater.


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## Coldiron (Jun 30, 2017)

Yeah I wish we could get the sulfur back. All the new emissions garbage has made for a lot of headache and fuel loss. My brother in-law paid 10k to get all his taken out on his 09 Kenworth and it paid for itself in 3 months just in fuel savings.

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## blades (Jun 30, 2017)

never had a problem like that, my units all have factory installed heaters for extreme cold weather course the auto speed control has been know to do that also on some models


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## blades (Jun 30, 2017)

Never understood how making an engine supposedly run cleaner but consuming twice as much fuel to do the same work was advantageous. But then I never was any good at twisting numbers


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## Tenderfoot (Jun 30, 2017)

blades said:


> never had a problem like that, my units all have factory installed heaters for extreme cold weather course the auto speed control has been know to do that also on some models


Block heaters that have frayed cords short on the block and it lights up an oil leak. Happened to a few 7.3s around me, honestly its usually what kills them. They all run till they burn down or get wrecked.


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## DR. P. Proteus (Jun 30, 2017)

Tenderfoot said:


> In my experience, that is usually a block heater.




Oh don't say that!

I thought it was gas too. I thought it might have been a steel tank that rusted or just old old gas.

I wouldn't think that little pump would stand up to diesel very long.


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## DR. P. Proteus (Jun 30, 2017)

Tenderfoot said:


> Block heaters that have frayed cords short on the block and it lights up an oil leak. Happened to a few 7.3s around me, honestly its usually what kills them. They all run till they burn down or get wrecked.




I was thinking also how the wires could just corrode and suck so much AC current to heat up enough to flash.

I have a dipstick style heater that glows red hot! WTF!!?? I never used the damn thing.


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## Tenderfoot (Jun 30, 2017)

DR. P. Proteus said:


> Oh don't say that!
> 
> I thought it was gas too. I thought it might have been a steel tank that rusted or just old old gas.
> 
> I wouldn't think that little pump would stand up to diesel very long.


The pump is actually on the frame rail, they are pretty reliable, but the quick connect fittings suck and those are usually what kills the pump. I had the same issue with my 7.3l. Its from a dirty fuel pump or just age. Those are pre screens to get debris out. The primary fuel filter sits in the valley of the engine. I did the mods listed (I own the same truck, just a year newer) along with a post pump filter and have had next to no issues after. The fuel system is really reliable and the fact it took this long to show issues is a testament to that. 

The block heater on a 7.3l is basically a hot water heater element sitting in the oil cooler so it heats the oil and the water side of things. The cords usually fray right where it comes out of the block or from rubbing on the block from vibration. On my truck I wrapped it in wire loom protector stuff to prevent that. I also inspect it regularly. If it comes down to it, you really will not kill yourself replacing it if you have to.


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