water in fuel light goes on and off
 

The water in fuel light came on during some heavy rain on Saturday morning. That afternoon I took the truck in to the dealer for it's regular service, and asked them to drain the water/fuel separator while they were at it. They actually replaced both fuel filters in addition to draining the separator, but since then the light has come on (typically after 20+ minutes of driving) and will stay on for 10-15 minutes and then go off again. Any thoughts why it would do that? Surely the water/fuel separator wouldn't have filled up again after only two days!

Did you fuel up somewhere different from the usual? Maybe you got a bad tank of fuel? I would drain the HFCM a few more times (very easy to do) and hope it clears up or possibly drain the tank and try a new tank of fuel. Did the dealer say wether or not they found water in there?

You may have to replace cover.

Only had the truck for four days, so don't have a "usual" place yet. Before I left the dealer, they topped it off (started with half tank) with biodiesel from the station right next to their lot. Since then I've put in another $50 in biodiesel from Wal-Mart's Murphy USA station (I'd prefer not to use biodiesel when possible, but right now finances are such that it's all I can afford... and I've seen enough other truck owners filling up at that station to know that they go through quite a lot of it).

Could biodiesel be causing the light to go on? I know that engine and sensor were designed before biodiesel existed...

I wouldn't assume that's the problem until after it's been confirmed that the WIF sensor has failed. I'd pull the water drain plug, confirm if water is/ins't present in the fuel; then I would clean the WIF sensor with carb cleaner before I just replaced the cover.I'm not saying your dealership's service department took your money for nothing, but draining the HFCM isn't that hard. Under the driver's door inside the frame rail is the HFCM (Horizontal Fuel Condition Module). Here is a photo it: http://dan.prxy.org/Truck/6L_bible_h...ply_System.jpg

Plan on draining about a pint to two pints out of the water separator. You'll want to look at what comes out after a couple of minutes. If it looks like Italian dressing, or doesn't smell like diesel you've got bad fuel.This is just my experienced opinion...there's nothing wrong with running the 6.0L on biodiesel blends. Yes, Ford only recommends up to B5 with the 6.0L...but I can assure you the engine will burn B100 all day long with minimum mileage loose (unlike E85). Mine loves the B20 that I buy locally and the only time I've had water in my fuel was form a low volume (not price) station that only had dino-diesel.BioDiesel has been around since about '98 or '99. So the fuel preexists the engine...but anything is possible. BioDiesel will carry water just like Dino-Diesel. For future reference, I'd try to buy diesel from a high-volume station. You want a place where the pumps are consistently going...less likely to have crap in the tanks.

Does your cover have the heater in it?

Fantastic info, thanks!

By cover with a heater, what are you referring to? The fuel cap? It looks like an after market cap and definitely doesn't have a heater... Is there a cover for the hcfm sensor that would have a heater in it? I haven't inspected it closely, so I would have to check.

The station where I have bought so far has a 40,000 diesel tank and it gets refilled frequently. (in comparison, that's double what most local stations have for their 87 octane gas... So quite a lot of volume... Being on the fire department has its pluses sometimes!)

The old HFCM covers had a heater in them that created wonderful chemistry projects inside the HFCM. The upgraded covers delete the heater. Drain some fuel out of the drain and check it out. It is also very easy to remove the cover and inspect inside. The fuel lines disconnect with the cheap plastic tools you can get from NAPA for under $5.00. Let us know what you find out.

The cover he's talking is the manifold cover on the HFCM. The original '03-'04...and I think '05 trucks....had fuel heaters on the HFCM. At some point along the production run Ford figured out heaters weren't needed and they were discontinued. The replacement covers and HFCM don't have the heaters. If you look at the top portion of the photo I posted you can see where the fuel heater is at. If you open the manifold cover to clean the HFCM manifold out...you'll need a new o-ring since it will have swollen after exposure to diesel; which means it will never reseal.As long as they have a high turn over on their fuel you should be fine in the long run once you figure out why the WIF light keeps coming on.

Ah, okay... that explains the hanging electrical cord there then... I must have one of the later ones without the heater, cause when I was looking at it, I noticed a cable bundle that looks just like the one in your pic that was just hanging loose... So no, there's no heater in it. Would it be wise for me to find one with a heater since I'm moving to 7500 feet elevation in the Rockies and can get 30 feet of snow in a winter?

And do I need to open the whole thing up to drain the water, or can I just pull the hex plug and let it drip into a pan?

Just pull the plug and let her run out.... a little messy if you don't have the plug upgrade from Ford. It honestly takes 5 minutes... if you do not have the upgraded HFCM drain plug, this would be a great time to put it in for next time!

Upgraded plug? Good to know about... I don't think I do (it's just a plug that I have to use a hex wrench to pull out, and I imagine putting it back in will suck). Is the upgraded thing something with a cock valve on it or something? I'll have to go by my dealer and see if they have it...

This fella right here......

Diesel Part # SB6E7Z9C082A - HFCM Water Separator Drain Plug Upgrade - Diesel Performance Parts


You can get it right from your local Ford dealer as well and it's not expensive. They are easier to take out than the little plug and it won't drip diesel and water all over the place when you drain the HFCM.

Here are the part numbers that should work at your dealer (sometimes the guy behind the counter isn't too bright and having the part number will speed things up for you).

Use the Int'l number at Int'l and the Ford number at Ford - see below.

Ford part number: 6E7Z-9C082-A
International part number: 2589259C91
List price is around $16.00

Awesome, thanks!