Water in Fuel
 

Have a Water In Fuel DTC

What I have tried:
1) Drained HFCM - saw about 1/2 teaspoon of water in the pint of fuel that came out
Cleared WIF DTC
WIF DTC came back after 1 mile of driving
2) Drained HFCM - saw about 1/8 teaspoon of water in the pint of fuel that came out
Added 12 ounces Power Service Clear Diesel to 20 gallons of fuel.
WIF DTC came back after 5 miles of driving
3) Drained HFCM - saw about 10 drops of water in the pint of fuel that came out
Twisted the corner of a paper towel and inserted it into the HFCM drain hole
Did this about 20 times, until no fluid showed up on the towel.
WIF DTC came back after 1 mile of driving

Question:
How effective is Power Service Clear Diesel?
How much water will it remove?

Question:
Is Power Service 911 better at removing water than the Clear Diesel product?

BK

I'm thinking you have corrosion and/or sludge in your HFCM. I would pull the cover and inspect. Some people bend the "straw" on a can of carb cleaner or even a penetrant and spray through the water drain hole to try to clean out the water reservoir and clean the sensor.

Thanks, bismic1,

I drained the HFCM again...did not even see a drop of water this time.

I sprayed carb cleaner into the drain hole (bent the end of the straw) quite vigorously about 4 times. A lot of carb cleaner flowed back out the hole, but no flakes of crud. I then waited while carb cleaner, and also diesel, came out the hole. I noticed that carb cleaner did not instantly combine with diesel in the drain jar, so I waited til I thought it was pure diesel coming out. I wasn't sure whether carb cleaner was good for the injectors, so I wanted to get as much of it out as possible.

I started it up and, within a mile, got another Water in Fuel DTC. I then stopped the engine, cleared the DTC and ran it again. Within about a mile and a half, the WIF DTC came back.

So, I think carb cleaner was a good thing to try, however, I believe the corrosion on the sensor is so thick, it won't be easy to remove it.

Is it possible to replace just the sensor, or must I buy an entire HFCM module?

John

Water In Fuel DTC resolved
 

So, I pulled the sensor and found out what the problem was.

The sensor is made of 2 copper electrodes. The sensor works by allowing a certain amount of current to flow between the electrodes. There are 2 conditions that must yield the expected results for the system to work:
condition 1: No water in fuel - a certain amount of current must flow between the electrodes while they are immersed in diesel fuel.
condition 2: Water in fuel - a large amount of current must flow between the electrodes, causing a Water in Fuel DTC to be reported.

If you never get water in your fuel, the electrodes will likely last forever, and the sensor and system will operate as intended.
If you ever get water in your fuel, condition 2 will yield a Water in Fuel DTC, which tells you to get rid of the water.
Once you have water in your fuel and the condition has triggered, you may be able to recover from it if you remove the water fast enough. However, exposing the sensor to water starts a corrosive process on the sensor, which will eventually cause it to fail. How long this takes I don't know, but its like what happens to a penny. It starts out a bright and shiny copper color and ends up being brown and eventually green. This corrosion is no longer conductive and this is what causes the sensor to stop working. It will no longer detect water in the fuel.
Ford engineers understood this and added another check, which is whether any current flows in the circuit while the sensor is immersed in diesel fuel. If no current flows under this condition a Water in Fuel DTC is reported. This means the sensor is bad, but there is no special indication that this is the case. What Ford could have done, but did not, is report another DTC, indicating the sensor failed.

On my sensor, and I think this is how all sensors fail, one and only one of the electrodes became corroded. It was very dark brown with a little green on it.
So, I scraped the corrosion from the electrode with a very pointed Xacto knife and re-installed it.
BANG! Problem gone.

In the process of removing the sensor and re-installing it, I messed up the plastic that is meant to hold it in. Even though it might stay in there forever, I'm going to replace it with a new one anyway...so, Ford gets their cut and I save having to buy a whole new HFCM.

And, by the way, I don't believe using carb cleaner is ever going to fix the problem. It may, in some cases allow it to work for a little longer, if your problem is microbial build-up. However, even in that case, the corrosion is not far from catching up with you and you should just bite the bullet and replace the sensor.

John

I didn't mean to say you should always replace the sensor if you ever get a Water In Fuel Diagnostic Trouble Code.
I meant to say, you should replace the sensor if you get the WIF DTC and you have crud build up in the HFCM module. No reason to replace the sensor if your HFCM was clean after you received a WIF DTC.
Another way to look at it...if you drain the HFCM and don't see any water in it and you are still getting a WIF DTC, it's time the replace the sensor.
My sensor lasted 135,000 miles before I replaced it. I encountered a WIF DTC more than twice previously and was able to resolve it by getting rid of the water in the fuel.

Glad you got it. Good information in your posts!