I have been getting an intermittent DIC "Water in Fuel" message. After some hassle (as described in another posting) I was able to drain the fuel filter.

What was surprising was that only a very small amount of fuel drained out. I would say less than 1/8 of an oz. Only a small amount dripped out, then stopped. Then some more dripped out, then stopped. I actually unscrewed the wing nut all the way out. The tank fuel cap was unscrewed, as documented in the owners manual.

Is it normal for such a small amount of fuel to drain out of the fuel filter when the drain valve is opened? I was expecting much more.

I poured the drained fuel in a clear shot glass, but could not see any signs of water. I started the truck and the "Water" message was not displayed. However, after driving for a few minutes, the "Water in Fuel" message came back on. So now I am trying to figure out, is there water in the fuel, or is the sensor faulty?

Let me add that I had been operating the truck in a thunderstorm (high humidity) area and I had added Stanadyne additive (a demulsifier) a couple of times over the last five fill-ups.

So, should I have been able to drain out more fuel, and do I have some water in the fuel or is the sensor bad?

Thanks,
Bruce H.

On Edit: The supplement manual says to "Remove the fuel cap", but it does not mention anything about loosening the bleed screw. I suspect a vacuum in the filter prevents fuel from flowing out the drain. Does the proper procedure include opening the bleed screw to release the vacuum and drain more fuel?

The manual does mention the option of pressing the priming pump several times, so I think I will give that a try in the morning.
Edited by: BH in AZ

Hello,

I went through the same thing a few weeks ago when my truck had a little over 1000 miles on it. One day I started getting a WIF light. I drained almost half a quart out and didn't see any water. The light went out for a day and came back on. I drained more out into a clear jar and let it sit for a day and still didn't see any water. A few days went by and then one morning the light came on again. I drained almost a gallon out and still didn't see any water. I ordered a new WIF sensor from GMdieseltech.com to see if the sensor was bad. I have never had the WIF light come back on though since then so I haven't replaced it yet. I did drain about another half a quart out two days ago and let it sit in a glass jar for a day. Still no water at all. I don't know if the little float was jammed in wrong or what.

The way to get lots of water/fuel out of the drain is to pump the primer while the drain is unscrewed a few turns. Works great. You don't even have to prime the system afterwards, it just starts up and runs. My fender liner also has a cut-out formed into it to get a small jar through and turn the drain, so I never had to remove the fender liner to do this. I can now drain a half a quart in maybe two minutes tops from start to finish, so I plan on doing this at least once a month for preventative maintenance.

My experience and Ccolmar's seem to be the same.

Using the primer pump as described by Ccolmar, I was able to get a good flow out of the filter this morning. I drained about 11 oz into a glass but there were no signs of water after it sat for awhile. I then added a cap full of Stanadyne additive demulsifier to see if it would take any water out of suspension. Again, there was no sign of water.

I took the truck for a drive and the WIF message came on after a few miles. I would press the steering wheel DIC button to display the mileage and the message would disappear, but the WIF message did display a couple of more times during the drive.

Here is what I am think my be happening. As I recall, the message has been appearing most frequently after adding the Stanadyne additive to the tank, and on the following fill-up. Now that it is humid, some condensation may be forming in the tank. The demulsifier in the additive is forming larger water particles that run past the fuel filter water sensor and set off the WIF message. The OEM fuel filter is failing to trap the water and it is sent to the injectors or returned to the tank. Since it has passed through the filter, there is nothing for me to see when I drain the filter. (Note: The truck does not have any additional fuel filtering, yet!)

If this is what is happening, then the Stanadyne demulsifier is doing a good job at what it claims. However, despite what GM says in it's additive bulletin, it is not the appropriate product if the OEM filter is unable to trap the water. I think it would be better for the water to go through the system in suspension or smaller particles instead of passing water particles to the injectors that have been combined together to form larger particles.

On the other hand, maybe it is just a faulty sensor?

I do not think I have a serious water problem since the fuel is always water free when I drain the filter, and that the WIF message is intermittent. Also, the truck runs great.

I think I will run a couple of tanks of fuel through the system to purge out the Stanadyne, then see if the message goes away. If not, then it is off to the dealer to see if they can test the sensor. (I have already talked to them, but basically they want me to prove to them there is no water in the tank before they will consider warranty service. The hoop dance has begun.)

Ccolmar, were you using any additives when getting the WIF message?

Have any other users of a demulsifier additive had this problem?

Is the OEM filter any good at traping water?

Thanks for any input. I would appreciate your opinions.

Edited by: BH in AZ

...
On the other hand, maybe it is just a faulty sensor? I do not think I have a serious water problem since the fuel is always water free when I drain the filter, and that the WIF message is intermittent.

BH,

I agree ... Seems like you have a problem with the sensor and/or supporting circuits. IIRC, the sensor is basically a float with a magnet and reed switch. It takes ALOT of water to get the float up high enough to trigger the switch. If you had that much water you would have seen it when draining the filter. To help isolate the problem you could try running with the sensor wire disconnected..If you still get the WIF message it would point to the sensor.

http://www.dieselplace.com/forum/smileys/Geek.gif Edited by: jbplock

Ccolmar, were you using any additives when getting the WIF message?


I have used Rotella DFA since getting the truck new in mid-May. I got a super deal on 2 of the big containers of it at Walmart this spring. I believe its a demulsifier like Stanadyne. I think when its gone I'm going to switch to Primrose based on feedback from this board.

I haven't had the WIF light now for at least two fill-ups, so I hope my problems are over.

jblock: I disconnected the sensor wire while the WIF message was being displayed (key turned to run and the engine off). When the wire was disconnected, the WIF message went away and the DIC display returned back to normal. When I reconnected the wire, the WIF message reappeared. When I drove around with the wire disconnected, no WIF message was displayed. After reconnecting it, the intermittent WIF message would show up every so many miles. I would assume that the wire has to be connected in order for the computer to receive a signal that something is out of the ordinary.

When shutting down the engine earlier today, the display was normal, no WIF message. However, when I turned the key to run a couple of hours later (without starting the truck), the WIF message was displayed. After another hour, I turned the key to run again (without starting the truck) and the display was back to normal. At that time, I drained another fuel sample. Again, there was no sign of water. I drove the truck some this evening and the WIF message appeared a few times.

The fuel in the tank still has about a 50% shot of Stanadyne. I need to burn off some more fuel to purge the tank of the Stanadyne, then see if the WIF message quits appearing after the next fillup.

I have reviewed some of the older threads discussing water in fuel issues. Some indicate the water accumulator has a float and some indicate that there are two electrodes sending a current throuh the fuel. Does anyone know for sure how the accumulator works? If it uses two electrodes, could an additive impact the current flow through the diesel fuel?

I am not sure what is causing the message but it does not appear to be a water issue. There were several notes that agree with jblock, saying it takes a lot of water to trigger the sensor. It is looking more and more like a senor problem.

Ccolmar, thanks for the update on the additive.

(If the dealer had been more cooperative, or maybe more knowledgable, I wouldn't have to be bugging all of you with these questions.) Thanks for the help!

Bruce,


It sure sounds like a bad sensor. I've looked at my sensor before and I'm fairly certain it contains a reed switch that is activated by a magnet in the float. I would just buy a new sensor and keep the old one as back up to use in case the good sensor breaks when changing filters. It would also save the hassle of going back to the dealer (who seems unexperienced with the Duramax). Good luck..


http://www.dieselplace.com/forum/smileys/Geek.gif

Problem resolved!

I ran out the additive and the WIF message was still appearing intermittently, and still, every fuel sample was totally free of water.

I went the dealer this morning and told them there was more water on the surface of the moon than in this truck. The truck disappeared into the dealer back hole for a couple of hours, then reappeared on the other side.

The paper work said, tested water in fuel sensor, found bad. The sensor was replaced. I drove the truck all day and the message never appeared!!!!!

Bottom line, if you are getting an intermittent WIF message, but the drained fuel from the filter does not show any signs of water, then the sensor is probably bad.

Ccolmar and jpblock, thanks for the help.

Bruce,

Glad to hear your problem is fixed! http://www.dieselplace.com/forum/smileys/Approve.gif