Water in Fuel Light

[richp]

Hi,

This is a problem with an '01 K2500 with 155k miles. A couple of days ago, the water in fuel light came on steady. No running issues -- smooth idle and normal power. Temps were below zero, and I thought the float was maybe just frozen.

When the condition continued for another 20 miles or so, I changed the fuel filter. In the process, I checked the operation of the little float in the sensor on the bottom, and it seemed to move smoothly. (This is a 6-month old sensor unit, as the wires in the original unit had frayed and so I replaced it.)

The light was not on when I ran the engine after the filter change to see if the system was all purged of air. I went out a couple of hours later to move the truck in the driveway, and the light was back on.

Power Service white bottle as usual, fuel purchased from the same dealer I've used locally for years.

Any ideas? Thanks.

Rich Phillips
Member #27

[richp]

Hi,

I might add a couple of things.

The tank had been kept near full all winter, so I'm thinking the probability of condensation is low.

In line with the above, the last fill-up before this started was less than 4 gallons. And it ran fine the rest of that day for maybe 25-30 miles. So bad fuel is not totally precluded, but seems a bit less likely than if I'd just put 25 gallons in it the day before and this started pretty much right away.

With the light not on for 3-4 minutes of running after the filter change, me shutting it off and coming back a couple of hours later and the light is on -- I'm particularly puzzled. It just doesn't seem that much water could come through that fast without some change in the way the engine was running.

Other than taking to to a dealer, anyone have ideas?

Thanks.

Rich

[JohnC]

Open the drain and pump the primer and see if water comes out.

The filter is also a water separater. The light will come on when there is a little water in the bottom of the filter, way before it will affect running. The filter has to be nearly full of water before it could get into the engine. (You do not want this to happen!)

If no water comes out, remove the water sensor from the filter and test it.

[DmaxMaverick]

Once you confirm you do not, in fact, have a water problem, disconnect the WIF sensor harness at the filter. If the WIF indicator continues, you have a wiring problem, between the connector and PCM/BCM. If it only shows when it is connected, then the problem is the sensor, or the sensor connector.

[richp]

Hi JohnC and Dmaxmaverick,

Bled off the bottom of the filter today for a second time, and there was no water. Disconnected the lead from the sensor and the light went out.

So it looks like it's the sensor or the connector. I'll do a little more troubleshooting tomorrow.

Thanks for the advice.

Rich

[richp]

Update.

I pulled the filter and tested the float sensor. It gave continuity off and on as you would expect when moved up and down. Again, when I drained the filter there was no water.

Decided it's silly to keep fussing with this in the cold, even though it's an almost new part. Bought a new sensor at the dealer, put it in, and now it seems to be OK today. What tomorrow will bring, only The Shadow knows....

Rich Phillips
Member #@7