Water in Fuel Light (being really tough to fix)

[cub124]

I really need help figuring this one out. Today I changed the primary and secondary fuel filters (the round style) and put a bottle of water remover in each tank but the WIF light is still on.

From everything I have read the WIF sensor on the 1982 6.2l trucks is in the tank. However my truck only has one wire coming from each sattle bag tank. I also read that there is a drain for the tanks... I couldn't find it anywhere.

There is also a fuel line in the vally of the engine with one wire going to it. The line gets larger in one spot, I was told this is a fuel heater, It gets grounded through the secondary fuel filter housing but I noticed that this unit does not get warm so is this the sensor?

I have also had the engine running for about 4 hours since it has came on, drove it to work today.

:idea:

 

[WarWagon]

Have you opened the water drain and drained some "stuff" into a glass jar and let it sit 10 Min? See if you really have a water problem by the water settling to the bottom with yellow fuel on top. This is where you need to start to see if you have a real water problem or a failed sensor or short.

Also a fuel system restriction from a plugged filter or fuel waxing plugging a filter can trigger the Water In Fuel light. Some years have this some not.

:suicide:

I don't know where to start on this. I'll take it easy. This is the #1 reason GM diesels failed in the market. Water remover is for gasoline engines and specifically so water doesn't freeze in the fuel line causing the engine to stop. It mixes the water into the fuel so it is carried to the carb and run out of the system with the fuel into the engine.

On a diesel engine water having zero lubrication value and being a larger molecule than diesel fuel does some funny things at the 1800+ PSI the fuel lubricated injection system runs at. Funny expensive things.

This is why the "water in fuel" light is red just like the No Oil pressure, Hot, and generator failure light. It means "stop!" the vehicle ASAP as damage can be done. Yellow like service engine soon and low fuel is, well yellow caution.

So the first line of defense is a sump in the bottom of the fuel tank so water settles to the bottom and the fuel pickup is over any small amount of water in the bottom of the tank. Then the tank sock rejects some water and has it fall to the bottom of the tank. Any water getting by this hits the water separator and fuel filter dual purpose element and falls to the bottom of the filter. When water collects here it triggers the water in fuel light by a float or other means.

If water gets past the filter it enters the injection pump that is lubricated by fuel causing scoring and corrosion. The advance piston would be an area harmed. The water then goes on to the injectors where it scores the pintles. Then think of water turning into steam due to combustion heat at the injector tip. It blows the nozzles off some types and can break the pintle in ours. Injector failure causes fuel to enter too soon like pre-ignition and the now excessive combustion heat on the compression stroke will melt the piston quickly. Failure of the complete engine from a bad injector looks like the pic in my avatar to your left.

You absolutely do not want water in your injection system. The above describes a small amount of water. A large slug of water will simply ruin the injection pump and likely break it's drive shaft from locking it up.

Using a product that "eliminates water" means it emulsifies the water in the fuel rather than letting it settle out. The water now travels to the filter and some water goes through it instead of being separated out. The alcohol used also attacks the governor flex ring on any pump made before ~1985 (or 1986?) that have not been updated with a newer, EID, part. So you have water and possibly another issue in the IP. then on to the injectors...

A product that separates the water is what you want to use. Some diesel engine stuff doesn't do that and I wonder how it stays on the market. Other ways to remove water would be to drop and drain the tank, use a water absorbing sock, or suck the tank dry through the fill neck.

Draining water at the filter and then confirming the light goes off is fine. Then start the engine and see if the light comes back on. Stop the engine after a couple min and check for water again. A third time of finding water means you got a big slug of water and need to drop the tanks to remove it - or remove it by other ways suggested above.

 

[cub124]

alright thanks, ill drain some fuel this morning and let it sit all day. When I bought the "water Remover" i made sure it said for use with diesel but wasn't sure if it would really do anything lol.

Im not sure where the water sensor is on this truck though, I understand that the fuel lubes they system and everything but i think its more of a wiring/sensor problem. Ill see tonight when I get home. I can also do a PSI test but I don't think its that either I have a new electric pump and it sure was flowing well when I bled the new filters.

 

[iamdave0887]

82-83 the water sensor was in the tank. 84+ it was in the box filter. 82-83 had the twin spin on filters, a better design IMO.

The restriction switch was from 84 up to about 88 or so when GM ditched it because the o-ring seal would fail and leak drain the filter about 1/2 way with the engine off, letting air into the system and causing hard starts. Been there with mine in winter '09.


I'm got a plan in my head to ditch the box style filter and put in a brand new GM 6.5 van cartridge style filter housing i bought at a swap meet for $50(came with 4 filters too). It had the heater and WIF all in the housing, so i wouldn't loose anything. Just have to see if it'll fit in the spot the box filter does.

 

[cub124]

Hey dave, I agree I like my filter set up, the one by the fire wall takes a little while to change but its not bad.

Everyone says the sensor is in the tank but I have had one of the tanks down before and the bed off, there is only one wire coming from the tank....This would be ohms for fuel level and if I switch tanks the WIF light wont flicker or anything.

Wiring wiring schematic anyone?

 

[cub124]

So when i got home today i was going to drain some fuel from the bottom of the tanks... (i found the drains) but the PO cut the drains from the tank :mad2::nonod: So I did some wire digging, I found only one wire going to the tank I had dropped which I recall for sure, the other had this wire above it, untapped it and found the other wire and the lovely crappy splice.... looks like I will be removing the bed sometime.
Now where can I get sending units with the sensors?


Yep no water there :hello:

 

[cub124]

So im still a little confused I pulled that pink wire off and the green wire which should be the fuel sending wire is still on the sending unit, but when i switch my right tank on the the fuel level goes wayy full. So I need to know what color wires should be for the water in fuel and how they are wired, also i need to know how the fuel drains are routed in because both holes are used on the tank as of right now.

 

[iamdave0887]

I think the wire to mine is a pinkish-red wire. There's no green wire going to my tank sending unit IIRC. I'll bet the green wire is the one for the WIF light.

All it does is ground out the WIF circuit, turning the light on. Remember, water conducts electricity, diesel does not.

 

[cub124]

yeah after i had posted i was looking around a little more, the green wire is the ground the pink wire with a black stripe is the fuel level indicator and there was 2 yellow wires that were cut short and tapped up to the sending unit wire which makes me think they have grounded out somewhere? as there is no sensor.

I wound like to put this into working order I dont really know if i need new sending units or not, also my guess is that the tank drains have a rubber hose with a T into the return side of the tank.

Really looking to figure this out soon! thanks for the help so far