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Fuel system problem?

Its a little odd because the pictures in the manual for 84-87 also show only 3 wires on the WIF sensor. However, I also found reference to a potential WIF sensor also in the fuel tank that would also put the WIF light on if water that is allowed to sit in the bottom of the fuel tank rises to a certain level and needs to be siphoned out.

You may have something made in 83 that was a mix of both systems or something and the 4th wire somehow ties into the tank sensor.

Can you post the VIN number? 10th digit should be an E for a 1984 model,
 
Here some pictures if they help you at all

84-87 6.2 fuel filter.gif6.2 injector line torque.gif

Never know what GM would have done. Like the WIF in the filter could be the only thing that sends a signal to the indicator, but it can be activated by water or a signal coming in on this other wire.

Its a bit strange that the manuals I have dont say anything about it. But the database didnt have an actual wire diagram.

You may just have to figure out what is what by checking with a multimeter or inspection light. With the harness unplugged and ignition on see which two leads have power across them on the truck harness end, then like you mentioned jumper the power to the other one you think is the indicator light and see if the light illuminates in the dash. Then those are the three wires you need to hook up.

And there are 4 wires connected to the harness on the truck side of the connection?

Or you could see if your old WIF sensor will fit into the new filter housing.
 
Well I found this reference at least
The manual does say, "Note, The 1984 water sensor is an IC chip, 4 wire, 4 wire male connector voltage transient module. The 1985 and later sensor has discrete components, 3 wire module and a three wire 'female' connector."

So I still dont have a circuit diagram to figure out how to covert to 3 wire, but you can see if the 4 wire WIF fits on the new housing.

And if you can remove the vacuum sensor from the other filter you may be able to install that in line somewhere and still utilize that to show if the filter is clogged. I wonder why they removed that function in later models. That or find another vac sesnor that matches either Normally open or normally closed and splice it into the wiring.
 
I will see if the WIf fits in new filter, but where's the vaccum sensor? I looked at your diagram and only saw a restriction switch, heater and the WIF sensor.
 
The restriction switch is a vacuum sensor I believe. If the filter gets clogged then post filter will start reading a vacuum from the IP trying to suck the fuel through rather than the LP being able to push through and provide pressure.

I guess it is easy enough to figure out if one line goes to the WIF light in the dash and just run the power and ground too, to use the 3 wire WIF. Just not sure what that 4th wire was for.
 
Well I tried to test it but I just got more confused. The black and yellow together showed a voltage. The mystery colors are red and purple. The red was hot with the sensor in a cup of water and with it out. The purple wasn't hot with either sensor in water or not.

I did see on the back of the harness that the wires are labled

yellow= d
red= c
black= b
purple= a

But I don't know if that means anything.
 
I tested again and noticed that yellow and red both seem to have constant power, and black and purple both seem to be the ground. I tried my voltage tester with the four wires and got a reading off of all combination's using either red or yellow as a power wire. So there goes everything I thought I knew about electricity...haha. And all these tests were done with the sensor out of the water bowl. I think the sensor might not work or the bulb is blown since I didn't get the light to come on.

Update

I jumped the red and purple wires on the engine harness side with truck on and got sparks from both, I'm not sure if that sheds any light on the matter. I'm kind of scared to do any more jumping because I don't want to fry anything.
 
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What I am thinking is that 2 of the wires are probably power, one to power the sensor and one that is switched for the light, and when its not switched on it grounds the line that goes to the light. So you have an actual sensor power and ground and a switched power. So putting power to one of those wires should light up the WIF light. Do you get a WIF light bulb check when you turn the ignition on?

Or it could be backwards, that the light always has power and the switch in the WIF sensor grounds it. So you may have to ground one of the wires that has 12V on it, sounds like a short, but you will read voltage through a resistor and with no current being drawn because of a broken circuit you wont see any voltage drop.
 
No WIF bulb check when i start the truck. I didn't know it was supposed to do that. As for the wires, I'm going to tinker around a bit more later, I hope the bulbs not bad because it was a pain in the butt to take all that crap off to get to it.
 
All you have to pull is dash bezel. might have to take off the radio knobs too. is yours not right at the top with the GP light?
 
Ya it is, the hard part was the wires for the GP and WIF bulb were short and they slide into the bezel thing so it was just a tight fit. I guess I'm just complaining though...haha
 
Im not sure if you have to have the WIF plugged in to get the WIF bulb check. Although if you have never seen it then it is probably burnt out. What you can do safely to test if the light is always powered and the WIF sensor grounds it is use a test light, from each of the lines that had power and touch it to ground. The test light should come on and the WIF light if that is the WIF light wire. Thats safer than just jumpering it and potential short.
 
I got the new injector line today, got it up and running and everythings almost back to normal. The new injector line I got though was bent a little different than the old though. Accurate diesel told me that was the only one they have for the older 6.2's so I don't know why mines shaped differently. There is some extra tension between this line and the one next to it now, but it was the only way to make it work. I even tried taking them both out and putting them back on different ways but the way I got them now was the best. I'm thinking about buying one of these injector lines but i'm wondering how long is it actualy going to be good for since they say it's for "emegerency use"?
http://www.ssdieselsupply.com/product_305_Flexible_Injector_HoseTube.html

I guess I could call Boyces where I got the drop in motor and see if they have extra lines for sale. I did put the injector line clips back on but the only ones that would work were the ones that secured it to the other line. I couldn't get the one for the intake or the little brackets by the valve covers to work without bending the line.
 
Jamie Avant at dieseldepot has been through 1000s of these engines Im sure, thats his business, so he might know more and have parts. You can try emailing him, doesnt pick up the phone I hear. He responded to my questions within a couple days on email.

Is there any way to mix a line up with one for another cylinder? I dont know if any are bent similar enough to fit another cylinder but not quite right.

Having one of those emergency ones might be good to have if you can consider pulling the intake off and changing an injector line as side of the road maintenance. You might be really good at it now though.
 
I can try diesel depot, but I've had the same problem when I call, he NEVER answers or calls back. I don't think it would have been mixed up with another cylinder because it's so close to the same, but I will check tommorrow because you never know, especially with me. And ya I'm getting real good at taking the intake off...haha...I can almost do it with my eyes closed now.
 
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