I guess it depends on where you live. If it's a cold climate I figure you could use all the help you could get. It is a very simple replacement part to be honest.

I replaced mine just because and it was super easy

 

I am in Utah, temps have been in the teens at night lately. I think my starting problem is more related to the glow plug relay. But I think I will replace the heating element anyways. Just wondering if it's kind of like the AIH. Not really needed

 

Just wondering if it's kind of like the AIH. Not really needed

It's just like that. You have to remember that when the system was designed it took into account that these engines could go anywhere in the word and had to be setup for the coldest of environments. BUT,,, this was for #2 Diesel Fuel and we're now all using ULSD.

If you think about it, if it were to prevent Gelling why would it be in the Fuel Bowl? I mean, wouldn't the fuel lines (more exposed to the weather and in smaller, more thoroughly chilled quantities) be the first place to gell? So I think it's all about, filter-clogging, WAX and the current fuel is less prone to that in the first place.

What further convinces me is that fact that So Many have eliminated their Filter Housings altogether (for performance reasons), and are in the Coldest climates we have in NA, without problems.

With all that said,,,, I'd replace it, because it Is cheap and easy, and you retain the WIF function its connectors are also used for. I just would wait until it was convenient, like at filter change time

 

How is the fuel heater controlled? Or is it "controlled" at all? I just went and looked at my 99. There's only two wires going into the connector. One is the Fuse 30 B+ red/lt green, and the other (not sure of the color) is the input to the PCM for the Water In Fuel indicator.

I found a picture of the fuel heater element on Rock Auto. It has one wire lead, and looks like the element is grounded to the case.

So with only B+ power to the element, and the other side grounded to the case, is the fuel heater on at all times the IGN is on? Or is there a temp switch inside the bowl? It seems the #30-blowing only happens at low ambient temps, so the empirical evidence doesn't support it being on at all times.

Anyone really know how it's controlled? I'm not due for a fuel filter change for at least 24-30 months, and I'm not curious enough to open it up just to look for a temp switch. But I would like to know how / when it does come on. "How do it know?"

 

The control deal has bugged me for quite awhile. There are mistakes in the wiring diagrams for Engine Controls that show a "Fuel Heater" connection on the PCM connected to EOT sensor, and the Fuel Heater itself connected to EOT input. The Water In Fuel indicator in the cluster is wired to PCM "water in fuel ind", yet there is no sensor for the WIF input. I believe all references to "Fuel Heater" in the diagrams I have really should be "WIF", not "Heater". There are only 2 wires. One B+ for the heater, one for the WIF sensor. So there was no way for PCM to control the heater; not enough wires. (Not to mention this is a lot of current for a PCM output to control without a relay). The heater appeared to be powered at all times, but that didn't make sense that it would be. So I spent some time researching fuel filter heaters.

Enjoy..........

How is the fuel heater controlled?

The fuel heater is a Positive Temperature Coefficient element. A PTC is self-regulating. The closer it gets to designed operating temperature, the higher the resistance, and the lower the heat output. At initial power-up, the resistance is low and power consumption is high. Power consumption declines as it heats up, and at some point the draw is zero.

Here's a description of a fuel filter add-on PTC heater.

This link explains filter waxing, cloud point, and the temperatures at which it occurs.

So my instinct was correct. The fuel heater isn't "controlled" at all. It is always powered when IGN = ON. Eventually it turns itself off. The lower the temperature, the higher the draw. This has something to do with why it blows #30 when ambient temperatures fall. It draws more the colder it is upon power-up.

 

I'm not 100% on this,,,, but I know that element is not "on" yr-round or all those, first-cold-snap, fuse #30 problems wouldn't be seasonal. So, just like the GPR activation, the PCM must turn the heater on with some sort of temp requirements.

My assumption for the WIF is that the PCM simply monitors the resistance between the two connection points (when the element isn't energized) and when that resistance goes Low enough, with the presents of Water over that of Fuel, it sets the WIF light.

At least that's how I would do it so, it makes sense to Me :wink[3]:

 

I'm having a hard time wrapping my head around the idea that a shorted element (they're all "rotted" and corroded from sitting in water maybe) that causes the fuse to blow, is present at All times yet the system tolerates that short until the first really cold morning.

I haven't followed a wiring diagram, I'm not sure the '99 and my truck ('02) are the same on this (the fuses are different) but I agree, the current draw would not be going through the PCM directly. When it's Warm again (having a hard time working-up the enthusiasm to find-out now ), it would be interesting to find if that connector was always powered no matter the engine or outside temp...

 

it would be interesting to find if that connector was always powered no matter the engine or outside temp...

The connector HAS to be powered at all times, or it couldn't blow the fuse. The PCM can not control this directly because
A: There's no wire for it to do so.
B: PCM outputs do not control 10+ amps without a relay, and there is no relay.
C: The element is grounded to the bowl. There's only ONE connection to it. B+.
D: The wire color at the filter is the same color that leaves the fuse block: red/lt grn. If there's a relay in the circuit, the color will change. It doesn't.

As the ambient temperature drops, the element draws more upon power-up. If the element has deteriorated with age, maybe the first time it really turns on because it is cold, it swells up and shorts out. I don't know much about how PTC elements function. But I do know how wiring and PCM circuits function. There's only two wires. One is power to the heater, the other is the FIW indicator. The element is powered at all times, and is self-regulating.

I know I'm right. I answered my own question. It's a self-regulating PTC, and powered at all times.

 

I thought of another "test". Put your amp meter leads across fuse 30. Turn on the key, and watch the draw on the circuit. The colder the ambient, the higher the initial draw should be. If it begins at a high value, but drops off, it is the heater working and warming up. There's nothing else on #30 that could change the draw.

I just now this. It's about 68F right now. Well above where it should be on. Upon key-on, the draw was 359ma. After about 30 seconds it was 350ma. There are two relay coils (130ma each), not sure what the other 90ma is. But the draw definitely changed after key-on. Exactly what my studies of PTC elements say it should do if the element is above design temperature.

Now that I'm really curious, I'll try this test again when it's 0C or lower.

 

Early99psd what part of Utah are you in?

 

I am in West Point. I see you live here as well. Where are you at?

 

I'm in Layton but we are actually closing on a house in West Point on Monday and moving in this upcoming week. We are gonna be off 110

 

That's cool! I am about 4 blocks from the city offices. I see in your sig you have pis injectors, how do you like them?

 

I like them so far. I just put them in several months ago and have been waiting to get the new trans in before I really get on it or tow anything. Hopefully I can have it in here soon and test them out.

 

I have read a lot of good things about them. I think that they are the ones I am going with when I need some.

 

I would recommend them. I got mine from Corey at CNC fab. I would go with him. Are you wanting stock replacements or performance ones

 

Performance ones. I am thinking 160/30's. But not wanting to have to change transmissions yet. Mine only has like 40k on it.

 

If it was a performance replacement I think you would be good if you did a 6.0 trans cooler, aftermarket valve body, and a tune for it. My worry is for me is my pmr rods.

 

Ya I have the 6.0 cooler JW valvebody and a hydra with php tunes. I really like the way it shifts now. I just can't make up my mind on which ones 160 or the 175. I know the 160/30 is capable of 400 hp. I think my next upgrade will be a hpop. Being that mine is a e99

 

Apparently i can't type on my phone. What i meant to say was i think you would be fine with 160 or 175's if you had the cooler VB and Tune which you do. So i think you would be ok. I would ask Corey@CNCFAB. He would be able to tell you. If you do decide to swap them out yourself and want some help just let me know since ill be right around the corner.

 

I will, thanks bud!

 

@early99psd Did you replace your fuel bowl heater. If not did you have an issues this winter with the temps and not starting. My fuel bowl heater is causing issues and it is unplugged right now but just trying to see if i need to replace it before next winter.

 

So my heating element ended up having a short in it. I didn't replace it and have left it unplugged. I haven't had any starting issues this winter at all. And haven't plugged it in once. But I have since last winter changed hpop with Corey's, new gp relay, motorcraft glow plugs and uvch. I have been running 5w40 synthetic oil as well. I think my starting issues were more of a hpop issue than anything. So far I am convinced that I don't need the fuel bowl heater.


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