Engine/Transmission (1994 - 1998) Fuel Heater Melted

[Joe G.]

It is ATTACHED to the body . . with the TORX screws,You can unscrew them if you wish (or can get to)

That attachment is your so called element,It does not open up the top of the body where the fuel is.

Unplug if you wish!!!! BUT WHY DO YOU WANT TO?????????

CUMMINS Put them there for a reason... ... ...

I wonder about that. From several posts by respected members it seems that the fuel heater is only used on the Dodge application. Maybe it's there because Dodge wanted it, not because Cummins put them there for a reason. I think Evan A. Beck recently posted that he only sees them on Dodges. Cummins engines without fuel heaters start just fine in minus temps. Remove the fuel heater and throw it away.

 

[Katmandu]

Why are these heating elements failing so much ??

And more importantly I believe... . When they do go bad, why aren't they blowing the fuse in the circuit ????

Nobody has addressed the root cause of the over-heated heating elements yet.

Why are these all going bad in the 1st place ???

 

[JJW_ND]

Fuel heaters good....

I have not ran any #1 or blended fuel in 9 years in my truck. I am sure I get away with this because of the fuel heater. Like someone else mentioned the heater gets you going from a cold start (cold fuel). If you have been running for a hour or more and drive into cold weather, the returning fuel that is somewhat heated will get you by. But when starting from siting all night or setting out all day and cold fuel, only the fuel heater will help "thick" fuel work.



You guys got me worried so I checked mine. First not a single drivability issue. Insant starts all the time. My only hint was last winter it seem like I was on the edge of gelling when my truck sat out in -15 or colder while at work all day and I drove home in the pm a couple times.



I felt all the wires and they seemed OK, a little stiff by the element, but nothing broke. I have never had any leaks. I unplugged the large gray connector that both the heater and temp sensor join and plug into and found two of the pins were alittle black ????. Because it seems like this is a pretty common failure and Im leaning towards picking up new parts to make sure it works.



jjw

ND

 

[Joe G.]

I'm wondering how much the fuel heater really helps start in cold weather. There is a lot of fuel between the heater and the injectors. The prefilter is full of fuel. Also the curved hose, lift pump, steel low pressure lines, filter, injection pump, and high pressure lines. It seems to me that it would take quite a bit of cranking to get warm fuel from the heater to the injectors.

 

[Missouri Mule]

Heat is energy and energy (heat) moves. The heater should keep warming the fuel until is is all the same tempature. Molecules that are warm don't like cold molecules next to them so enegy leaves the warm molecule to the colder molecule warming it up.

 

[Joe G.]

That's true, but I don't think it will happen fast enough to affect a cold start. It takes quite a bit of cranking to fill an empty fuel filter after a filter change. That is some indication of how long it would take for warm fuel from the lift pump to get to the injection pump. After a start hot fuel from the injector return fuel manifold goes directly back into the filter which should warm up fuel going to the injector pump pretty quick.

 

[Missouri Mule]

I will agree to that.

 

[JJW_ND]

Cold fuel

If the fuel is so cold ... and thick that it has trouble getting from the filter to the injectors, the heater will probably not make a difference. What I feel and have experienced is thick fuel struggling to get through the filter. Without additive and/or a fuel heater, "gelling" occurs at the filter, starving the system and engine dies. That is why sometimes, if one waits a short time for the heat to warming things up, you can get going again.



In this case (if this is what really is happening), I believe the heater "thins" the fuel just enough to keep it going though the filter. Back when my truck was pretty new, the same model year Fords had alot more trouble with running treated #2 (additive + straight #2). They needed to run a blend of #1 and #2 or straight #1.



jjw

ND

 

[Joe G.]

Just to keep this discussion going so we can learn something. It seems to me that a filter full of cold fuel is in between the fuel heater and the injection pump. I have noticed that it takes quite a bit of cranking to fill an empty fuel filter when you change filters if you do it that way. So in order for the warm fuel to get through the filter it has to push all or at least most of the cold fuel out or "tunnel" (I would have to have that explained if that is what is happening) through the cold fuel in order to be affective at the injection pump. In very cold weather I would think that would kill the batteries. The fuel heater is the FIRST thing the fuel from the tank gets to on the way to the injection pump. After that is the pre-filter, lift pump, and filter. The injection pump and all of these things will be full of cold fuel and will be cooling the heated fuel as it goes through them until they warm up too. If this is true then the truck has to start on cold fuel. Do you see a way around this problem?



Comparing a Cummins to a 7. 3 Ford doesn't work very well because they were notorius for being hard to start in cold weather. The glow plugs just were not up to the task.



Am I missing something?

 

[Hummin Cummins]

I'd have to agree, Joe. In my years of driving truck I have never had one gel up. (when using the proper additives and keeping clean filters on) I would be willing to bet that 99% of non-starts in cold weather is not enought battery to turn over fast enough. I have tried to find my "lope" when I start up cold, and I'm heading to the fuel heater next. I run additive year round, and my truck sat for 3 days at camp last year covered in a foot of snow with sub zero temps at night. Started up on second try when we were leaving. (not plugged in either)

 

[Missouri Mule]

It would seem to me that diesel (molecules) would asborb heat easily letting the tempature (molecule) increase quickly since it burns at a relatively low temp. (don't have the sciencetific data)

This should allow the heater to warm all the fuel in the system as long there is continous fuel in the lines (prime). Meaning the fuel in the tank could be brought up to 80 degress also.

Continous fuel in lines???

 

[Joe G.]

If fuel absorbs heat easily it will also give up the heat just as easy. In a very cold situation all of the fuel not in or near the fuel heater will be very cold. It is also mostly in steel which radiates heat very well too. The obstacle to getting warm fuel to the injectors is quite a bit of very cold fuel between the fuel heater and injectors. In fact, there is not nearly enough time to warm up the fuel before the engine starts if it is going to. AFTER it starts the fuel will warm up pretty quickly. One of the heat sources is the fuel return manifold that returns fuel from the injectors to the inlet side of the fuel filter.



I'm thinking that the fuel heater is rather worthless and prone to failure. I wonder how many are running around in cold climates with a failed fuel heater that didn't manage to cause an air leak.

 

[Katmandu]

FYI... . Here's a pic of the fuel heater below (Thanks to Joe for the pic) and the result of what happens when it overheats.

Someone suggested just plugging the leak with SuperGlue. I figured WTH and tried it.

My truck now fires right up the 1st crank and I SWEAR it is running ALOT SMOOTHER and has abit more get-up-n-go!!!

#ad

 

[JJW_ND]

Really cold temps

When temps go below -20 and stay there day and night is when you start to see alot fuel issues. Many rigs (big and small) parked along the highway a few miles from were they started. I agree starting is a whole seperate issue. But once running (in very cold conditions) a heater will keep you going. Once below -35 (rare even up here) even addtive plus #2 is on the edge.



The bad news is when you gell, it will be with the family on a rush to get somewhere, wearing your sundays best in a blizzard.



jjw

ND

 

[RON'S RAM]

I was increasing the idle on my '96 the other day and noticed some wires kinda dangling and looked at my fuel heater. The sensor on top of the fuel heater that senses the temp of the fuel had melted down flush with the fuel heater and had totally destroyed the connector. I went to dodge after a stop at Napa and they told me that I would have to buy the entire fuel heater assembly which includes the wire harness. So here's my question:



1. Does anyone know if I can get the wire harness and sensor without buying the complete assembly?



2. What would cause this to happen. I really don't want to put another one on just to have the same thing happen again.



Thanks for your input.



ETaylor

Etaylor, what did you end up doing? I just noticed the same problem on my truck. My sensor is also meted flush with the housing. I'm not sure, but don't think that part comes with a new heater or wiring harness and a complete unit may be the only fix besides removing it. I may just remove mine for now and replace it if there are any issues this winter. As other's have said, mine was probably not working for some time and I didn't know it.

 

[KWentling]

The sensor does come as part of the wiring harness. I replaced my heater a few years ago because of the famous air leak. I didn't know it was burned up until then. If it happens again I'll probably just eliminate it.



Kim

 

[RON'S RAM]

Well tonight I removed my fuel heater and what was left of the wiring harness. The heater was burnt inside and had melted enough of the plastic housing to let air into the fuel making it very hard to start the truck. I called the local dealer and they knew nothing about the heater/strainer. I gave him the strainer part # and he found the strainer kit but nothing else. I then called Cummins and he didn't know about it either. I gave him the fleetgaurd #'s and he said they are good and he would have to order the parts, not in stock. He couldn't find anything on the whole complete unit. So for now, I'm running it without the heater/strainer. If it becomes a problem this winter I'll put a new one back in. I've attached a few pics so others could see the problem and what the parts look like. To run without the heater, just remove the heater (black piece with plug), remove the threaded adapter, unplug the wiring harness and put the strainer back in place. If anyone has an exploded view of the heater/strainer please post it. Another thing I found out is that the relay for the heater is on the firewall next to the master cylinder in my truck.

 

[RON'S RAM]

Here are a few more pics of what was burned on mine. Thanks for everyone's input on this topic. My truck is starting good again and it didn't cost me a cent.

 

[RON'S RAM]

OOps, forgot to upload the pics before.

 

[Joe G.]

Here is what it looks like with the heater removed.



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