Fuel filter change woes

[Dodgedart]

Every time I replace the fuel filter, seems like something goes awry. This time, I thought I just got away with a banged up hand. After I pushed the primer a zillion times. I finally got it started and I was checking the fuel filter canister for any leaks. I saw something glowing below the fuel filter and above the starter. I smelled smoke and discovered some burning wires at a connection on a module I didn’t recognize. I immediately turned off the engine and inspected. The two wires easily pulled out of this module but were burned back on the insulation. I cut the bare part of the wires back so no further shorting can occur and restarted the truck. It seems to run fine but I still don’t know what this device is for. It’s directly above the starter. I don’t know if I did something during the filter change or just pure coincidence. I’ve owned this truck since new. I was a TDR member 25 years ago but I can’t remember my username and PW, so I rejoined.
1997 dodge ram 3500 automatic transmission. TST cam plate upgrade to Bosch pump. 180k miles. thanks guys.

 

[Signal73]

Does it look kinda like this?

https://www.genosgarage.com/product...OGuNs24KK1g3fH9QiUw-W7feLbjrFUwZPxyHvYL2PQ8wM

 

[Cummins12V98]

YEP, most likely the fuel heater as shown above. Unscrew the bowl then remove the puck with the two wire connection and throw it into the circular file. Now clean the surfaces and screw the cup back on.

 

[Dodgedart]

Bingo! That’s the culprit. I take it that it’s not that needed. I’m ok with deleting it if my truck doesn’t need it. I’m still wondering what happened. Maybe the heater element shorted out? Strange that it happened with servicing. Thanks for the quick responses.

 

[Signal73]

Bingo! That’s the culprit. I take it that it’s not that needed. I’m ok with deleting it if my truck doesn’t need it. I’m still wondering what happened. Maybe the heater element shorted out? Strange that it happened with servicing. Thanks for the quick responses.

It’s common for it to short out, the connectors melt and it can cause a hard start condition. If you delete it you just need to remove the stainless stud it’s mounted to (I believe it’s an Allen head accessible from the bottom) then the cup will screw right back up.

 

[Dodgedart]

Update: I did drop the bowl and also the puck held by the allen screw. Just for kicks I ohm’d out the heater element and got 1.2 ohms which isn’t a dead short but close to it. I would expect 8 to 10 ohms or maybe higher. I opted to clean up and keep the screen strainer, it had some gunk but not horrible for over 27 years with no attention. My issue now is back to priming fuel. The priming plunger is making a hollow sound that it wasn’t making after the fuel filter change the other day. I thought the heater bowl might not have been seating so I pulled it again but still making a hollow sucking sound. Any suggestions? 1997 3500 4x4 5.9 diesel

 

[Grumpy8811]

Update: I did drop the bowl and also the puck held by the allen screw. Just for kicks I ohm’d out the heater element and got 1.2 ohms which isn’t a dead short but close to it. I would expect 8 to 10 ohms or maybe higher. I opted to clean up and keep the screen strainer, it had some gunk but not horrible for over 27 years with no attention. My issue now is back to priming fuel. The priming plunger is making a hollow sound that it wasn’t making after the fuel filter change the other day. I thought the heater bowl might not have been seating so I pulled it again but still making a hollow sucking sound. Any suggestions? 1997 3500 4x4 5.9 diesel

doing the basic electrical math 1.2 ohms at 12v is a 10 amp draw or a 120W heating device.. if it was designed for intermittent durations it might actually be correct resistance reading.. but question is, do you need a fuel heater? did you try lubing the priming plunger with good old WD or equivalent?

 

[petersonj]

doing the basic electrical math 1.2 ohms at 12v is a 10 amp draw or a 120W heating device.. if it was designed for intermittent durations it might actually be correct resistance reading.

I think that you are correct.

Lots of people think that the unit shorted out because of heat evidence at the connection point. That is not usually the case. The electrical connections become corroded and start offering resistance. This will result in excessive heat at the connector.

Example: 60 watts of power are heating the poor connection and 60 watts of power are going to the heating element - total of 120 watts. The connections get destroyed, but there is no short circuit.

- John

 

[GAmes]

The priming plunger is making a hollow sound that it wasn’t making after the fuel filter change the other day. I thought the heater bowl might not have been seating so I pulled it again but still making a hollow sucking sound. Any suggestions? 1997 3500 4x4 5.9 diesel

Regardless of the sound does it prime and start?

 

[Dodgedart]

I finally figured it out. It was my fault. For some reason I thought the puck sat in the fuel bow, not an actual spacer like it is. I reinstalled the allen bolt adapter and the bowl never seated correctly. Since it’s a 4x4 and difficult to see or reach, I couldn’t see this at first, until I took a good look at the heater puck and realized it was a spacer. The sound I heard was the primer sucking air. All good now. I agree what was said about the connection having resistance. It could have had years of corrosion and then with the fuel filter change dripping some fuel on the connector, thermal runaway. I live in California, it snows here, but seldom below 30 f. I think it will be fine. I have a diesel tractor and diesel generator and neither have fuel heaters.

 

[AH64ID]

Dose your fuel in winter and you’ll likely be alright, but personally I’d get a new fuel heater.

 

[BigPapa]

Dose your fuel in winter and you’ll likely be alright, but personally I’d get a new fuel heater.

Removal of that heater on the 12-valves has been SOP as long as I can remember. He's in CA. Unless he travels to the great white north, he'll be fine without it. I pulled mine early on and never had a gelling issue, temps occasionally around zero here in TN.

 

[GAmes]

Dose your fuel in winter and you’ll likely be alright, but personally I’d get a new fuel heater.

Why? I removed mine a couple decades ago and have started the engine without issue when it was -14f. In the words of Joe G, a previous TDR member who wrote an article about the 12 valve fuel system;

"The fuel heater is actually worthless. Just a problem waiting to happen. It does not help to start in
cold weather. There is about a quart of fuel between the fuel heater and the injectors. The fuel
filter is full of cold fuel. So are all the lines, the lift pump, and the injection pump. So when the
truck is started it is started with cold fuel. It takes a lot of pumping with the starter to fill the fuel
filter when it is changed. It would take that much pumping plus some to get warm fuel from the
fuel heater to the injectors. I recommend removing it and throwing it away."

(2) Joe G's fuel system writeup | Cummins Diesel Forum

 

[AH64ID]

To each their own, but I stand by replacing it. Starting, which is the entire focus of that quote, is a laughable reason to remove a heater.

It only takes one tank of improperly winterized fuel to regret the decision to remove the fuel heater.

Anyone remember the mass fuel gelling issue with the rear filter was added to the 4th gen, but the heater was not enabled in the BCM? That alone should be enough justification to maintain a fuel heater.

Additionally with the presence of bio fuels, like in California, a heater is more important than ever.

The heater has a thermostat, doesn’t it? So at the time of filter replacement the fuel was cold enough to warrant heater change. Which is lucky for the OP because replacement in the summer wouldn’t have shown him the issue.

Removal feels kinda like the FASS/AD craze from 15-20 years ago to improve filtration when the filters that came on them actually had worse filtration than OEM filters did.

But at the end of the day it’s the OP’s choice.

 

[petersonj]

a previous TDR member who wrote an article about the 12 valve fuel system;

"The fuel heater is actually worthless. Just a problem waiting to happen. It does not help to start in
cold weather. There is about a quart of fuel between the fuel heater and the injectors. The fuel
filter is full of cold fuel. So are all the lines, the lift pump, and the injection pump. So when the
truck is started it is started with cold fuel.

It is my understanding that in the early stages of fuel gelling, it is wax crystals that start forming in the fuel. The crystals cannot pass through the fuel filter which is why the fuel heater is located where it is. The wax crystals will plug the fuel filter, but they will not affect the rest of the fuel system as far as fuel flow.

In the late 80's I lived in Leadville, Colorado at 10,000 ft. I owned a Ford van in which I installed a 4BTA 3.9L Cummins engine - no fuel heater. The van had two fuel tanks. I was always careful to buy fuel from stations that blended #1 and #2 diesel fuel.

One cold winter day I left on a trip from Leadville to Crested Butte via Gunnison on the west side of the Continental Divide. Gunnison reported -40°F that morning. One fuel tank was empty, the other was about 3/4 full when I refueled in Poncha Springs on the east side of the Continental Divide - temperature about 15°F. I decided to fill the empty tank and not touch the 3/4 full tank because I didn't know the quality of the fuel at that lower elevation.

So I continued on the trip pulling from the tank I just filled. When I dropped down into the Gunnison valley the temperature fell to -30°F. Shortly after I turned north heading to Crested Butte, the engine faltered and died by the time I stopped alongside the road. I made one attempt to restart the engine, which I knew of course would not start. I switched to the other fuel tank (the good fuel) and waited patiently for 15 minutes to allow the engine to transfer some heat to the fuel filter housing. The engine started and never missed a beat for the rest of the trip.

If the cold fuel truly had affected all of the other lines as mentioned in a previous post, then I would have never been able to restart the engine and continue driving.

I believe a fuel heater has merit.

- John

 

[GAmes]

It is my understanding that in the early stages of fuel gelling, it is wax crystals that start forming in the fuel. The crystals cannot pass through the fuel filter which is why the fuel heater is located where it is. The wax crystals will plug the fuel filter, but they will not affect the rest of the fuel system as far as fuel flow.

- John

The fuel heater on a 12 valve doesn't heat the fuel in the filter. It is located prior to the lift pump and will only heat fuel that is pumped into the filter. If the filter is gelled, there is no benefit. The engine will not start until the engine is thawed out. In addition, the heater puck is a known entry point for air, which will prevent the engine from starting at all, no matter the weather.

I use anti-gel additive if I am buying fuel in the south and going north in the winter. I can go from central TX to the SLC area without refueling. If my destination is the PNW I don't us any additive when I refuel there. If my destination is Calgary I will. Like I said, I have been without a fuel heater for over 20 years and have never had a gelling issue, even when traveling in the Great White North.

 

[AH64ID]

Heating fuel going into the filter is the way you want to do it. While it’s possible to gel prior to starting most gelling occurs while running, and what you prevent heating the fuel as it enters the filter.

 

[GAmes]

Heating fuel going into the filter is the way you want to do it. While it’s possible to gel prior to starting most gelling occurs while running, and what you prevent heating the fuel as it enters the filter.

I beg to differ. I once filled both tanks in Mississippi where the temps were in the 50s. Two days later I was in IN where it was -5. I didn't think to add any anti-gel to my aux tank, nor my main tank. I filled my main tank in IN and headed west with a trailer. Somewhere in ND I switched over to the aux tank. It is a gravity feed system with a filter between the aux tank and the main tank. The filter was clogged with gelled fuel. I ended up hauling 50 gallons of fuel all the way to Seattle where the temp was warm enough to thaw the fuel. That is when I learned that southern fuel is treated differently than northern fuel.

The second reason I disagree is once the engine is running hot fuel is returned to the tank so the odds of it gelling while on the way to the lift pump, then to the filter are slim. That is why the Mississippi fuel in the main tank didn't gel while I was in below freezing conditions.

You also mentioned bio-fuel in a different post. All diesel in WA and OR is mandated to be B5 and many pumps in other states have a decal to let customers know the fuel might contain up to 5% bio. My fuel of choice in OR is B20 because it costs less than the B5. It costs less because bio is subsidized by the feds. I think of it as one way to get some of my tax dollars back. Once again, I don't add anti-gel to fuel I purchase there. It is already treated.

 

[AH64ID]

Around here you don’t hear about many folks gelling in their driveway, it’s always on the road where the filter eventually plugged even with hot fuel returning from the engine. That’s why the heaters are important. Sure a filter can gel just sitting in the cold, but my experience is that they plug slowly when not heated and the fuel stops flowing at the first unheated filter in the supply line.

B20 gels much easier than B5 or 100% #2. I like to run B20, but won’t in winter. I’ve had it gel even with extra additive, but that was long enough ago I’m not sure the additives were properly formulated to work on B20.

 

[GAmes]

..... the fuel stops flowing at the first unheated filter in the supply line.

If that were the case the heater would once again be worthless. There is a prefilter prior to the heater puck.