Seneca fuel water separator

[Mr Bill-JAY]

Has anyone here replaced the Detroit Diesel fuel water separator themselves? Any techniques, special tools, etc. you might want to pass along? Thanks guys. 2018 Seneca 6.7 Cummins

 

[Robbbyr]

Has anyone here replaced the Detroit Diesel fuel water separator themselves? Any techniques, special tools, etc. you might want to pass along? Thanks guys. 2018 Seneca 6.7 Cummins

I believe member Rustynuts has posted information regarding his Detroit water separator. Here is one thread where it is discussed.
https://www.jaycoowners.com/forums/f64/2019-seneca-s2rv-first-oil-change-62620.html

 

[Mr Bill-JAY]

Thanks! You guys are the best!!!!

 

[Rustynuts]

I have done mine several times. A few important things I’m not sure are in the other thread is when you go to drain the bowl, it can create a siphon effect and continue to drain and drain and never get empty. You need to crack open the vent plug on the top of the filter and this keeps it from siphoning from the tank. Use a piece of, I believe 3/8” hose to put on the drain to catch it in a jug and getting all over. You will need the wrench listed below to remove and install the bowl without damage. I fill the bowl with fresh diesel before installing as the primer is in a spot that gets tiring to pump up, it’s the silver button on top of the unit, pump it until diesel seeps out around the vent and then tighten vent.


https://www.amazon.com/dp/B00P3TLOH6?ref_=cm_sw_r_cp_ud_dp_FPZEHN7MZXKZG0B9F7NN

 

[EGChester]

Trouble with priming fuel water separator

Hey Brian:

I have an early 2018 Seneca with the same Detroit separator pump.
I have installed the new filter as you've described, but before I did, I filled it to the brim with fresh diesel.

Now I cannot get the stupid thing primed!! I've pumped that silver pump for 10 minutes or more and nothing seeps out the vent plug. When I remove the vent plug, it's bone dry inside.

Should I completely remove the vent plug on top and try filling that with diesel?

What happens if I try starting it before it is fully primed? Will I get so much air in my line that it will no longer start?

Thank you!

Eric

Golden, Colorado

I have done mine several times. A few important things I’m not sure are in the other thread is when you go to drain the bowl, it can create a siphon effect and continue to drain and drain and never get empty. You need to crack open the vent plug on the top of the filter and this keeps it from siphoning from the tank. Use a piece of, I believe 3/8” hose to put on the drain to catch it in a jug and getting all over. You will need the wrench listed below to remove and install the bowl without damage. I fill the bowl with fresh diesel before installing as the primer is in a spot that gets tiring to pump up, it’s the silver button on top of the unit, pump it until diesel seeps out around the vent and then tighten vent.


https://www.amazon.com/dp/B00P3TLOH6?ref_=cm_sw_r_cp_ud_dp_FPZEHN7MZXKZG0B9F7NN

 

[Robbbyr]

Hey Brian:

I have an early 2018 Seneca with the same Detroit separator pump.
I have installed the new filter as you've described, but before I did, I filled it to the brim with fresh diesel.

Now I cannot get the stupid thing primed!! I've pumped that silver pump for 10 minutes or more and nothing seeps out the vent plug. When I remove the vent plug, it's bone dry inside.

Should I completely remove the vent plug on top and try filling that with diesel?

What happens if I try starting it before it is fully primed? Will I get so much air in my line that it will no longer start?

Thank you!

Eric

Golden, Colorado

Not Brian but I believe you must insert and tighten the vent to allow it to draw from the tank when priming. Opening the vent stops the siphoning from the tank when replacing filter, but it goes back in when filter swapped.

 

[Rustynuts]

Robert is correct, the vent must be closed in order for the primer to fill the system.

 

[EGChester]

Fuel water separater problems

I'm back with the same problem, friends.

I have installed the new filter, filled the plastic container completely full of diesel fuel, and replaced it on the Detroit pump. It is the kind where the plastic container is on the bottom of the pump.

I have loosened the vent plug and pumped the silver pump for 10 minutes non-stop and I have no idea whether the pump has been primed. I cannot get the engine to start.

I tried re-tightening the vent plug to create suction as suggested and pumped like crazy and still nothing. (When the vent plug is tight, obviously no fuel can seep out the top to show that it's primed.)

I'm out of ideas and hope I don't have to call a mobile diesel mechanic out to help me start this thing.

Any other ideas?

 

[Robbbyr]

I'm back with the same problem, friends.

I have installed the new filter, filled the plastic container completely full of diesel fuel, and replaced it on the Detroit pump. It is the kind where the plastic container is on the bottom of the pump.

I have loosened the vent plug and pumped the silver pump for 10 minutes non-stop and I have no idea whether the pump has been primed. I cannot get the engine to start.

I tried re-tightening the vent plug to create suction as suggested and pumped like crazy and still nothing. (When the vent plug is tight, obviously no fuel can seep out the top to show that it's primed.)

I'm out of ideas and hope I don't have to call a mobile diesel mechanic out to help me start this thing.

Any other ideas?

Did you also change the engine-mounted secondary filter and fill it prior to installation?

I suppose you could try removing the vent plug and try filling it with clean fuel, then again use the primer pump and see if it will prime.

I have an older rig with a different primary filter assembly and I feel some resistance (indicating it is pumping) as soon as I begin depressing the bulb. Are you feeling like you are moving fuel at all? When mine is "full" I cannot depress my primer bulb at all, it becomes solid telling me it is full. But I then leave it alone for 10 minutes or so and it will again depress and pump more fuel in. Once firm again my engine will start right up.

 

[EGChester]

Did you also change the engine-mounted secondary filter and fill it prior to installation?

I suppose you could try removing the vent plug and try filling it with clean fuel, then again use the primer pump and see if it will prime.

I have an older rig with a different primary filter assembly and I feel some resistance (indicating it is pumping) as soon as I begin depressing the bulb. Are you feeling like you are moving fuel at all? When mine is "full" I cannot depress my primer bulb at all, it becomes solid telling me it is full. But I then leave it alone for 10 minutes or so and it will again depress and pump more fuel in. Once firm again my engine will start right up.

I will give that a shot, Robby!

 

[EGChester]

I have done mine several times. A few important things I’m not sure are in the other thread is when you go to drain the bowl, it can create a siphon effect and continue to drain and drain and never get empty. You need to crack open the vent plug on the top of the filter and this keeps it from siphoning from the tank. Use a piece of, I believe 3/8” hose to put on the drain to catch it in a jug and getting all over. You will need the wrench listed below to remove and install the bowl without damage. I fill the bowl with fresh diesel before installing as the primer is in a spot that gets tiring to pump up, it’s the silver button on top of the unit, pump it until diesel seeps out around the vent and then tighten vent.


https://www.amazon.com/dp/B00P3TLOH6?ref_=cm_sw_r_cp_ud_dp_FPZEHN7MZXKZG0B9F7NN

I have tried everything to prime the pump, Brian, but it's not working and my Seneca won't start now. I removed the vent plug and filled it with diesel, replaced the plug, and primed it with the solver pump for 5 minutes straight. Nothing. I have no idea what I'm doing wrong.
Any other ideas?
Eric - 303-810-3300

 

[Rustynuts]

I have tried everything to prime the pump, Brian, but it's not working and my Seneca won't start now. I removed the vent plug and filled it with diesel, replaced the plug, and primed it with the solver pump for 5 minutes straight. Nothing. I have no idea what I'm doing wrong.
Any other ideas?
Eric - 303-810-3300

The primer on mine never firms up to the point it can’t still be pressed, you just feel a slight resistance. Even primed the engine does not fire right up, it usually take 3-4 10-15 second cranks to start firing and then it some time stumbles a bit and I let it idle for about 10 minutes. Even the next sequential 2-3 starts after that take longer than normal unless you take it for a short drive.

 

[EGChester]

Got it!

Thanks Brian and others!

I followed all the helpful hints and got it to fire up.

I'm back in business and will hopefully meet up with you on the road!

Onward!

Eric

 

[Jmorenz]

The primer on mine never firms up to the point it can’t still be pressed, you just feel a slight resistance. Even primed the engine does not fire right up, it usually take 3-4 10-15 second cranks to start firing and then it some time stumbles a bit and I let it idle for about 10 minutes. Even the next sequential 2-3 starts after that take longer than normal unless you take it for a short drive.

Hiya,

I have a comment, which may or may not apply here. On my other diesel motorhomes, rear pushers, when the fuel filter is replaced, besides priming the filter, you have to run the “lift pump” by turning the ignition key from off to “wait” three times, then on the forth time you go from “wait” to fire the engine on…..

Would this not solve this issue?

Just asking….John

 

[Robbbyr]

Hiya,

I have a comment, which may or may not apply here. On my other diesel motorhomes, rear pushers, when the fuel filter is replaced, besides priming the filter, you have to run the “lift pump” by turning the ignition key from off to “wait” three times, then on the forth time you go from “wait” to fire the engine on…..

Would this not solve this issue?

Just asking….John

No lift pump on the ISB 6.7 as installed in our Senecas, direct draw from the tank (S2RV) or tanks (M2) through the primary fuel filter/water separator.

 

[Jmorenz]

No lift pump on the ISB 6.7 as installed in our Senecas, direct draw from the tank (S2RV) or tanks (M2) through the primary fuel filter/water separator.

Thanks, wasn’t sure it applied here or not. Not.

 

[PopBry]

Has anyone seen this?

My water separating filter has something that looks like Ramen Noodles in the bowl.

 

[Jmorenz]

That does not look good at all. Where is the filter itself? Or has it dissengrate? All is see is a black void? I would change that ASAP, it should not look like that. If the filter is in there, it’s awful black…

 

[Rustynuts]

When was the last time the filter was changed, it’s recommended to change it at ever oil change or annually.

 

[craigav]

My water separating filter has something that looks like Ramen Noodles in the bowl.

No that I have a diesel RV, I do have diesel trucks and some heavy equipment. What you are seeing is microbes, fungus, and/or bacteria that commonly grows in diesel and grows even better with a little moisture and light (such as the water catch bowl).

I would add a biocide to the fuel, drain the water bowl, replace the filter, and then keep an eye on it afterwards. ~CA



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