Isata 5 - Cummins 6.7 changed fuel filters. now it won't start

[chaps2018]

Thanks for the update and here's to safe, productive travels![emoji106]

[Delco Bobby]

I am glad you got it running. Have a good trip and please post updates.

[BigLou80]

You need to bleed the system. Somewhere on there post filter there should be some.sort of bleeder to let the air out. Open that and let the pump run in the on but not running position until you get fuel and not air.

I'd highly advise against filling the filter with fuel ahead of time, that will allow unfiltered fuel on to the injectors.

[BigLou80]

Also its peobably a water separator followed by a filter its not two filters. I'm not sure of the specifics but thats my guess

[DieselDrax]

Originally Posted by BigLou80

You need to bleed the system. Somewhere on there post filter there should be some.sort of bleeder to let the air out. Open that and let the pump run in the on but not running position until you get fuel and not air.



I'd highly advise against filling the filter with fuel ahead of time, that will allow unfiltered fuel on to the injectors.

I’m guessing you haven’t read this thread completely before replying. The lift pump is not working which is why the OP was unable to get the system primed after replacing the filters.

[jtesta1]

Most engine manufacturers run two fuel filters. When you get filters changed they always fill filters with fuel to keep the fuel system from loosing its prime. Whenever you stop for fuel open the filter petcock into a container to drain any collected water out.dont empty filter just a few drops till water stops. If you're afraid of a little dirty fuel going into your filters you can fill them with transmission fluid, it cleans injectors while keeping prime.

[Lighting546]

There should be an emergency pump shutoff in the coach, it's usually on the passenger side. You may have inadvertently tripped it and need to manually reset it, if it trips the fuel pump will not work until it's reset. You could relate it to a "circuit breaker" in your homes breaker box, when the breaker trips you don't have power and you have to go to the box and reset it to turn the power back on.

When fuel filters are changed you're supposed to fill the new filters with fuel before installing them, if you don't then the fuel system gets "air bound",which means there's too much air pressure in the system for the fuel pump to overcome, which may have tripped the pump shutoff safety switch or the fuse for the fuel pump could have blown.

The first time I changed the fuel filters on one of my Peterbilts I didn't even think about filling the new ones with fuel before installing them and wound up with an air bound fuel system that took what seemed like forever to fix. After that fiasco I never again changed those filters myself, I took it to one of the truck stop repair shops and let them deal with it.
I hope you get your issue figured out and fixed soon.

[Lighting546]

Originally Posted by jtesta1

Most engine manufacturers run two fuel filters. When you get filters changed they always fill filters with fuel to keep the fuel system from loosing its prime. Whenever you stop for fuel open the filter petcock into a container to drain any collected water out.dont empty filter just a few drops till water stops. If you're afraid of a little dirty fuel going into your filters you can fill them with transmission fluid, it cleans injectors while keeping prime.

That's the fuel/water separator, and there are two kinds; manual or automatic. If you have an automatic one you don't have to do a thing, it automatically drains itself. If you have a manual one then you have to manually drain the water on a regular basis, and that information should be in the owners manual.
The book for the one in my Ford truck says to drain it once every 30 days. I never had to worry about draining the one in my Pete as they did it automatically. I guess if you're spending upwards of $160,000 on a truck you should get a lot more bells & whistles than you get when you buy a 4 wheeler (a car or pickup).

[Rick_Geneseo]

You have an airlock. Make sure the fuel filters are full then bleed the air out of the lines.

[gberge]

You guys are over complicating everything. You can replace both the fuel filter(under hood) and separator (frame mount) dry and prime. Even if you have only one combo filter/separator (under hood) you need to cycle the key multiple times. With the door closed, rotate the key to on/run not start, and the lift pump will run. Turn the key off and open the door to reset the dash program. Then cycle key and door again. This also applies to push button ignition by looking at the lighted ring around the button for position. After cycling the lift pump several times, crank the starter for no longer than 20 seconds. If it starts let it run for several minutes. If it did not, cycle the lift pump again while letting the starter cool for a minute or two. Then start and run. If you don't let her run long enough after priming it may crank for a bit the next start, but will self prim just fine. You can prefill the filters, but it will not magically be primed. You will still have to cycle the lift pump.

[Bill Davis]

I don’t get all the new post. He solved his problem a couple days ago.

[DieselDrax]

Originally Posted by Rick_Geneseo

You have an airlock. Make sure the fuel filters are full then bleed the air out of the lines.

Originally Posted by gberge

You guys are over complicating everything. You can replace both the fuel filter(under hood) and separator (frame mount) dry and prime. Even if you have only one combo filter/separator (under hood) you need to cycle the key multiple times. With the door closed, rotate the key to on/run not start, and the lift pump will run. Turn the key off and open the door to reset the dash program. Then cycle key and door again. This also applies to push button ignition by looking at the lighted ring around the button for position. After cycling the lift pump several times, crank the starter for no longer than 20 seconds. If it starts let it run for several minutes. If it did not, cycle the lift pump again while letting the starter cool for a minute or two. Then start and run. If you don't let her run long enough after priming it may crank for a bit the next start, but will self prim just fine. You can prefill the filters, but it will not magically be primed. You will still have to cycle the lift pump.

Please guys, read the entire thread before posting. The OP has a lift pump that is INOP. That is why it was failing to re-prime.

Always a good idea to read a thread completely before replying to ensure you don't make wrong assumptions to try and provide help that really isn't help.

[daveinthekeys]

I have now driven 500 miles and no symptoms of any fuel starvation issue. I assume that lift pump has been dead for some time. I wonder how long?

I also know that opening the truck door has nothing to do with it. By testing the fuse to the lift pump, I know that the lift pump goes on for 4 seconds every time the key is turned on even with the door remaining closed or having never been closed. That fuse is also powered 100% of the time the starter is engaged.

I also think, that even without a lift pump. Had I filled the filters with fuel. It might have primed itself. If I had not first burned up all the fuel that was left in the high pressure pump and injectors. I do not know this. But I do know that without any fuel in those areas. There is no way that I could prime this system. Meaning the high pressure pump itself needs to be primed in my opinion. If that pump is empty of fuel it will not draw the fuel from the filters and lines that are full of fuel to itself. I tried this too many times to believe it. I think people are getting idea that this works based on gravity pushing fuel to the high pressure pump. Or by forgetting that I had already ran the entire system out of fuel. The trucks high pressure pump is the higher than the filters. Which is why Ram installed a lift pump. (Duramax, for one, is using a push bulb and has the same high pressure pump.) My boats do not need a lift pump because the fuel tanks are higher than the high pressure pump and all the filters.

In my case, I replaced the filters and did not fill them as per the instructions in the user guide (p164) that came with my Ram 5500. I cycled the key six times before I started just to be sure, even though the book said four was good enough. It then ran for about 20 seconds. Probably enough to empty the high pressure pump and the injectors. My thought is that perhaps, if I had known that my lift pump was not working. I could have screwed on the on-chassis filter. Inserted the on-engine filter. Filled the on-engine filter, which also fills the on-chassis filter and the line between the two. (gravity does this) It is possible that in the 20 seconds that the engine ran. That it would have primed the entire system. Which is why so many people suggested that I simply fill the filters and start it up. Again, I had already disabled the high pressure pump's ability to draw fuel to itself by running it dry.

The paranoia is that the dead pump is somehow restricting the ability of the high pressure pump to draw fuel from the tank. It might be. And it might have been doing this for a long time (or not). I have seen no loss of power, or any symptoms before or after this saga.

So the lesson here is that before you change your filters. Make certain that your lift pump runs. This can be determined by getting under the truck next to the tank. Or possibly by listening through the fuel fill opening. I know that for my gas powered Ram1500 of the same year. I can hear that pump just standing next to the truck.

Thanks again for any and all advice. Yes, some was more on track than others. But the fact that people volunteered is all that matters to me. Though I will have to admit that comments of "why did you try to change your own filters" and "why don't you just put in a new pump" were somewhat demoralizing. I changed the filters because nobody else will do it near where I live. Also, it is a very simple job. The fact that nobody was going to help remove my fuel tank and install a new pump laying on the ground in the dirt in my yard was just rubbing salt into the wound when people said, why does he not just call the mechanic to get it fixed.

I will post again with how it gets/got fixed. I am leaning toward installing an external pump and thus insuring that I will never be forced to remove the fuel tank in my yard. Yes, that would not be under warranty. However, almost any RV dealership could do this job easily and thus preclude my search for a Ram dealer that will do it. And also, if it broke in less than 15,000 miles. Do I even want another factory pump?