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

[vineyardmh]

I would suggest you check Dodge & Cummins forums also. There, you will more likely find others who might have had the same problem - you might find posts that explain how to resolve it. (AND - you should provide the year for your Cummins. The 6.7L has 2 different 'versions' - and the solution MIGHT be different.

I have a 5.9L Cummins - and when changing filters - you have to get air out of the system BEFORE the injector pump - and if not done properly, the you have to get air out of the injection pump system (which is a PITA). BUT - for Common Rail systems - you have to ensure that the lift pump - which might be delivering fuel at 50 -70 psi to the 'common rail' is vented. You might have to 'crack open' a fitting where the fuel goes to the 'rail' (on the head) - and then try to turn the engine over until fuel starts leaking around the fitting - and then you tighten up the fitting.

One good forum: Dodge Cummins Diesel Forum
Also - look for 'Diesel Bombers' - (they have all major trucks - Dodge, Ford, Chevy....and then there are sub-forums to cover specific 'lines' or models...)

Good luck.

Originally Posted by daveinthekeys

Some Current Ram diesels, including mine, have "TIP" start.

We turn the key to the crank position then let it go and the engine will continue to crank over until it starts, or until you turn off the key.

Without Tipstart, you would have to hold the key in the crank position until it started then let it go.

[daveinthekeys]

I do not understand how the pump can be airlocked when it is submersed in diesel fuel in an almost full fuel tank? Unless you are referring to the high pressure pump on the engine?

The engine has started for 10 - 15 seconds three times. This would have done the same as starting fluid in the air intake and released any airlock on the high pressure pump? If that is what you are referring to? I am not trying to be difficult. I really do want to know.

Why does the fuel filter canister not fill with fuel on its own when I turn the key? I have left the cover loose on the on-engine one to see if it would spill out but get no fuel. The on-chassis filter does not get fuel either. I have turned the key enough times to fill it. But when I remove it. It is empty.

Currently both filter have fuel because I manually put it in there. I have yet to see the pump in the fuel tank do anything since I changed the two filters.

[Whalenss]

Did you recheck the plug in wire connection on the first ( frame ) filter?

If fuses good, then the pcm is not getting the correct signal to activate the fuel pump.

[daveinthekeys]

I did check the plug in wire on the on-frame filter. In fact I had removed and reinstalled that filter several times now.

It is conceivable that there is some diesel fuel in that socket though. I could try and clean it? Since I first loosen the wire and then drained the fuel it did get wet.

[vineyardmh]

Put the year of your truck in the thread. Important.

If you have air in the system - and the system is sealed - the air compresses - you have a small high pressure bubble in the system - but that bubble keeps the fuel from getting where it needs to go. That is why 'cracking' fittings and lines and trying to run the engine might help - the air gets pushed out...and then fuel leaks out - and then you tighten the fitting.

YES - your in-tank fuel pump is not having problems getting fuel and pressurizing the system in front of the pump. BUT- if there is air in the front system, the air needs to be 'bled out'.

[I had an older Chevy diesel - and I attached a vacuum pump to the mechanical injector pump - and sucked the air out until fuel started coming out...and this 're-primed' the system. Without doing this - it was almost impossible to start.]

Originally Posted by daveinthekeys

I do not understand how the pump can be airlocked when it is submersed in diesel fuel in an almost full fuel tank? Unless you are referring to the high pressure pump on the engine?

The engine has started for 10 - 15 seconds three times. This would have done the same as starting fluid in the air intake and released any airlock on the high pressure pump? If that is what you are referring to? I am not trying to be difficult. I really do want to know.

Why does the fuel filter canister not fill with fuel on its own when I turn the key? I have left the cover loose on the on-engine one to see if it would spill out but get no fuel. The on-chassis filter does not get fuel either. I have turned the key enough times to fill it. But when I remove it. It is empty.

Currently both filter have fuel because I manually put it in there. I have yet to see the pump in the fuel tank do anything since I changed the two filters.

[daveinthekeys]

the system was not sealed at all times as I tried to run the pump (by turning the key) with the on-engine filter cover off as a test. The canister did not fill up. And the rear on-frame filter has never gotten any fuel from the in tank pump either.

I don't think we have even gotten to the probable air inside the injection system yet. Though from what I read it should bleed itself as the electric in fuel tank pump is supposedly capable of doing that after the truck has run out of fuel.

The manual says cycle the key a few times and the system will be primed. I would have to assume that after some key cycles either or both of the fuel canisters should have some fuel in them. If that pump was working.

I do not believe the lift pump is pumping.

I am going out to clean off the terminals on the on-chassis filter next.

This is a 2016 6.7 Cummins diesel.

[vineyardmh]

A question/a thought....

From your writing - it sounds like the system is OPEN...filter cover not installed....which has me wondering if there might be 'safeties' that turn the fuel pump off if there is 'zero resistance' (....consider a truck gets in a crash and the fuel line is ruptured....does the fuel pump keep pumping fuel to feed the fire?) What if there are safeties? Maybe button the system EXCEPT for a slight loosening of a fitting of a fuel line to the common rail....

Again - google search 'my 2016 Dodge cummins won't start after fuel filter change' - and see what comes up.

[Whalenss]

The u

[daveinthekeys]

I have tried it both open and closed. My most recent experiment was to clean the contacts on the water sensor plug on the on-chasis filter as it did get wet from diesel fuel.

I agree that having the system open is a risk. However, I do think that the main fuel pump in the tank would to know the difference for at least a few moments. None-the-less I have tried it many times both ways. In no instance has any fuel been moved from the fuel tank to any fuel filter.

With the system closed, and after 8 key cycles per the manual instructions (which suggests needed fewer), I cranked the motor for three 10 second attempts.

Now I am quitting until tomorrow.

[chaps2018]

While I do not have an ISATA, I do have a 2016 Cummins 6.7L and have changed filters several times. I follow the procedure in the shop manual. (ie, no prefilling). A couple of comments after following the thread.

-I found out by accident that the fuel pump will continue to send fuel if the engine mounted filter petcock is open.
-Not sure if you have tip start, but the procedure for priming is to turn the key to the ON position (not start) 3-4 times pausing at the ON position to let the pump cycle (ie, you should hear the pump run for about 15 sec with dry filters).
-My canister lid is real tricky to get on straight. Assuming you have the new lubed O ring on the lid as well.

The latest thinking is the pump is not running. As mentioned--either a massively open situation (zero force sensed by the pump) or a dirty connector on the frame mounted electrical connector. (I have read about both of these being a likely cause of no-start after a filter change).

Hard to believe the fuel pump is bad but rather something is telling it to shut off or not start at all.

Good luck and keep us posted.

[Orangecrush]

Originally Posted by Brewhedd

I wouldn't be disconnecting fuel lines and injectors. I don't get how you can't crank the engine for a second and then return the key to the "on" position. Every vehicle I've ever owned will allow you to do this. The problem is all the air needs to be bled out of the fuel system. Personally, I decided when I bought my new Duramax that I wasn't going to do something even as simple as changing the oil. These motors are just too expensive and I don't want a warranty claim denied if something happens. The dealer will be changing the fuel filter also. I don't want a problem, like the dealer claiming the fuel system was damaged when I changed the filter. Just not worth it over a hundred or so bucks.

I'm with you... I'm not as concerned as voiding a warranty as I am wasting all the time the OP has spent trying to figure this out. The worst part is if he can't figure it out, he'll pay the dealership or a mobile company more than what it would have cost to just have the work done.

No disrespect meant to the OP but at 55 years old and turning wrenches as long as I have, this cluster fudge is EXACTLY what I try to avoid. I'm sure it's something simple and hope you get it fixed soon but IMO, the headache simply isn't worth it.

Hope it gets fixed soon.

Mark

[CHICKDOE]

this is just a guess. i have a 6.7 cummins. you say you think the fuel pump is not pumping. others say something is probably telling it to not pump. these things are computer controlled to the hilt. i'm not walking out to the truck. i know there is a display screen with oil life and i think there is one with fuel filter life. could it be as simple as telling the computer to reset the fuel filter life and that is what is telling the pump not to pump?

[vmfa]

Originally Posted by caseymyers

I have a 3500 RAM and my limited knowledge is that you have to 'prime' the filters. They have to be full of fuel when you put them back together. Other wise the engine will not get fuel. Hope this helps.

Did you put fuel in the filters before you screwed them back on?

Gas cars push fuel through the filter whereas diesels suck the fuel through


The filters so if you didn't fill the filters with diesel fuel before you put them back on the only thing it's sucking is air and diesel pumps can't suck air so cannot pull fuel from the tank through the filters.

[vineyardmh]

Dodge Cummins have a lift pump that pushes fuel through filters. The OP's 2016 has a pump in the tank that pushes fuel.
His problem appears that the pump is not turning on - for one reason or another.

IF the pump is turning on - fuel might not get through the filters and to the Common Rail - if it is 'airbound' - and one needs to vent off the air to permit proper fuel delivery to the rail.

Originally Posted by vmfa

Did you put fuel in the filters before you screwed them back on?

Gas cars push fuel through the filter whereas diesels suck the fuel through


The filters so if you didn't fill the filters with diesel fuel before you put them back on the only thing it's sucking is air and diesel pumps can't suck air so cannot pull fuel from the tank through the filters.

[cariboo camper]

Daveinthekeys: Get a can of "ether" (engine start or cold start) When your engine is running, assuming you can get it to run for a few seconds, stand by the air filter intake with the air filter removed so spray from ether start goes directly to engine and continuously spray ether, in short bursts, into the air intake, every time you give it a shot of ether the engine will rev up, back off the ether, engine rpm goes down give it another shot. This may draw the air out, which I am sure is your problem. If engine will not start as you said it did a few times try giving it a few shots of ether during the cranking process. If during this process the engine starts knocking, stop!

This is a situation I have run into many times with newer engines in logging equipment after oil changes, filter changes etc. Has to be the computer in these newer engines. Some will say the ether dries the cylinders out and causes other problems, sure! if used too much, but for what you need to do, not really an issue.

OK having said this and you are living in the Florida Keys, good luck in finding cold start fluid (ether). I live in a way colder climate than you and it is readily available in cold winter temps. Hope you find a solution.

[daveinthekeys]

For those of you who have dealers within a reasonable distance. I have no issue with using them. However, in my case, I live in the middle of the Florida Keys. We do not have those kind of services.

Also, changing fuel filters is nothing like rocket science. I have done it many times on many vehicles. For this particular job it was not about saving money. It was about not driving 4.5 hrs each way to get this job done. I will also say that having some ability to get oneself out of trouble has paid off in the past and each mechanical job learned helps with the next one for myself, or others that need help.

Meanwhile is "dirty connector on the frame mounted electrical connector" the connector for the water sensor on the on-chassis filter? Or is this something else. The underside of my coach is very clean btw. But I do live in a salty environment and a dirty contact could occur at anytime. However, it would be a real coincidence for it to occur exactly at the moment of the filter changes. If this frame mounted connector is not the water sensor on the on-chassis filter. Please help me find it.

By putting a volt meter into the pump fuse I can say for certain that the circuit for the pump receives power for four seconds when the key is put in the on position. When the engine is being cranked that circuit receives power continuously. When the key is moved back (I have a "TIP" ignition) the circuit power is stopped.

The user guide, that came with the truck, provides the instructions for changing these filters. It reads that after changing the filters, do not refill them and check to simply start the truck and check for leaks (page 162). Thus one can assume that the pump in the fuel tank (lift pump) would fill these filter canisters easily, air in the system or not? I have read the directions that came with the filters which do say to turn the key on for four seconds four times then start the truck. This makes perfect sense. And I have also tried that many times.

I did reset the fuel filter indicator.

I am not sure about the "massively open, zero force" thinking as apparently the pump is thought to be ready to pump into empty filters and also after one runs out of fuel. I do have a portable diesel fuel polishing system that I use on my boats. Thus I could suck or push fuel into the lines to test that idea.

While I did purchase OEM filters. It is conceivable that the do not run feature has seen one of them as off spec. I am going to purchase new ones today. If I can get them. I doubt this is the solution but short of replacing the lift pump..any port in the storm.

I have read that it is possible for somebody to have a bad lift pump and never know it until they change out the filters and have my situation. Apparently the pump on the engine can suck the fuel from the tank on its own in a perfectly primed system. This is not good for the pump or engine as the low flow of fuel does not contribute to any cooling affect for the engine.

What if our extremely long run of relatively narrow fuel lines has pushed the OEM pump beyond its limits? Consider the distance from my 36 foot motor homes fuel tank location compared to a normal sized truck.

While I am not excited about dropping the fuel tank and replacing that pump. I think that I am getting closer to that. Does putting 12 volts into the fuse box and getting no pumping bypass "do no not run with no or wrong filter", "massively open". "air lock" possibilities. If this does not do that, can anybody think of another way to force this pump to move. So that I can know that it is not the pump itself. I have been under there with a friend turning the key and hear nothing. I see now way to get to the pump wiring as it is apparently on top of the tank.

[CHICKDOE]

sorry for all the problems you are having. everything you say does seem to be pointing to the fuel pump not pumping fuel. you've proven you have voltage at the fuse. now why is it either not getting to the pump or the pump not running? i guess i'd try to trace the pump electrical leads to see if you can find a loose connection as they go to the pump. obviously if you have to pull the fuel tank to get to the pump you will look at the connections and test the pump once you can get to it. you have power at the fuse yet the pump does not run. what else can you do? again really sorry. could this be a coincidence that hits at the wrong time and throws your thoughts off track? looks like it.

[chaps2018]

Dumb question--there is fuel in the tank?

Rig is level enough? (if the fuel tank is near empty)

While I am on a "dumb question" roll...did u check for error codes? (Code reader available at auto parts store, Walmart or overnight via Amazon) $30-50ish

[mwdilday]

In my limited experience the injectors may need to be bled after running out of fuel. I know nothing about your specific engine.

[daveinthekeys]

I tried a test today using my 2016 gas powered Ram 1500 truck. The fuse box looks identical to the Ram 5500 fuse boxed on my not wanting to start after the fuel filter change engine (both 2016 Ram).

On my gas powered truck I can easily power the fuel pump by putting 12 volts into the fuse holder. I can hear the pump and see the spark from the sudden current draw on the battery terminal. When do the same thing on my disabled diesel truck the pump does not turn on.

I wonder if the PCM is before this fuse. My guess is that it is. If that is the case does not this prove that the pump is bad. Yes, it could be true that some wire came loose at exactly the same time as my filter change. But it is more likely that it did not. I am unable to trace the wires from the pump as they are hidden in a bundle above the fuel tank and out of reach and sight.

I have read that these engines will run without a lift pump if primed and that sometimes people do not know that they have a bad lift pump until the change the filters. Does anybody agree with that? Could I have had a bad lift pump before I changed out the filters even though it ran fine. I will say that I never push the motorhome hard. So it never gets to a point where I am accelerating heavy or forcing it up a hill. Fuel flow was thus never given much effort.

If I do decide to remove the tank and pump. Is there a way to drain the tank? I do not see a petcock. Could I suck out the fuel from the fuel line at the on-chasis filter using my portable diesel fuel polishing system. Could I hook up the fuel polishing system to that line after the on-chassis filter to pressurize up to the on-engine filter as a final test that there is perhaps nothing wrong at the engine or PCM?

I am reluctant to squirt ether or WD-40 into the air intake to make it run. Though I believe it would run. As it has run for a few moments over the past few days. Presumably from the injector pump sucking fuel.

I think for all the time that I have put into this I could have dropped that tank and put in a new pump by now.