2003 Ford F350 - 6.0L Diesel Dies And Won't Restart; Fuel?

[Ruger77]

We have a 2003 F350 6.0 powerstroke (new engine and fuel filters by us 3,000 miles ago) in the shop that keeps getting air in the upper fuel filter housing. I don't have the adaptor to check pressure there so I'm checking it between the pump and upper filter and it is 55psi running, but it will stall after about 45 sec.

If you relieve the air from the top filter, it will restart and repeat the same. Pressure never drops. There is air in the return side at the fuel conditioning module(fuel is very foamy and gets worse right before it dies), so I suspected a leak on the suction side of the pump, but still have air even pulling fuel straight from pump out of jug (bypassing tank and suction lines). Found debris stuck to fuel heater in suction side of lower filter housing, inlet to filter almost totally plugged but filter very clean, cleaned debris out and replaced with updated fuel manifold (eliminates heater, mine was rotten). New filters didn't help. Still getting air.

I have found that with the pump on the bench and running, pumping fuel out of a container, there is 10 Hg of vacuum on the return ports on the manifold. This seems incorrect. So I looped the 2 return lines to each other: still getting some air, but not as much. With the return lines down in jugs of fuel, I still get foamy fuel. If I loop the 2 return lines together, I get less air, but still some. This thing has got to be sucking air from somewhere, but I cannot find a crack or bad seal.

Am I on a wild goose chase, or has anyone else seen anything like this? I have a lot more info if needed.

[steven kiser]

let's step back a bit here. if you take the pump and suck fuel out of a bucket and back into it and there is foam in the return flow the culprit has to be the pump. on rare and i mean rare occasions i've seen pumps suck air through the impeller seal. now if you hook up a new pump on a bench test and have no more air don't pat yourself on the back just yet. you have to make absolutely sure that there isn't a restriction on the system prior to the pump causing the pump to draw through the seal. if this is a dual tank and you're only testing pressure from one, the other may be contaminated. i've seen all sorts of weird buildup in dsl tanks. i wish the medium trucks came with drains in the bottom to drain off crapolla. if your luck this is a dump truck,if not, have fun dropping the tanks. there are lift pumps in the tanks. if one fails it could overload the pump on the rail. if you switch tanks with koeo and there is a noticeable flow change then you've identified the problem tank. just a suggestion here. if this turns out to be the issue you may want to suggest replacing both tank pumps.


on a separate point here, if there is a world pac close you can get o.e.m. pumps at a greater discount than the dealer.

[Tim Martin]

I think steve's suggestion with regards to the suspect being the pump is my thought. However, these vehicles have what is known as a horizontal fuel conditioning module on the left frame rail that the pump, water drain, and primary fuel filter are located in. These are known to be somewhat troublesome and can be replaced. As far as I know, there is no pump in the tank for the diesel unless someone put one there. Leaking connections, especially in the diesel with dual tanks can be difficult to locate.

[Ruger77]

Pump, filter, fuel conditioning module assy. on the bench, and 2 return ports looped back to each other, suction line in clean fuel and turn on pump and I get some air bubbles out of pressure line and pump sounds a little suspect (like it's trying to pump air sometimes). This truck is single tank, and I was getting air at the top filter even pulling fuel out of a jug while pump was on the truck.
As for the fuel conditioning module, I don't understand why the return ports on the fuel conditioning module would have / or need 10" vacuum on them. It appears that there is something wrong with the recirculating valve, causing the pump to try and pull fuel from the return side, but it sure looks ok. I have a new pump, cond. module, filter assy. on the way (cheaper as unit anyway), but I'm not convinced I understand how even a bad pump can create air and yet still pump 55psi. If I started crimping the return line I could get over 70psi. Thanks for all the help, I hope this isn't as frustrating to read as it is to try and explain! Profit for this job is probably over, so I would like to try and at least learn from it.

[Ruger77]

Update: New pump, lower filter, and conditioning module assy. (all 1 unit assembled from Ford). Still air at top filter.

[Tim Martin]

Whoa whoa here now. Might we got an injector that is letting compression up through it and into the fuel system? I have seen that already. After rereading this thread so far, I am wondering.

[Ruger77]

Wow.... had not thought of that. Ummm....ok now you got me thinkin.

[Ruger77]

This engine was replaced by us (Ford reman long block came w/ new injectors, oil pan etc.) 3 months and 3500 miles ago. Just for info. Ok, got truck running long enough to perform injector balance and found cyl's 1,3,5,7 not contributing as well as 2,4,6,8. Those cylinders (1,3,5,7) are all on the right bank on the diesels. This is starting to make sense that an injector is causing the air, disrupting the fuel in that bank.
Disconnected lines at upper filter housing from cylinder heads and confirmed that right bank is pumping compression into fuel, left bank is not.
Thanks Tim for the idea! I got too close to this one and it burnt me. The almost plugged fuel pump inlet totally threw me off. I'm still trying to confirm which cylinder has the bad injector, and how. Any thoughts? I was thinking of pulling the glow plugs 1 at a time and cranking. Also, could this even be a cracked head (unlikely but possible)? This is the second major problem with this engine since we installed. First problem was a broken high oil pressure fitting that connects the hose to the rail on top of the injectors on the same bank. We replaced the fitting 2100 miles ago under Ford warranty. Customer is growing less patient, as am I, with this engine. Jasper was $4000 more.... maybe it would have been worth it.

[steven kiser]

as far as a pump sucking air the issue of volume comes into play. you can have pressure galore but the volume being low because of a restriction will cause the air to be sucked by the seal. a bad injector allowing air is possible but that's a real long shot. bleeding the system with the quick response you're getting, in my opinion eliminated the injector. the issue of no code solidifies my injector thought.

[Tim Martin]

Usually the copper washer at the bottom of the injector can leak compression past or the injector pintle is not seating properly and compression is getting past there into the injector that way. Either way the compression is getting into the fuel system. This is a common problem on powerstroke engines. The fact that the engine was worked on recently helps to clue me in on where the issue may be. Not saying you did faulty work, but it can turn out that there is where the problem lies.

So far as $4000.00 more for the Jasper: I usually will not go less than a complete running engine n these because of all the potential issues I have to eat if we do an in house repair job. If this was a Jasper complete engine - ------- it would be their problem and you would be getting paid to do the job. I have to look out for my wallet. The customer doesn't do it for me.

[steven kiser]

i agree with a running complete from jasper. hope the issues with this engine ends here.

[Ruger77]

Yes it is the copper washer on #5 injector. I isolated it to the right bank last night, then started pulling glow plugs to relieve compression while cranking. Definetly coming from cyl. 5. Pulled injector and found copper washer shaped like a horseshoe and split. I may have not been clear earlier, but this was a Ford reman complete engine assy. replaced 3mo. and 3500 miles ago by us with a Ford 3yr 100,000 mile parts and labor warranty. They are paying the bill. The Jasper unit had the same warranty but included the turbo, that was the only difference. My earlier point was that maybe the Jasper unit would have been better assembled than the Ford unit. Customer is frustrated with 2 major problems so early after the replacement. My next concern is for the other cylinders.......do I recommend that we replace all the injectors and seals? I'm losing confidence in the quality of this engine.

[Tim Martin]

Well, in this case since there is some warranty involved, ya kinda are at the mercy of the warranty company. However, if the customer would be willing to assume the cost for replacing the others that might fly, although you'd want to run that by the warranty company.

Thanks for reporting your findings. And yes, I have seen this before where the copper washers were not installed correctly. .

[Ruger77]

Thanks for the help on this one. I thought using a Ford reman was a safe way to go, and so far they have been easy to deal with, but covered or not, customer needs his truck. We have used several of their 5.4L engines and several different Ford reman trannys with no problems, guess my luck just ran out.

[brianp87]

Pulling an engine out of an ambulance now for head gaskets yay 6.0L's .

[liljoe]

Pulling an engine out of an ambulance now for head gaskets yay 6.0L's .

Fixin to start on a 2000 ambulance 7.3 for the same job. Yeah, it's party time!!!!

[brianp87]

Rather do that then a 6.0L. Oh well pays the bills. btw on the 6.0L's I use these egr coolers and they work good.
http://www.bulletproofdiesel.com/

[Tim Martin]

Ah we make alot a money on either one of them. In one a the training classes I took on them a few years ago, the instructor from FOMOCO said that these engines (6.0L) were designed broke. I thought that rather bland.

[brianp87]

Ah we make alot a money on either one of them. In one a the training classes I took on them a few years ago, the instructor from FOMOCO said that these engines (6.0L) were designed broke. I thought that rather bland.

I might of had the same teacher cause I was told the same thing

[brianp87]

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