Air is being pumped into the secondary fuel filter which is causing the engine to die. Pressurized the fuel system and found no leaks. Any ideas?

 

Welcome to FTE, Rob.

I see you have an '04 F350. How many miles? Any modifications?

The more info you can give, the better

 

I think you got the answer to your problem on the other Ford truck forum.

 

ok i will check it out, thanks

 

Injector seal. Do the balloon test.

 

This is caused by a failed injector. Scuffed injector pintles sometimes seize or stick open allowing compression and combustion gasses to leak into the injector and back up into the fuel rail and eventually displace fuel in the secondary housing. Usually, cycling the ignition several times to recharge the fuel system will allow the engine to run and idle long enough to identify the cylinder bank where the injector is located. Many times I can even identify the cylinder number ...

Remove the secondary fuel filter cap, remove the element and fill the housing with fuel to just above the top of the standpipe (green o-ring) DO NOT START THE ENGINE. Locate the 14 gauge yellow/light blue wire at the left rear of the engine compartment. Disconnect the black in-line connector and momentarily jump the male connector that leads to the starter to the battery positive cable to crank the engine WITH THE KEY OFF. While cranking the engine observe the fuel filter housing for bubbles. If you see bubbles you have a faulty injector.

On really rare occasions an injector may loosen allowing combustion to leak past the copper injector seal and the lower fuel o-ring causing the same concern. I repeat, this is rare.

Other than this you won't be able to identify which injector has failed without a scan tool capable of performing a power balance test. When an injector fails in this manner a DTC may be set for the failed injector but because it displaces fuel in the fuel rail addition injectors will also misfire and usually set additional codes.

Good Luck!

 

I argue that you CAN identify which injector has failed. Read the BALLOON TEST link that I posted above. Been there, done that, and it worked like a charm. No scan tool needed.

However, I didn't realize that when an injector is letting air into the fuel rail, it has most likely failed internally instead of externally (failed exterior o-rings and/or a failed tip seal). Thanks!

 

I have checked for codes and there were none. Also found a lot of crud in the primary filter, checked the tank and it looks like the sides of the tank are rusting just above the fuel level, the float arm is even badly rusted.

 

I respectfully disagree with you... read my signature and then check the copyright at the bottom of the article.

It is impossible to identify the exact cylinder by using the balloon test. The test is only intended to identify the cylinder BANK that has the problem. From there you need to remove all of the injectors and inspect them.

Most techs no longer use the balloon test. At the time I wrote that article these issues were new to us. Many of us have determined that only severe combustion/compression leaks will be evident. There is not enough pressure or volume to even move the balloon surface or even actually inflate it. The pictures in the article depict an o-ring failure which is a major leak.

The newer technique (though not endorsed or recognized by Ford) is described in THIS ARTICLE showing screen shots from the diagnostic tester and, there is a video which stopped working when I moved the DTS site to a new server. I will try to fix that this weekend.

 

Is it possible that this condition can occur in a cold engine and then "go away" in a warmed to operating condition engine? It's hard to bubble test a fuel system with a regulated return without jumping through hoops, but I think by closing the return regulator I can "cap" the back end of the heads and force the bubbles out the front fuel lines. At any rate, I can, at least, add this to my diagnostic "bible" of driveway tools I can use to test my truck. Thanks for the good info Keith.

 

Typically rough running cold is an injector issue related to sludging. If your engine runs rough and smooths out when at operating temperature this is likely the case. To the best of my recollection I have not seen an engine with a stuck pintle "get better" as it warms up. They almost always come in on a hook but a few are driven in.

 

Sorry Doc, I must be losing my mind (4 kids will do that to a person). But I swear I remember doing the following routine to determine which injector was letting air into the system:

Disconnect the two effluent fuel lines from the secondary fuel filter housing.
Put a water balloon over the end of each line.
Pull all the glow plugs.
Unplug the fuel pump.
Install a glow plug in the first cylinder (don't plug it in) and turn the engine over.

If the balloon doesn't blow up at all, then move the glow plug to the next cylinder and do it again. The cylinders with a failed injector will inject some air into the balloon.

Yeah, when I did this it wasn't a lot of air that went into the balloon, but it was definitely noticeable when compared to turning the engine over on a cylinder with a good injector.

Did I dream all this?

 

It's not sludge, but I am having spool valve issues with one injector that's only been in 2 or so weeks. "Unfortuantely" the motor is clean enough to eat off of inside. It's not something I can pin down, but it's injector/fuel pressure related. I'm just asking questions before I start the bubble test just so I'll know everything that I can know. The bubble test is a relatively easy thing to perform so if I get a small leak from the right cylinder bank I'll know exactly where to go. I had the truck on IDS when my FICM crapped out. I knew I had one bad stick (#2 repeatedly) but I have another on IDS that comes and goes. When I get the known bad injector issue solved I'll go to the other. It's a work in progress--LOL.

 

I have kids myself. I totally understand.


I doubt you were dreaming. You were lucky to have been able to do that because in my experience the balloon almost never moves and it is largely considered unreliable. In theory it should work and I only say that because I myself have never had to resort to that procedure because I can use a scan tool to identify the cylinder(s) which is MUCH quicker than messing around with removing glow plugs. Aside from that, you can see small bubbles using the newer method that would never be detectable with the balloon test. For someone in your position I suppose it is your only option. Glad to hear that it worked for you.

It also shows that you are thinking!

 

Don't feel bad - some of this stuff still gives guys like myself that work with these engines every day a good challenge on occasion. Do you know what your fuel pressure is at WOT under load?