I remember who you are, and met you at the ultimate Ford Diesel dot com rally and KTP tour (and International Engine Tour) about a decade ago, and I even remember when you first picked up that F-550 of yours... because I have one too.
So, while you get mucho props for being old school around here... don't discount the guys who have posted responses to your problem. In this case, they have a very high probability of being correct.
You're going to need to drop your tank. Period.
Whether it completely fixes your problem or not, you're STILL going to have to drop it. Here's why:
1. You have an 550.
As do I. That means, unlike the pickups, we have a steel tank. Our tank is vulnerable to rust as well as delaminization of the aluminized coating applied to the tank to prevent rust. Search this forum as well as google independently for "f-550" "tank" "delamination." It is not very fun reading, but the "seems like it's running out of fuel" symptoms you have are the same symptoms that allowed hundreds of similarly situated Ford Cab Chassis owners to narrow down the cause to the tank. I read many posts on this site, and even MORE on other sites, and dropped my own fuel tank to have a look. While my tank was not delaminating, it did have something else...
2. You don't drive your 550.
Neither do I. Not much that is. I only have 49,xxx miles. Same deal, truck is for hauling loads, not getting groceries. That means, the truck sits for a week at a time (longer in my case, I'm not lucky enough to go camping every weekend). During that week, the corrosion flakes that are suspended in fuel have an opportunity to settle out, down to the bottom. While these flakes and granules sit there, undisturbed, they begin to stick to each other and to the bottom of the tank.
This is partly a good thing, because keeping these contaminates out of suspension and stuck in clusters keeps them out of the liquid fuel stream that is drawn into the pump. I found one such cluster, a 3/8" tall hill about 3 inches in diameter, situated directly beneath the black rubber pickup foot. It was a hardened mass that remained unmoved even after dumping the tank upside down, shaking it, and tapping on the bottom beneath it. A plastic scraper and a vacuum got the rust cluster out, and revealed that the steel beneath had pin hole pitted to half the depth of the thickness of the tank bottom.
I caught it just in time to be able to press fill these pinholes with a trowelled layer of an oil, gas, and diesel safe two part epoxy made for use in marine applications where removing the custom fuel tank might otherwise require cutting into the hull. I made test coupons of the cured epoxy and soaked them in diesel fuel for a week with no evidence of softening. These coupons are still soaking on my test bench. I had read about JB WELD softening when emmersed for prolong periods, so opted not to use that. I also obtained the MSDS's for seven other petroleum rated two part epoxy products, including the 3 different "fuel tank" repair epoxys offered by Permatex, and chose according to the researchable characteristics of the constituent active ingredients. I digressed.
3. You've tried everything else (fuel supply bowl related).
Can't say I did that, 'cause I didn't experience the symptoms you did. I didn't have any symptoms at all, other than the cold start idle lope, which is a universally common, coincidentally occurring issue that is entirely unrelated to your running out of fuel while driving down the road. You've been around long enough to remember that Ford put out a TSB back in 2000/1 regarding this cold start lope, saying that "Engineering is investigating". And by early 2002, Ford announced that the cold start lope is "a characteristic of the engine" and "no remedy exists or is recommended."
You might remember a Ford-Diesel dot com member that went by the name of "robyn", who put up a big long post about the cold idle lope back around that time. The lope is reduced in occurance by turning the key to ON and WAITING to start... not for the glow plugs, but for the electric fuel pump to stop running. And if the lope still happens, it can be immediately rectified by a sharp press down and release on the throttle... something you already do.
4. You like to maintain your truck.
As do I. Dropping the tank should be looked at as a maintenance issue, unfortunately. The nature of the beast for steel tanks like ours.
Entirely independent of the reasons other people drop their tanks, as shall be further described in the paragraphs to follow, WE need to drop OUR tanks because they are coated steel... they can rust, and in some cases can delaminate. While I did not experience the delamination, I did find the rust, and saved myself $800 in not having to buy a new tank. Had I not dropped the tank, the corrosion I did find would have eventually eaten through to produce a leak that would be UNSEEN due to the fuel tank shield covering the bottom of the tank.
The rest of this post is optional reading for you:
Most forum members drop their plastic tanks to do the Harpoon mod (unnecessary on the cab chassis tanks).
And the most often written about reason why forum members drop their tanks is to do the infamous Hutch mods, as outlined in the guzzler how to page linked by another poster in this thread. I'm not convinced. I wasn't back then, and I'm not now, especially after dropping my tank and finally handling these "mixing chamber" parts in the pickup assembly that people so casually toss away. I recall that Hutch lived in Augusta Georgia, so he may never have encountered a problem with fuel gelling on him. The parts he recommended tossing were designed to efficiently and dynamically reduce gelling risk by recirculating heated fuel with tank fuel, as explained in Ford's 1997 patent application below:
1. An in-tank diesel fuel recirculating manifold for recirculating warm diesel fuel from an engine through a fuel delivery system to reduce cold temperature clogging of the fuel delivery system, with said manifold comprising... (parts list edited out for brevity)... a temperature sensitive valve assembly disposed downstream of said fuel return inlet and upstream of said fuel return outlet and said fuel supply outlet for directing return fuel to one of said fuel supply outlet and said fuel return outlet, such that, at relatively cold operating temperatures, return fuel combines with supply fuel and is directed through said filter and out through said fuel supply outlet and, at relatively high fuel temperatures, return fuel is directed out through said fuel return outlet.
FIELD OF THE INVENTION
The present invention relates to temperature control in fuel delivery systems for an internal combustion engine, and, more particularly to temperature controlled recirculating manifolds for diesel fuel delivery systems.
BACKGROUND OF THE INVENTION
It is well known that when diesel fuel is at low temperatures approaching the cloud point, paraffin wax crystals will form. Further, at these cold temperatures, any water in the fuel tank may form ice crystals. To prevent wax or ice choking of the fuel system components, such as a filter, after a cold start, electric heaters are used in some prior art fuel delivery systems. Because newer diesel injection systems also have higher fuel supply and return flow for system cooling, the size of the electric heater becomes too large to have an adequate de-waxing or de-icing effect on the increased supply fuel flow. Therefore, it may be desirable to divert warm fuel from the injection system to the unfiltered side of the filter to de-wax or de-ice the filter after a cold start to unclog the filter and other fuel system components.
The inventors of the present invention have found that prior art temperature controlled recirculating systems, which are used to selectively divert warm fuel to the fuel filter to de-wax or de-ice the fuel filter during a cold start, generally do not adequately provide for de-waxing or de-icing close to the fuel inlet because these devices are located outside the fuel tank. This is primarily due to the fact that these devices are relatively large and would otherwise encompass too much space within the fuel tank. In addition, some of these devices do not adequately unclog the fuel filter because the recirculating devices are located remotely from the filter.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a novel in-tank diesel fuel recirculating manifold for recirculating warm diesel fuel from an engine through the fuel delivery system to reduce cold temperature clogging of the fuel delivery system. In one particular aspect of the invention, the manifold includes a housing, a fuel supply inlet disposed at one end of the housing and adapted to be positioned adjacent a bottom wall of a fuel tank, a fuel supply outlet disposed at another end of the housing, and a fuel return inlet and outlet formed on the housing. A fuel filter is disposed within the housing between the fuel supply inlet and the fuel supply outlet. The manifold also includes a temperature sensitive valve assembly disposed downstream of the fuel return inlet and upstream of the fuel return outlet and the fuel supply outlet for directing return fuel to either the fuel supply outlet or the fuel return outlet. Thus, at relatively cold operating temperatures, return fuel combines with supply fuel and is directed through the filter and out through the fuel return outlet. At relatively high fuel temperatures, return fuel is directed out through the fuel return outlet.
In a preferred embodiment, the manifold includes two longitudinally extending adjacently siamesed tubular filter housing portions for housing two longitudinally extending tubular filter elements.
An advantage of the present invention is that heated fuel is used to de-wax or de-ice the fuel filter, thereby obviating the need for electric or other external fuel heaters.
Another advantage of the present invention is that wax or ice build-up within the intake area of the fuel system is reduced.
Yet another advantage of the present invention is that a low cost, easily manufacturable fuel recirculating manifold is provided.
Still another advantage of the present invention is that a relatively large filtering capacity within a relatively small amount of space is provided.
Last edited by NYB; 09-26-2010 at 01:37 PM.