something just hit me, a vapor lock. air in the fuel line, expands when it warms, prevents fuel flow past point of bubble in line.
had a fuel line too near an exhaust pipe, kept heating the fuel and causing the vapor lock, moved fuel line to other side of frame rail and it was fixed.
also, if youhave an in-line elec fuel pump added outside of the tank, it is best place as clost to the tank as possible. fuel pumps push fuel better than they can pull fuel.
Actually, the problem is a bit more bizarre than I let on. Yes, we have had the fuel pump replaced "several times." Five in fact. We're currently negotiating with Ford's Motorhome Division customer service arm to see what we need to do to fix this problem.
Our opinion: it can't be the fuel pump.
The first fuel pump replacement was the redesigned unit from Ford. It lasted ~150 miles. Took it back to the independent shop, which claimed we must've gotten a bad unit from Ford. They installed a new pump free of charge, which made pump number two. That pump lasted about ~150 miles traveling though the heat of the Mojave desert in July. It took us 18 hours to go from Southern California to Prescott, Az. As we did not know the area, we took it to a Ford dealer. Diagnosis: fuel pump #3. The part was covered under warranty but the outrageous labor was not. We left Prescott heading for Cheyenne, Wyo when #3 went out 400 miles later, just past Albuquerque, NM. We limped to Santa Fe only to find all shops closed for the 4th of July (search for our post from last year if you're interested in THAT saga...). The next day we found out our 35' rig was too big for the local ford dealer so they subcontracted us to a local truck shop. Diagnosis: fuel pump #4. We raised all kinds of cain asking for explanations and were told, "the pump is bad. You want us to replace it or not?" We were stuck. Part was covered, but not labor. That pump lasted ~4000 miles and we thought all was well.
This year, we're heading back to Wyo when it starting bogging down again (Mojave in July). Diagnosis: pump #5 in Bullhead City, Az. "That's impossible," we stated. "If the pump is truly bad there must be something causing it to go bad. Find it and fix it." We asked them to check everything: cleanliness of tank, fuel lines, regulators . . the list goes on. "All is good," they say. What bunk. 1000 miles later, just north of Cheyenne, it happens again. This time we could turn the ignition off, then back on and continue on our way wih no futher problems (not so before). To be proactive, we had an independent shop in Cheyenne check everything out (again) and received a good bill of health. The "fuel pump waveform" I referenced before relates to voltage readings at the fuel pump itself. These measurements were taken to see if the fuel pump relay was acting up. Everything was within tolerances.
There is no rail pump, the fuel filter is clean, and the "turn it off, then back on" routine lasts until the next hill or so, or about a half hour, whichever comes first. We did this for 1100 miles from Cheyenne to SoCal.
When the motor bogs coming up to a grade (or sometimes on flat ground), the off-on routine completely clears the problem. We can continue up the entire grade while picking up speed - even 6% grades. It happens with full fuel, no fuel, night, or day. Some of you probably noticed I mentioned the Mojave desert in July - twice. I know there have been issues reported with fuel pumps and heat, but I refuse to believe the problem can't be fixed or there would be serious liablity lawsuits against Ford. Imagine a family stuck in the desert in 125 degree heat . . water runs out . . family in dire straights because they were never told not to drive their rig in the heat. I don't buy it.
I've turned to this forum to see if anyone has any ideas we could "float" to the next dealer. As we had to pay full price last time (get this, #5 was not covered because we were 30 days out from twelve months since the FIRST pump replacement), we're negotiating with Ford MH division to authorize our local dealer to find AND FIX the problem and provide refunds to boot. Wish us luck with that. I'm deathly afraid - but expecting - to hear the fuel pump is bad, again.
If it is, then what?
Our position is: we are paying these Ford dealers thousands (!) to replace fuel pumps. Either their pumps are junk (questionable, but we would hear a lot more of these types of stories if that were really true), or there is something causing our pumps to go bad. We've asked all the dealers to "find and fix" the problem, only to be told there is no problem other than a bad pump.
Could it be ECM? O2 sensors? Mass Air Flow? Who knows . . I'm not a mechanic. We just want the darn thing fixed. It's very frustrating to take off for a weekend or a family vacation only to be stranded with kids and dogs in a hotel for a few days while breaking out the wallet . . again.
Feel free to float "wild" theories. We'll take anything at this point.
I learned to hate my 98 F-53. It screwed up several vacations and Ford Truck Centers were the biggest rip-off pirates I have ever dealt with in my life. I switched to a DP.
I did the switching the ignition off while moving trick for 2500 miles one trip until I got home to have the pump replaced but after I replaced the pump that was that. My really good shade tree guy said that low fuel pressure, etc will cause the ECM to act up and cycling the power starts frsh. Maybe your ECM is bad or has marginal power? I still suggest having a fuel pressure guage hooked up and drive it until it acts up. Bad fuel line? Bad return line? I had recurring brake problems that were never resolved after thousands of dollars.
Trade it in!!! Get happy. I really shouldn't have bought the DP when I did but haven't looked back. It drives great, stops better, getting service work done is a joy.
We've thought about trading it, but we're weekend warriors with a typical two- or three-weeker in the summer. DPs, even used ones, are a bit out of reach for our current needs.
Other than this fuel pump thing, everything on the coach works great. Hate to throw out the baby with the bathwater. We'd like to keep it if we can, but this problem is driving us bonkers. Not good on the wallet either.
On some vehicles, the Engine Control Module allows the fuel pump to run when there's no sign of life from the engine (oil pressure, spark pulses, crank/cam rotation, varies with builder and engine). This provides fuel so you can start the engine! The Key Off/Key ON cycle will force the pump to run despite being flagged on oil pressure etc as noted above. If there's a false failure, like defective oil pressure sensor, pump will run till the ECM gets bad data again. That said, a friend added a chassis rail booster pump to his F53 and it solved his problems.
Possibility: Post this in Domestic Vehicles/Light Trucks at a batauto.com and see if some of their sharp guys has a tip.
since it is out of warranty, add a generic fuel pump to the line near the tank as a test to override the Ford pump.
Might save you from switching on/off or may just cost you $30 and a few hours.
ps...your local ombudsman/consumer advocate/Clark Howard would bulldog this issue for you. They should NOT have been charging labor for warranty repairs.
After reading the rest of your story, you are more than likely right, it is not the fuel pump. You are the victim of "easy way out" diagnosis by various so called technicians. Numerous sensors feed information to the ECM, add to that the connectors and the wires to those sensors and you have a problem. One bad signal, and the ECM will go into what Ford calls politely "limp in mode". A bad sensor, most times can be found, a loose connector or bad wires on the otherhand are a different story. If it doesn't occur in the shop, it can be next to impossible to find and hence the infamous "easy way out" diagnosis. I personally would check every connector and their respective wiring harnesses in and around the engine for any signs of stress caused by heat or rubbing. Replacement of another pump is not an option, it clearly is not the cause of your problem.
I was looking through my 1999 Ford manual under "Driveability Problems" when I came across this note:
"NOTE:
For applications with linear knock sensor, a lack of power may result when the vehicle is operated with a breakout box installed at the PCM. The KS circuits are not shielded in the breakout box, and KS signal noise may be noticed by the PCM. If this happens, spark timing will be retarded and a lack of power may result."
While I doubt you're driving around with a breakout box attached to the PCM it did suggest your problem might be caused by the electronics rather than fuel.
It's been so long since I've worked on a 460 I don't even remember if they have a knock sensor. Regardless the note mentions that a "loss of power" could be due to the PCM retarding the timing. It could be from sensor errors, bad PCM, or interference from improperly shielded wiring harnesses.
At least it's another direction to look, and yours is obviously not the first Ford product to suffer from a lack of power drivability problem.
have you checked your fuel cap? maybe not venting properly.causing a vacuum in the tank and holding back the fuel.
does the engine light come on.?
any codes?
is this fuel injected multi port or throttle body?
had injectors on a ford ranger 2.9 plugged on time,that thing would not pull the sheets of a bed.Had the injector cleaned and wow truck almost scared the s out of me.
Factory F-53 fuel cap was installed during pump #5. We thought, "why not? Can't hurt." No change. We thought about injectors too, but if they were clogged we couldn't gain speed on a grade after off/on, right?
I'm pretty convinced it's electronics. I failed to mention that *sometimes* (not always) it will bog immediately if I take overdrive off.
Our current predicament boils down to who is going to pay for the next round of diagnosis. We've asked Ford MH to authorize our local Ford dealer to find and fix the issue whether it's a fuel pump or not (which I think we all agree, it's not). If we have problems with that avenue, we'll take it to our local mechanic and gear up for a big fight with Ford. We won't take this laying down. As topflight51 said, I think we're victims of "it's got to be the fuel pump" diagnosis, which is really frustrating considering we've explained the entire history to every dealer.
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You are the victim of "easy way out" diagnosis by various so called technicians. Numerous sensors feed information to the ECM, add to that the connectors and the wires to those sensors and you have a problem. One bad signal, and the ECM will go into what Ford calls politely "limp in mode". A bad sensor, most times can be found, a loose connector or bad wires on the otherhand are a different story. If it doesn't occur in the shop, it can be next to impossible to find and hence the infamous "easy way out" diagnosis. I personally would check every connector and their respective wiring harnesses in and around the engine for any signs of stress caused by heat or rubbing. Replacement of another pump is not an option, it clearly is not the cause of your problem.
