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He's a 2000 F350 7.3 6 spd 4x4 dually. It all started 3 weeks ago when he stalled going 80 down the highway and we've been stranded on this mountain since. The chain of events are in order as follows; replaced fuel filter clogged on highway, replaced fuel pump, stalled coming home from town again(same location as previous) took the new fuel filter out he got us home. Dropped the fuel tank pulled sending unit and the boot w/screen disintegrated, replaced it cleaned the plastic tank put it back together test drove 2 miles ran very well til then starved for fuel again lost power stalled, opened the cap on housing pressurized air came out tightened up he cranked up nice sounded good til we got to the end of the driveway, same routine. since there was trash in the tank we replaced the fuel pump and filter again and put a gasket kit on the housing...same issue. Pulled a vacuum on suction side of the it held at 1". He only pulled engine warning light when the ICP was pulled to test, put it back in. Checked UVC connections....WHERE IN HELL IS THE AIR COMING FROM?
Replaced CPS no fix,
How were the screens on the in tank fuel intake? You didn't mention anything about them. What's your fuel level? I can think of two places that air could get in but there might be more. 1) If the steel tube in the tank has rusted through up high in the tank. 2) The quick disconnect fuel lines could have deteriorated O-rings in them letting air in.
Did you remove the plastic cartridges? They get plugged, too. It's usually best to remove most of that- see the link above.
In addition, the lines from the tank to the intake side of the pump have quick disconnect fittings that fatigue and leak with age, so most of us replace the line from the tank to the fuel pump under the driver's seat area with 30r9 or similar diesel rated, injector hose and use double injector hose clamps (don't bit into the line)
How full is your fuel tank?
The second most likely scenario is in your fuel bowl itself.
You might have a significant leak in one of them- suspect the drain valve, which can allow air to leak back into the bowl when you turn off the truck/fuel pump.
If the fuel return line from the bowl to the tank is restricted or plugged, it can cause problems, too.
Back to the bowl.
Debris in the bottom? Did you remove the heating element and center post and suck it all out?
Use a screwdriver or something and make sure you can push down on the center post's valve on the top center of the post. It should have spring resistance but not be sticky (debris in there would be a problem)
What filters are you using? Can you post a pic of a "clogged" filter? Is it black? Is it slimy?
Are you sure you are getting the filter seated all the way? New cap gasket and facing the right direction?
A bad CPS can mimic a fuel problem. Stalls, you mess with fuel filter or whatever, put it back and it runs for a while. You think you got it, but then it happens again and your filter looks fine.
Contact Clay at RIFFRAFF FORD DIESEL PERFORMANCE PARTS for CPS. They are very important and lots of bad info/versions floating around. He will take care of you.
What is your oil type and level on the stick? How old is your oil and filter?
Remember, the injectors are driven by oil, so any anomolies there will act just like fuel.
There are more things to check if none of these are it, but these are the first and main things to try. Once they are taken care of, you can test your ICP, IPR, UVCH if needed.
pulled and cleaned fuel tank replaced complete sending unit and all screens are new. took line off sending unit at tank on suction side and plugged and pulled vacum from suction side of pump vacum held at 19in for 30 min so its not leaking. hook sending unit up at tank and put tee in line at suction side of pump and put vacum gauge on tee with a new fuel pump with pump on got a reading of 0-1 in on guage of vacum within spec i was told. changed cps and checked uvc connections. truck has a lot of pressure in filter housing every time every time it acts up. i take filter cap loose and fuel and air sprays out. i cycle key and cand see air bubbles in fuel when its filling bowl then it clears up,i reinstall filter and it runs fine for two miles then same issue. should i pressure return line to tank to make sure its not clogged up. i dont want to damage new sending unit. i put new o ring kit in filter housing and cleaned housing in carb vat and blew air through all connections. i unpluggeg ipc and it threw service engine light and throttle was sluggish so i plugged it back in and it went back to normal and light went off so i guess its ok. this thing is really kikn my butt.
I would try a fuel flow test. Turn the little yellow lever on fuel bowl.
Turn on the ignition and collect the fuel out the drain. The pump will run a few sec each time the ignition is cycled. Do you get a good stream while the pump is running? Can you here it running?
Full-blown Hutch and Harpoon mod - including getting rid of those air-leaky quick-disconnect fittings. Don't forget a pre-strainer before the fuel pump, to prevent the debris in the tank from causing you any further grief.
Could the tank be building a vacuum due to no venting? A couple of miles would be just about right for this to happen.
If your return line is working ok, I would run a hose off that tee you installed to your vacuum gauge and tie wrap the gauge to the windshield wiper so you can read the gauge. If the vacuum builds gradually as you drive it, your tank is not venting properly.
Rich and the others make a good point about the hutch mod, in my opinion
Larry
Could the tank be building a vacuum due to no venting? A couple of miles would be just about right for this to happen.
If your return line is working ok, I would run a hose off that tee you installed to your vacuum gauge and tie wrap the gauge to the windshield wiper so you can read the gauge. If the vacuum builds gradually as you drive it, your tank is not venting properly.
Rich and the others make a good point about the hutch mod, in my opinion
Larry
will try that now....does anyone know if that sending unit should be sitting flush on bottom of the fuel tank or not?
next to the sending unit there is 1 vent line on back of tank, blew through it air passed easily so vent is open to tank. there is a line on front of tank approx 1/2" diameter... hose is deteriorated, don't know what that hose goes to, also;
i took fuel bowl back off to bench test for leaks and found that fuel drain was not leaking under pressure but fuel pressure regulator was leaking small amount even when i blocked off injector lines and blew through fuel inlet line with my mouth. shouldnt that stay sealded totaly until it reaches 60 psi and then return fuel to tank? i dont get it because it can sit awhile and still have pressure in fuel bowl. i really think i missed something.
This is a picture of my tank when I did the mod. The two small ports (one at top of screen and other at bottom) are vent lines.
I also believe they were connected together, but cannot remember for sure. I do know that the vent cover you see in the picture below was in line with the rearmost vent.
next to the sending unit there is 1 vent line on back of tank, blew through it air passed easily so vent is open to tank. there is a line on front of tank approx 1/2" diameter... hose is deteriorated, don't know what that hose goes to, also;
i took fuel bowl back off to bench test for leaks and found that fuel drain was not leaking under pressure but fuel pressure regulator was leaking small amount even when i blocked off injector lines and blew through fuel inlet line with my mouth. shouldnt that stay sealded totaly until it reaches 60 psi and then return fuel to tank? i dont get it because it can sit awhile and still have pressure in fuel bowl. i really think i missed something.
When is the last time you replaced the vibralok sleeves on the fuel lines at the filter bowl?
10-08-2017, 06:54 PM
