'97 7.3 F250 Fuel flow/pressure problems? HELP!

J

jennjoslin

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Feb 10, 2011
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Hi all, sorry, a bit of a long post. First I want to apologize about knowing less than nothing about my Ford truck which I use 3x/week to pull my 2 horse trailer. '97 F250 7.3 Diesel with 150K. Bought at 110K and I only put 5k a year on it. Maintained meticulously. Added: New tranny, upgraded tranny cooling system, new water pump, etc...In Sept 2010 my OE fuel pump went and an independent diesel shop talked me into putting in a FASS fuel pump/filter, water separator, new glow plugs . Seemed to be fine (though a bit noisy) for 1,000 miles, then truck broke down (with the horses) one night. Lost power on a hill, ran rough, coasted to a stop. Would start again but shuddering, as if starving for fuel. Towed to shop, they replaced a back exhaust sensor and then broke down again. Then they told me I needed 4 new injectors. What did I know? I replaced all the injectors with new Ford injectors ($4K ouch) and the truck broke down again 1 mile from shop. Shop claimed it was the software upload codes. Supposedly fixed. Truck broke down again 1/2 mile from shop. Finally I towed it to a Ford dealer who diagnosed bad sending units in front and back tanks. Front had 55 psi and back 10 psi. Should have been over 75 psi (that's what they said)? Picked up truck from dealership and sure enough it is starting all over again. Trying not to start, then idle revving a couple of times after I start it. I know it's not right. Returned truck to dealer but they drove it 20 miles and couldn't find anything. I read on the forums about how the FASS fuel pump can suck air if the return isn't properly routed (which is different then stock?). Something about the stock fuel cup in the tanks not filling as quickly as the FASS pump draws from it. I think it's a simple fix but I have a BAR (Bureau of Automotive Repair) suit going with the shop that sold me the injectors I didn't need :doh:, so I need to figure this out soon so:

a) I can have my damn truck going again
b) so I can help prove what was actually wrong with the truck for the lawsuit over the injectors
c) I can get my life back!

A million thanks for your patience and any advice, I know this was a long post, and I apologize for my ignorance. Though I'm definitely more knowledgeable than I was a few weeks ago! Jennifer
 
Welcome!

I would bet your problem lies in the fuel system. It could be the FASS pump, or the fuel lines / return lines. Im not sure how you go about routing the fuel system with 2 fuel tanks. I only have one tank to worry about, so Im no help there.

Do you have a fuel pressure gauge anywhere on the truck?

Do you still use the stock tank selector when switching back and forth between the fuel tanks?

Try searching a little over **here**.

PSN is only Powerstrokes and many guys have ran custom fuel systems with 2 tanks.
 
thats why I dont let anyone work on my truck. if you still have the factory fuel bowl up top (should have been removed with the system upgrade) pull the filter and clean the small screen in the regulator you can also hook a pressure gauge to the schrader valve on the side of the reg. you should have steddy pressure .with a fass you could be sucking air past the line o-rings at the quick connectors on the lines. with the pump running listen as see if you hear the pump changing pitch lit it is sucking air it should maintaine the same sould if no air in the line.
 
MY Q.... Are you running the FASS with the stock mechanical fuel pump? If so it doesn't matter how much psi the FASS will supply cause the mech pump is gear driven.. it will only take what the pump spins. Also you could have sent the injectors out to one of several shops to have them tested. The #8 injector is common to have issues cause it is at the end of the fuel system.
Does the truck ever blow white smoke?
You could also check continuity of the injector/valve cover harness, very common to be bad. They get hot and wires crack.
Also you could check the oil level of your HPOP (high psi oil pump). If you don't have proper oil psi to the injectors they will not perform properly. And i believe there is a fuel psi sensor on the front of the block thats like $17... similar problems will occur
Good Luck!
Beans Diesel Performance is who i would call. You can find them in the sponsor section
 
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