etcetera Posted May 6 Report Share Posted May 6 This has been driving me insane for over a year. Ever since I got it. 2012 F550 shuttle bus. V10 6.8L with low 54K miles. Nobody can fix it. Had numerous mechanics look at it. One of them replaced the fuel pump. Same thing. It cranks and cranks ad infinitum and sometimes starts and lately not even that. If I use a starting fluid, it will "run" for a nanosecond, then cut out again. I thought it was the fuel pump for sure, didn't fix anything. I know I need to pull the fuel pressure. There is no fuel filter. It's built-in to the pump. I got a certified Ford guy with 20 years of experience look at it and declare it has bad gas. It has been sitting for 6 months since the last trip. It has maybe 5 gallons in it potentially bad and I added 10 fresh ones. No improvement. No start. The thing is, a year ago I completely circulated all the gas out of it and filled it with fresh gas and it still would not start. I think I am going to drop the tank again, maybe some gas disintegrated into residue (The PO from what I understand kept it parked for 2 years) and won't start for that reason even if you add fresh gas to it? It has a 50 gallon tank. If it does start, it will start OK for the rest of the day. That right there is a clue but I don't know what it means. Apparently the fuel pressure is good. Or is it? It runs really nice. Idles OK too. I need a mechanic with really strong diagnostic skills. I am completely frustrated with it. Quote Link to comment Share on other sites More sharing options...
Ranger Smith Posted May 6 Report Share Posted May 6 From another forum If you cranked it over a few times and it did not start , the plugs should be wet.Under the back of your truck should be a fuel pump driver module. Usually bolted to a frame cross member. They were known for corroding where mounted and resulted in starting problems with no fuel. See if you can find it take it down and if corroded where the back of it contacted the metal frame member , it will need to be replaced.If you are sure you are getting fuel under the right pressure then we need to look elsewhere as to why the injectors may not be working. Pulled the fuel pump control module but it’s an all plastic unit. Nothing looked corroded and wiring looked good but I replaced it and the truck fired up. No long crank anymore either. Thanks very much for your help! New part number through ford AU5Z-9D370-J. Quote Link to comment Share on other sites More sharing options...
RV_ Posted May 8 Report Share Posted May 8 (edited) 👍 Edited May 8 by RV_ Quote Link to comment Share on other sites More sharing options...
etcetera Posted May 15 Author Report Share Posted May 15 Forgot to say already replaced the fuel pump control module. And the fuel pump. I talked to a guy at an auto parts place, who seems familiar with the V10, he thinks it's the camshaft position sensor. Plausible? Quote Link to comment Share on other sites More sharing options...
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