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I posted earlier about breaking the return fitting when I R&R'd my fuel tank. A little background. I was cleaning the tank hoping that water or trash was causing the Ex to cut off at idle like turns and traffic lights. Got it put back together and no improvement. I decided now would be a great time to install an AirDog II. I did that and the truck still has the same problems. I completely removed the HFCM and taped offt the wires. The scan shows P0231 and P0232. Fuel pump secondary circuit low and high. I have great flow to the small filter bowl. I don't have a fuel pressure gauge yet. It will not stay running. Help if you can. Thanks.
Check the fuel pump RELAY. Those are contradictory codes, but both indicate a wire problem or relay problem. Relay is the easiest to check first. Does the airdog run and then time out while the truck is running or does the truck just quit running and the fuel pump keeps running?
Thanks NPCCPARTSMAN. I will check the relay. The pump runs any time the switch is on. Until you switch off the ignition the pump runs after the engine dies. FWIW, when I removed the HFCM I cut the couplings off of the wires taped them to insulate and pushed them out of the way.
The only relay I found said fuel htr. There is a 20 amp minifuse that says fuel pump. I would think neither are related to the problem since that fuel pump is gone. The AirDog II has it's own relay and fuses.
Another interesting development. I loaded an ASE tune to see what would happen. Fired up and ran like a champ for 4-5 minutes then back to no throttle response and not cranking except once every 10 tries.Then it acts like the fuel is MIA. Thoughts ? Opinions? even snide remarks?
Bump.
I have about run out of options for this shade tree mechanic. Does anyone have assembly or disassembly instructions for the fuel regulator.Thanks for looking.
The Ex is an 04 6.0L EB. Under warranty it had the EGR cooler replaced and a year later got new head gaskets, heads, injectors and EGR cooler again. Since then I have installed an MBRP turbo back 4" exhaust, SCT tuner, another stock turbo and HPOP ( I think I was robbed. The shop just changed parts until they got it running), AFE Stage 2 intake, an old 1000 model Edge for Boost and EGT gauges EGR delete, ARP headstuds with new washers and o rings on the injectors. It now has 188,xxx miles.