I was towing my 9500# fifthwheel back through the mountains last weekend. I got a flashing OD off light. I was hopeing for the common VSS on the rearend that might have needed to be changed but the codes they pulled were not that. Evidently what triggered the light indicated some fuel starvation or a obstruction in the fuel feed in the tank. I didn't understand exactly what he was talking about but he wanted to drop the tank to see if any trash might have gotten into the fuel plumbing and caused a blockage. They drove it on flat city streets and could not get it to duplicate itself, but it indicated low fuel flow when they hooked a mechanical fuel flow gauge into the system. This is where they came up with the fuel system blockage. My question would be is there something "MOD" wise that would be justified at this point? I have already done the Harpoon mod where we cut the plastic pipes off of the vent and fill line. I looked at the ITP websight and saw thier system but not sure if this would be benificial to order it and have them put it in. I am not sure, and will get more clarification on exactly what they found and post here. Sorry for the sketchy details but I just wanted to make sure I am getting everything I need. He said that towing and the high fuel flow demand was on the verge of starving things but without the high fuel flow, like on level ground and no camper, things seemed to be fine. The codes also showed a hard shift sometime 3rd and 4th gear and a brief high pressure somewhere in the system. I know it may not make sense right now but I will try to get more details this weeekend. Please let me know if anyone else has seen or heard of anything like this before. I would like to get them to do the in tank mods while they have it down so I was also looking for suggestions of which kit to buy....Thanks for any input, Dave

 

In-tank mod can't hurt but a blinking Over Drive light seems to point more to the transmission having a problem. Fuel starvation is an engine problem and should set a check engine light. I don't know, maybe I'm missing something here. You might have two separate problems. Hard shifting might be a safe mode the transmission goes into when the temperature gets too high.

 

I have the 6.0 cooler installed and it was in the mid 70's all day long. We were about 3 hours into the second leg of the trip when I noticed it flashing. The tranny temps NEVER went above 150. It pretty well sticks to the "no hotter than 75 above outside" as a rule. Even with it over 100 this summer, it never went over 160. I don't believe it was related to the temp, so as I get details I will post them here..Thanks, Dave

 

Dave when I tow, I cannot use even the mildest tune since I modified my fuel supply.
I used to use the Diablo Predator Tow/Haul tune and it would max out at 1200 EGT with about 27 psi boost and the wastegate still connected.
Since I put the fuel pump in the tank it will easily hit 1300 and above on the same hill. I am saying this as a good thing because the fuel supply to the injectors is now unlimited and with no possibility of having any air in it.
I was forced to put the programming back to stock and I still have plenty of power to get up the hill, plus I gained 1.5 mpg doing it. Tow mileage with the tune is 8 mpg and with stock tuning is 9.5.
I had the Hutch mod and eliminate all the quick connects between the tank and the pump inlet.
Simply taking the same pump and mounting it on the end of the fuel pickup changed everything. The engine sounds healthier, makes a ton more mid-range power, and has a very nice even idle sound, even with a cold engine. And I use dino 15-40 oil now, not the synthetic that I used to run with.
If you have the facilities to do so, I very highly recommend doing this mod.

https://www.ford-trucks.com/forums/4...-the-tank.html

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