I heard these things have possibly 3 fuel pumps. One in each tank and one on the frame rail. If I were to replace the rear tank and pump, possibly with a later model, could I eliminate the mid tank/pump and the frame pump. Both tanks are rusted and need replaced also.

 

Ok, now I have a code 21 temp sensor. code 24 Air charge sensor, and code 95 secondary puel pump circuit. Where do I go now?

 

Did you ever check out the fuel pressure that you have at the fuel rail, key on/engine off???...very important in your case here.

 

No fuel pressure. Today we ripped both tanks out and replaced the back one and eliminated the mid. (rusted out) Checked bothpumps and found that they both work. Also found fuse to selector switch was bad, but not visibly blown. No power to rear tank plug but have power to front connector. Think possible selector switch is bad. Gonna try bypassing it next.

 

I found why this thing wouldnt start. The fuel tank selector switch melted between the power wire and the wire that goes to the pump. Also melted the connector. Cut the wires and spliced them together. Started right up. My question is: could there be another problem that caused this or am I just looking for something that isnt.

 

I have exact same problem.I have replaced all 3 pumps, tank selector switch, all relays, replaced several wires and checked all grounds....the only thing that worked (temporary fix) is to run ignition on hot wire directly to red(hot wire) on high pressure fuel pump (on frame)....for whatever reason this makes both pumps in tank kick on when they are supposed to. The problem is this makes high pressure pump run constantly (probably not good) . Also what is weird .....anytime I unhook the power wire that I jumped to high pressure pump my truck will run/drive fine for 10 miles or so then shut off and wont start until I connect wire again....then runs perfect again. I have been trying to fix this permanently for a year or so and any help would be appreciated.....also I have read this tried and have tried everything suggested and then some.......so if you figured this out please let me know