Compression Ignition Addict
Join Date: Jun 2012
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PROBLEM GONE!!! WTF!!!?
Well, I don't know what the @#$K is going on with this truck, but it is running fine at the moment. So I tapped the fuel pressure gauge, and realized it wasn't getting power. The harness was loose, and when it re-connected, the pressure reading climbed to about 75psi. I backed it off to about 50psi, and PRESTO-CHANGE-O. The rough running disappeared. Turns out, the truck does NOT like to have the psi that high. I don't know whether the fuel was bypassing one or more of the injector nozzles because of the added pressure and (VERY) old injectors, but in any case, it is running great right now. I even set the EVO-CTS to "extreme" and cranked it up. The truck runs awesome.
I still believe I need to replace the injectors with new rebuilds, but now the problem is a little bit more back-burner than immediate.
The other possible scenario is that by getting up onto/into the engine bay to get to the pressure sender and FPR to change the pressure, I might have re-connected something that was loose. I seriously doubt that took place, because i checked and re-checked all the harnesses by unplugging and re-plugging them all back in with the engine running, with no change in smoothness until I backed down the fuel pressure to just over 50 psi.
Because I changed the mechanical pump to electric, the water-in-fuel sensor, fuel heater plug, and low pressure indicator are not being used, and are cable-tied together, out of the way. There was no easy way to utilize them without re-using part of the old pressure regulator, which I did not want to do. Maybe the stock pressure sender, which I thought only indicated too low of pressure, triggering the "fuel filter" light, also would have indicated a DTC for high pressure? Whatever, it's running.
1996 F250 eclb, 4x4, 7.3L PS
420,000 mi and counting
Viair 444C/6g air tank on frame, Hadley air horn, Hella auxiliary reverse light, DIY WVO conversion; Efuel, dual FuelLab FPR's, 90g RDS tank, aluminum tube-in-heater hose, hotfox heated fuel pickup, copper coil-wrapped filter, 40-plate FPHE, auxiliary coolant pump, 2000lb winch-crane bolted to the frame. Ranch hand front bumper.