"Re-Priming" Fuel System on 1993 7.3 IDI

OkieDieselMan

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I just finished installing a Banks Turbocharger onto my 1993 F250HD and drained my Front & Rear Fuel Tanks, as I wanted to get rid of the old Diesel that was approx. 8 months old.

I am now adding fresh Diesel to the Tanks and want to make sure that I "prime" the Fuel System as much as possible, so they Engine will "fire up" fairly quickly (i.e., with as little "air" in the System as possible).

I've got some ideas on how best to "re-prime" the Fuel System....just not sure of the "correct" way to do this??

I've thought about removing the Schrader Valve at the Fuel Filter Housing on the Engine and connecting my MityVac MV7300 Vacuum Tank to the "Hole" and using the Vacuum Pump to, hopefully, "pull" fuel all the way from the Tank to the Filter....But I don't know if this would really work??....Are there obstructions/valves? or ?? in the System that would not let the Mityvac Tank do the job??...or Would this work?

Any info. would be appreciated.

Harold
 

DirtyWood

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You should be able to pull fuel up to the filter head--the injection pump is capable of sucking fuel from the tanks without a lift pump so there are no normal obstructions/valves to worry about. I would think you could remove the Schrader fitting or the return line fitting from the filter head and install a barbed fitting that matches the diameter of the Mity-Vac hose--1/8th NPT for the schrader and return line fittings.

A more PITA method would be to manually rotate the engine but it should work. I recently rebuilt the heads on my truck and when I was checking to make sure the engine rotated smoothly I noticed that fuel was pumping out of the lift pump even with relatively little engine rotation--of course I did this when the fan was still removed so it was easy.

If your batteries are good then the easiest thing is probably just cranking the engine over by arcing the starter solenoid on the fender while holding open the Schrader valve so the air purges, at least that's what I would do. I would also disconnect power from the injection pump so the engine won't try to start, and maybe even disconnect the glow plugs to save some battery.

Also, I have the Sidewinder turbo on my truck and love it. So far the best performance seems to be with timing between 7 and 8 degrees BTDC.
 
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DougBoy66

That is a HORRIBLE idea!!!!!! What time?
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I hooked a locking chuck to the Schrader valve with the chuck hooked to an oil vac hose. Just pulled out fuel until the bubble stopped then disconnected the chuck and put the cap back in the Schrader. I tried pulling the valve out of the valve stem but air gets back in trying to put in the valve. Chuck is much easier and efficient
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