HELP - priming 7.3 IDI

   / HELP - priming 7.3 IDI #11  
Is this something you'll have to do every time you change the filter on a 7.3 IDI engine? Surely there is a better way or nobody would change fuel filters.
 
   / HELP - priming 7.3 IDI
  • Thread Starter
#12  
Seems it depends on how bad you let the air in. On other boards peeps have reported similar problems, having to crank a lot, but some only a little.
I think if I had just took off the filter, immediately put another on filled with diesel, cranked the injectors open, I probably would have gotten going in several cycles. With 30 seconds of crank and 10 minutes of rest it still would have taken a while.
But I had not changed the filter before, it had been done at shops. Whoever put the last one on had tightened the water drain down so tight I had to put it in a vise and use a big wrench to get it off. So by then I just took the night off. Everything then had plenty of air. :(
Another problem is just getting to the injectors, it was a bear to crack the the two just back from the front and their was no access to the front two. Remember it's a van.
 
   / HELP - priming 7.3 IDI #13  
Just a crappy system then. My tractor has no such problem with air in the system and it is a rotary pump too. Then my truck with the 7.3 powerstroke requires no such efforts, just put it on and start the truck.

Having to put a wrench on the injectors for regular maintenance means the system has a bad design.
 
   / HELP - priming 7.3 IDI #14  
There are better ways.

Next time, after fuel system is all buttoned up and before you crank the engine at all, place a hand operated vaccum pump (those brake bleed kits) on the system at any point at or after the fuel filter. My 6.2L diesel has one at the housing. If there is no other place, put it on the return line from the pump only. Pump until the fuel runs clear. Start as normal.

The other trick is to button the system up, and remove the shut off solenoid wire from the pump. Crank for 3 or so rounds of 20 seconds on/ 5 minsutes off. Put the wire back on the pump. Start. It may run a little rough, but should start. By doing this, the shut of solenoid will not allow the pump to fill the injector lines with air. Air goes back to the tank. This is a little more risky the first time because you don't know how many rounds of priming it will take to remove the air. You czan get an educated guess byt he schrader valve though.

I have disconnected the glow plug system and fired these on starting fluid as a lazy way to prime them, killing a worn out 6.9L IDI in the process, so I would advise against that.
 

Tractor & Equipment Auctions

2014 CAT 740B Articulated Dump Truck (A50490)
2014 CAT 740B...
2016 INTERNATIONAL MA025 BOX TRUCK (A50505)
2016 INTERNATIONAL...
2022 Club Car Tempo Golf Cart (A48082)
2022 Club Car...
UNUSED 30PCS Eye Lifting Hooks w/ Crane Hoist (A50860)
UNUSED 30PCS Eye...
2014 Lodal EVOMAG20U300 Side Loader Garbage Truck (A48081)
2014 Lodal...
2014 Ford Explorer AWD SUV (A48082)
2014 Ford Explorer...
 
Top