I need help I have a 91 f450 with a 7.3 idi . I recently had fuel problems , I now have those resolved and have new ones . I was trying to bleed the fuel system at the injectors to get it cranked and noticed that I could only get fuel out of one injector line . Needless to say I didn't get it cranked could the injector pump be bad or what triggers it (gear?) I am still kinda new to diesels so Im not real sure how its triggered. Is there a way to test the pump or its triggering mechanism. I would really appreciate you guys opinions and thoughts about this issue. Thanks


91 f450SD 7.3 IDI
84 f700 3704v

 

Hold the throttle to the floor while you crank it. Usually helps bleed them out. I have seen a pump shaft break once, that one wouldn't bleed out.

 

I guess you should make sure your pump is getting power to the wires too. Sometimes you can hear the pump solonoid tick as you turn the key on and off (if your ears work good).

 

well the previous problems I had involved me running completely out of fuel up in the top of the system due to fuel pump failure. I did hold the peddle down for a good bit of the time and I thought it was going to crank but it just built my hopes for a big let down . Thanks though I'll continue cyphering the problem.

 

be real sure the filter is full, gets pretty annoying when it draws some down, but the air bubble remains, and no fuel gets through. Hold the schrader open while cranking until nothing but fuel comes out. Then back to beating on the starter some more to clear the injector lines... If you have fuel pulses comeing out of one injector line, then it is still turning, so the shaft is still ok for the moment... the pump should still be ok as well.

 

I have pure fuel coming out of the schrader valve.I spent a lot of battery on getting that . I still only have fuel coming out of the front injector line on the driver side when I open them to bleed the air out . I have never had this much trouble bleeding the lines before but I have never run the engine completely dry of fuel either.Is it possible that the pump is bad inside or is that really uncommon.

 

If one pumps, they should all follow shortly. Take the black return fitting out of the top of the pump and make sure it gets fuel there when you crank too. While you have it out make sure the little glass check ball inside isn't full of junk. That can cause the pump to airlock.

 

make sure you have electrical power to the injection pump and the pump clicks when someone is turning the key off and on. Make sure you give the starter a rest between beatings. They seem to hate manual labor. Perhaps if you used a battery charger to keep the batteries up while cranking, you shorted out the on/off solenoid in the injection pump and you dont get it to turn on.

 

Ive got power to the pump , I have now almost gotten it to crank I have fuel coming out of most of the injectors . Is there an easier way to bleed this air out . thanks for all you guys help so far.

 

There has been a few guys that have put in electric pumps....one guy did it so he could prime his fuel filter when he put a new one in, they are not all that expensive, it's a thought.

 

I got it going guys I appreciate all the help. I'm considering trying to figure out how to switch my two tanks to a self leveling system where both go down evenly and read off of one gauge , no switching involved. Any Ideas ?

 

The only way to do that is do like the big trucks do, have a hose running from the bottom of both tanks to the other.
The electric pump doesn't push past the injector pump, it just gets prime into the IP faster...