Does injection pump allow fuel through return with key on and electric pump?

[Shawn MacAnanny]

While installing the new injectors and pump I am removing the factory fuel filter and replacing the mechanical pump and filter with a cat pump and 5 micron filter under the frame. I already had the braided stainless line made up to directly connect to the injection pump. I know there is an air vent on top of the fuel filter to bleed air and return fuel, and there is a a return on the injection pump. So being I am directly connecting to the injection pump if air were ever to get into the line it would have to go through injection pump to get out. I know if changing the filter I can have key on and crack line to bleed without cranking but is the ip designed to allow fuel to go through it without it rotating? That'd eliminate any air since it an electric pump and the waiting 10 seconds before glow plugs turned off would purge anthything.

 

[icanfixall]

Mel tells me this will happen but... When he installed my second new Moose pump at the 2009 rally we never did see fuel come out the return off the top of the pump. He told me this is how he changes a pump and never has to bleed air from the hard lines.

 

[MTKirk]

While installing the new injectors and pump I am removing the factory fuel filter and replacing the mechanical pump and filter with a cat pump and 5 micron filter under the frame. I already had the braided stainless line made up to directly connect to the injection pump. I know there is an air vent on top of the fuel filter to bleed air and return fuel, and there is a a return on the injection pump. So being I am directly connecting to the injection pump if air were ever to get into the line it would have to go through injection pump to get out. I know if changing the filter I can have key on and crack line to bleed without cranking but is the ip designed to allow fuel to go through it without it rotating? That'd eliminate any air since it an electric pump and the waiting 10 seconds before glow plugs turned off would purge anthything.

I was trouble shooting some fuel routing issues on my truck a while back and I ran my electric pump with the engine off. I did get a very small amount of fuel to come out of the Injection pump return line, but I don't think this would do a very good job of bleeding your system. EDIT for clarity. The engine was not running; But, the key was on and thus so was the fuel supply solenoid.

Because I run a dual fuel system for running on vegetable oil, I have had to eliminate the small return line at the top of the filter. I REALLY WISH I could figure out a way to get this back, there are numerous ways for air to get in your system and this stock setup would have saved me numerous roadside purges of the schrader valve- always at the worst time. And you're running a system without even a schrader bleed? ENJOY!

Seriously, I would try to integrate at least some kind of manual bleed (automatic would be even better). All it would take is a tee fitting with a valve (or small orifice) that controls a line going back to your return line.

 

[icanfixall]

I hope you left the return line check valve in the top of the injection pump when you removed the small return line fitting.

 

[Shawn MacAnanny]

I didnt realize that was a check valve but i am leaving that part rubber and the elbow it is. I'll take some pictures once i get everything mounted.

 

[Shawn MacAnanny]

I'll have to look at air bleed options, maybe a 4psi back pressure valve and tee off of the feed line to the IP or something. I can easily break the line at the IP to bleed air out, and if the top return of the pump constantly bleeds back to the tank i would think that should pass any air out, but there shouldnt be any air getting in the system. All tanks, pickups, and lines are brand new.

 

[OLDBULL8]

When ever you Open any line or fitting in the fuel system your going to let air in.

The check valve on top of the IP Opens by pressure the Fuel Solenoid Opens when energized to let fuel pass thru the IP thru the check valve to the return line that goes to the injectors and back to tank.

So, with an electric lift pump, when the key is turned on, you are pressurizing the whole fuel system, yes, fuel will pass thru the IP whether it's rotating or not rotating. Depending on where there might be air in the system, it could take a few minutes to bleed the air out thru the IP with a fuel system like you are installing.

1st pic is with the check valve assembled on the IP return line ell.

2nd and 3rd pic's are the check valve.

4th pic is the internals of the IP fuel control on top of the IP with solenoid cap removed.

 

[Shawn MacAnanny]

Thanks! that's exactly what i needed. I i know i'll need to prime it after injection pump install, and any fuel filter change but i was figuring key on, so fuel pump on, crack the line at the injection pump via the JIC fitting to bleed out most of the air until i see fuel, then tighten and the rest should pass through the injection pump. I was more concerned about day to day driving how much air could actually possibly enter an be bled out. I think it will be fine If not i'll at a tee and return line before the injection pump. I plan on flushing a few gallons through the new lines and fittings and returning to the tank with a temp rubber to fuel return to make sure everything is clean before entering the new injection pump.

 

[Shawn MacAnanny]

Here's what I have now, not done mounting or wiring and hose still needs a clamp. But there's so much more room without the factory filter and olive orings lines. This pumps is good for 40gph, and 7-8psi max. The pre filter is 10 micron, 2nd filter on pump is 5 micron

 

[icanfixall]

Here's what I have now, not done mounting or wiring and hose still needs a clamp. But there's so much more room without the factory filter and olive orings lines. This pumps is good for 40gph, and 7-8psi max. The pre filter is 10 micron, 2nd filter on pump is 5 micron

Very nice setup. I don't see any hard line clamps on your lines to the injectors. Is this because you are installing the injection pump? Please remember to install those clamps. Otherwise you WILL break a line from the fuel pulses vibration. I broke number 2 cylinder and that line is at the bottom of the injection pump head. Long story but the dealer charged me nearly 400 bucks to replace the line... I was a newbie and very young once. I paid to learn but now I teach others how to avoid getting screwed by dealers.
I found those bolts are just not long enough for my fingers and tools on the line clamps so. I lengthened them and tape the nut in a combo wrench and stick it under the clamps. BTW those clamps are hard as hell to hold together and place the nuts and bolt thru them. I purchased a cheap ass pair of very small vice grips. Squeeze the clamps together and easily place the nut and bolt thru the clamps.. Works great for me..

 

[Shawn MacAnanny]

Yeah I haven't gotten around to putting them back on yet or running the return line from pump, still modifying glow plug harness and relocating controller, there were 2 on the left side and none on the right so I'll add one to the right and one to the left. I noticed they looked like they'd be a pain I have some other nuts and bolts to use. I may steal the clamps from the parts truck I have to add more eventually.

 

[Shawn MacAnanny]

I'll probably build a rock gaurd for those filter housings too just to be safe. I made a radiator shrouf and mounted the fans to replace the clutch fan - i only had half a shroud anyway and ive been through 2 water pumps so i wanted to get it off of the water pump bearing. I got the intercooler coolant radiator installed with the fans, just gotta do some wiring then stat running the new intake and mounting the water intercooler over the engine

 

[jhenegh]

I'll probably build a rock gaurd for those filter housings too just to be safe. I made a radiator shrond and mounted the fans to replace the clutch fan - i only had half a shroud anyway and ive been through 2 water pumps so i wanted to get it off of the water pump bearing. I got the intercooler coolant radiator installed with the fans, just gotta do some wiring then stat running the new intake and mounting the water intercooler over the engine

That looks like a nice setup. What are you using to control the 4 fans?

 

[Shawn MacAnanny]

I'm waiting on one sensor that's going in the water pump, on at 200, off at 180, that'll control the bottom 2 fans, the top 2 have an adjustable thermostat that'll have the probe right at the radiator inlet from the thermostat housing that I'll adjust from in cab based on what maintains the best temp.

The intercooler fans will have an adjustable thermostat too that I'll play around with having inlet and outlet temp and it probes to determine best intake temp for mileage. I'll have all fans and coolant pump for intercooler wired into 120amp relay that's on a 60 second ignition timer that'll delay power to them so alternator will have time to catch up with glow plug drain. I am also installing 250 amp alternator to make sure there will be enough power at idle for 6 fans, coolant pump and fuel pump. I expect the 2 fans for the intercooler will keep the radiator close to temp 80% of the time. I drive pretty much all highway and very rarely tow anything.

 

[Agnem]

The primary pump in the IP does a pretty good job of blocking fuel flow when the pump is not rotating. Some will slip by, but not in great quantity. I could take a really long time for fuel to appear at the pump return. The problem with not having a place for air to bleed off between the lift pump, and the IP, is that when your tank gets low and you go around a corner, or hit a bump, invariably, air will intrude. Air in any quantity wreaks havoc with the internal case pressure and will affect your internal timing advance. So without an air bleed, you can encounter anything from really erratic running, to an unwanted shut down.