do you really need to crack injector lines to bleed?

[IDIoit]

new IP's not in question, they take a little more effort.

ive always heard you guys tell me and others that you need to crack the injector lines to bleed the air.

well i didn't do this on my last R&R.

after i got it all back together, i did bleed the fuel filter, but after that, she fired right up.

yes she did run ruff for a few seconds, but the engine settled to a nice smooth idle.

while driving it, i did feel some vibration but i put the pedal to the metal.
and with a nice black plume behind me, the vibration was gone.

i do have a very minor leak on the fuel filter itself, i will be addressing this at another time.

the reason i did not crack the injector lines is because i didn't want fuel all over my clean-ish engine lol

 

[laserjock]

Been wondering about this myself. Don't really want fuel all over my valve covers. Yes I can wrap rags around them but let's be realistic, probably would still have fuel everywhere.

 

[IDIoit]

Mike, if youre running a new IP, then i would say yes. it takes a bit of time for the fuel to run through a dry IP.
my IP was already primed.
but i didn't have to crack the lines.
she fires up first time every time.

 

[icanfixall]

Really no chance of fuel getting all over the top of the engine bleeding air from lines. If I bleed air I do it like Mel showed at the 2009 rally. All fittings tight. Crank for prescribed amount of time. Then crack open lines at injectors and listen for an air hiss or look for fuel. The air hiss really is something you can hear. then the amount of fuel you will see is very little. Mostly just wetting the return cap. Only real reason for bleeding at the injector is to speed up getting the air out and to save the batteries and starter.

 

[laserjock]

So the electric pump won't prime everything? I guess it makes sense it wouldn't prime the injector lines themselves.

Good tip Gary.

 

[79jasper]

It's faster to crack them.
But with enough cranking, it'll work it's way out.

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[homelessduck]

The electric pump helped you not have to Crack them, but it still wont bleed the lines. With a mechanical pump I usually have to crack a couple then it fires and bleeds the rest.

 

[Shawn MacAnanny]

With my electric pump, i primed to the IP when i installed a new IP and misters, i cranked for maybe 10 seconds and it sputtered and died. Then cranked another 5 seconds or so and it started and idled rough for maybe 30 seconds and cleared up. No cracking lines.

 

[F350camper]

I never needed to on my idi. For injector r-and-r, iP r-and-r or long block r-and-r. You've got enough cylinders for a couple of them to light. The 4bt is another story damn thing gets vapor locked with the tiniest amount of air in there.

 

[Shawn MacAnanny]

Yeah i have a 4 cylinder bobcat, atleast 2 injectors have to be cracked if you run it out of fuel, and i had a 2 cylinder ford diesel, that thing took 30 minutes to get started if it ever ran out of fuel even with a gravity fed supply.

 

[icanfixall]

Years ago I would run my truck on the freeways till I ran a tank mt. Then switch tanks keeping my foot on the throttle because its an E4OD trans and it used to finally fuel up and I never stopped.. Last time it rolled to a stop so I never did that again. Sitting on side of any busy freeway is no fun. That was back when I had no air bleeder line off the filter. Truck came that way and I finally figured it out that I needed this filter vent line. An electric lift pump can fill everything but not the injectors or the hard lines. Mel showed me how to watch as an electric pump fills the injection pump till it shows fuel coming out of the return line on top. So far I have never been able to prove this on my own. But I watched him do it once so it does work. Sadly not for me with my Karma.....

 

[david85]

Years ago I would run my truck on the freeways till I ran a tank mt. Then switch tanks keeping my foot on the throttle because its an E4OD trans and it used to finally fuel up and I never stopped.. Last time it rolled to a stop so I never did that again. Sitting on side of any busy freeway is no fun.

I only got away with that once or twice. On the third time, it died a few seconds after a hard acceleration from a stoplight. I was coasting dead stick on the shoulder while cranking at 30 MPH before it fired back up. Felt kinda silly having to pass that RV again. Fortunately, it was not a busy highway. Cruising on flat ground was easier to catch but it really isn't good for the injection system to run them dry anyway.

 

[OLDBULL8]

Think about it this way.
If the injector lines are empty of fuel, cranking, turning the IP to fill the lines takes a bit, just a very little fuel is injected into the lines at each IP revolution, air in the lines has to be compressed by the fuel injected into the lines by the IP, until fuel reaches the injector to pop it open and expels the air along with a little fuel, engine will sputter, too much intake air and not enough fuel for a good power stroke. Until all the air is out of the lines or some of them, the engine will run rough.

By no means can a lift pump inject fuel into the injector lines, I have never seen a lift pump, electric or mechanical that can produce 1900 PSI, IP has to do that.

 

[chris142]

I never have. Crank 20 seconds or so and it fires up

 

[FORDF250HDXLT]

i never do either.not even during an ip change.crank full 20 secs.let starter cool.crank just a few more secs and she's idling.rough but idling.then it's time to unleash the moose!

side note; i should change my screen name to; walks with moose.