Engine/Transmission (1998.5 - 2002) Most effective procedure for bleeding injection lines

[Gordon Maney]

Is there a best, most effective procedure for bleeding injector lines and injection systems?

 

[JLandry]

Please refer to THIS POST.



John L.

 

[Gordon Maney]

Please refer to THIS POST.

John L.

It only mentions three injectors. Is that due to accessibility? Number 1 is easy. Two seems impossible, and six is, as my father would have said, a bear.

 

[JLandry]

It only mentions three injectors. Is that due to accessibility?

Yes... AND the fact that you can usually get the engine started with only three properly functioning injectors. When started using only three cylinders, the engine will rattle like hell. Then normally within a few minutes any air trapped in the remaining injector lines will be pushed out and the engine will smooth out.



John L.

 

[PC12Driver]

I just learned that you don't have to crank the engine to bleed the lines. I cracked the three easiest injector lines to get to and bumped the starter to get the lift pump to run. I started getting fuel weeping at the head after the second bump. After I tightened everything back up, it started pretty easily with only a little cranking. That was after a VP44 and fuel filter change, so things were pretty dry as well.



Only took 9 years to figure that out.

 

[Gordon Maney]

I would not think the lift pump could push it past the injection pump. Meaning, I would not think there would be a clear path through the injection pump.

I am not saying I don't believe you; I just would never have tried that approach.

 

[Vaughn MacKenzie]

I've never bled lines after injector changes or removing the lines, just crank it with foot to the floor for 3-4 rounds of 10-15 second cranking cycles. Let it sit at least 1-2 minutes between cycles. Has always worked for me. Starts catching eventually then once 2-3 cylinders start working it starts up. I've done this on 12v and 24v trucks.

 

[emarsh]

I will second that, 24V engines just hold pedal to floor and crank for 15 seconds.

 

[Joe Mc]

Now that I think about it when I installed my new VP and was ready to start I cracked the 3 easiest to get to inj line nuts, cycled the LP 2 times and saw fuel coming out of one nut. I didn't expect that at all, so I cycled the LP 1 more time and saw fuel coming from the other 2. tightened them up and gave the LP 1 more cycle and went for it. Scared the heck out of me when she lit right up 1st hit and smoothed to normal idle in a few seconds. I thought for sure something was screwed up - LOL.

I guess when TDC is dead on the innards are lined up and allow fuel to push through? Anyone know for sure?

 

[PC12Driver]

I would not think the lift pump could push it past the injection pump. Meaning, I would not think there would be a clear path through the injection pump.



I am not saying I don't believe you; I just would never have tried that approach.

That's what I thought before I tried it. I don't remember where I read it and got the idea, but I figured it couldn't hurt to try. Like Joe says, it pretty much starts right up. Kinda funny that he says it scared him, 'cause I thought something must have been wrong too when mine lit off so quickly and kept running. A whole lot less wear and tear on the starter and batteries.

 

[ed9824v]

I just did injectors on the boys truck and did notice the fuel bleeding out the injector lines with just the cycling of the lift pumps as well. but still did the 134 bleed while strarting foot to the floor. I wanted to get it running the fastest possible with as little time as possible stressing the vp. not sure if that is all true but will continue to do it that way and not crank like crazy. ED