Enthusiast
i was told that in order to remove all the air from the lines when installing a new injection pump it takes 8 hours of cranking? Is this right? it is a electronic pump not mechanical. this is also a new engine. it is a 1995 suburban , i upgraded to a 97 motor. we have been cranking this thing for about 4 hours. we now have some fuel to 4 cylinders and air pressure is bieng felt finally coming out of the other 4 but no fuel yet. is this normal?? Am i missing something here????
No this is not normal. With a dry system should only take a few minutes. Make sure you have fuel to the pump and that your lift pump is working.
Greg
It should not take much cranking at all. No need to crack lines either. I would temporarily run the lift pump manually (hotwire) and blled filter housing, then try again.
Good Day!
You are fortunate that this is a 95 Sub. You can make the lift pump run by: 1) put the shift lever anywhere EXCEPT park or neutral; 2) turn the ignition key to the "crank" position. The lift pump will run, but the engine will NOT crank. (I did a mini-poll - apparently the 95 is the only year where this works.)
Before doing this, crack the fuel filter nut & put a drain tube on the drain fitting. Do the above & wait until you have a steady, strong stream of fuel. This will get you to where you KNOW you've got fuel up to the IP. It should then take very little cranking time, with an injector fitting cracked open, to prime the IP. It will then run rough for awhile, then clean up with a little run time.
Blessings!
Brian Johnson, # 5044
Enthusiast
ok i have fuel going to the ip i only have some fuel going to 4 injectors and that is it!!!! any other reccomendations? is the pump bad? this is a new motor and rebuilt pump that we are installing together. any suggestions? could the timing of the pump be off? would this cause this? im in the dark here and stuck any help would be great
Administrator
You are still airlocked. Loosen all the injector lines at the injector (just a little). Crank until all injectors are getting fuel. It shouldn't take long.
If you get enough injectors bled that the engine will run, you can run it until it clears up, or bleed one injector line at a time while the engine is running.
Crank for no more than about 15 seconds at a time, then wait a minute before starting the next one. It may take only a couple tries, or may be 10.
The reason for needing to bleed is the air prevents fuel from getting to the injectors. The "air bubble" absorbs the pressure pulse, and doesn't let the pressure build enough to pop the injector. You could just crank away with all the injector lines tight, but that will take considerably longer, and could cost you a starter.
No need to cracklines on a DS4 pump. You have and electrical issue. Been there done that a couple of times. I loose connection, broken wire etc. If you have access to a tech 2 would be helpful too.
Good luck
Greg
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