melmount
Full Access Member
when replacing all 8 injectors, do you have topurge the system before you run it? How about if only doing one injector?
if so how?
if so how?
replacing injectors
- Thread starter melmount
- Start date
Tail_Gunner
CRJ & ERJ A&P Mech.
I didn't purge anything, just made sure I got all the oil & fuel out of the cylinders first so I didn't hydrolock it and bend a rod.
Just start it & run it. It'll sound bad, but the longer you run it the more it'll smooth out and quiet down as the air gets worked out of the oil & fuel passages.
Just start it & run it. It'll sound bad, but the longer you run it the more it'll smooth out and quiet down as the air gets worked out of the oil & fuel passages.
melmount
Full Access Member
how did you get the oil and fuel out of the cylinders? turn it over with no injectors in it?
if so how did you stop fuel and oil flow?
if so how did you stop fuel and oil flow?
BJS
Full Access Member
I used a vacuum pump to suck the stuff out of the cylinders, but yes you do need to clean out the fluid from the cylinders before you put the injectors back in or you risk hydrolocking the motor.
to keep the fuel from coming in you just need to pull the fuse for the fuel pump. for the oil you're not turning it over long enough to get any volume of oil out of the HPOP Or the LPOP All you need is 1 or 2 revoloutions of the engine which should be no more than a second or two, realistically little more than bumping the starter will be plenty. I suggest pulling the IDM fuse also so that there is no possibility of power being sent to the valve cover harnesses.
to keep the fuel from coming in you just need to pull the fuse for the fuel pump. for the oil you're not turning it over long enough to get any volume of oil out of the HPOP Or the LPOP All you need is 1 or 2 revoloutions of the engine which should be no more than a second or two, realistically little more than bumping the starter will be plenty. I suggest pulling the IDM fuse also so that there is no possibility of power being sent to the valve cover harnesses.
melmount
Full Access Member
just the 1 or 2 revolutions before i install injectors, that eliminates hydrolock and its ok to start? I dont have a vacuume pump
BJS
Full Access Member
Once the engine spins and compresses with the starter it will throw the oil/fuel mix out at fairly high velocity, I would suggest pulling the glow plugs too to give you more space for the mix to exit.
The downside to this method is that if there is too much in the cylinder then you risk tweaking a connecting rod. By pulling the injectors front to back you help reduce this risk. Vacuum pumps are on the loan a tool program at autozone and a small hand held vac pump is very cheap insurance in my book. Here is one from autozone that is $30 and will do exactly what you need.
The downside to this method is that if there is too much in the cylinder then you risk tweaking a connecting rod. By pulling the injectors front to back you help reduce this risk. Vacuum pumps are on the loan a tool program at autozone and a small hand held vac pump is very cheap insurance in my book. Here is one from autozone that is $30 and will do exactly what you need.
Tail_Gunner
CRJ & ERJ A&P Mech.
When I did my injectors, I removed the 2 rear most injectors first. The engine has a slight slope to the rear. So by removing the back two injectors first, most of the oil & fuel drained into the rear cylinders. Since I replaced all the glow plugs as part of the same job, I removed them all too. After I vacumed as much oil as I could through the injector hole, I "bumped cranked" the engine and blew any remaining fluids out thru the glow plug holes.
Tail_Gunner
CRJ & ERJ A&P Mech.
FWIW: I have a BD exhaust brake on my truck. Part of that system, is a larger HD vacume pump. I used a collection cup for bleeding brakes. I hooked up a line from the vacume pump to one fitting on the collection cup and ran a long skinny hose from the other fitting. That long skinny one I stuck thru the injector hole to do the "sucking"
BJS
Full Access Member
doh I forget that the SD's have electric vac pumps, and you can use that just rigged up with a collector in the middle. I have used a shop vac, 5 gallon bucket with lid, and some tubing as a vac pump before, and I can say that the shop vac collapsed the 5 gallon bucket but it worked for what I needed to do.
