LT1/LT4 Injector Replacement ~ Procedure (please read and add comments)
01-28-2002, 09:35 PM
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LT1/LT4 Injector Replacement ~ Procedure (please read and add comments)
I am trying to refine my procedures. Please take the time to read and make comments and/or recommendations for improvement:
:seeya Purp
LT1/LT4 Injector Replacement
1st, remember that a lot of dirt and debris has accumulated around the injectors over the years, so make sue that you have some small brushes and a vacuum cleaner handy to suck up some of that stuff before you pry the injectors out of the manifold. It will also help if you have a white plastic bucket handy. I prefer one like McDonalds sells. I think they call them pickle buckets. Make sure it is clean.
Now, remove the fuel rail covers and locate the Schrader valve in the driver side fuel rail. If you have a fuel pressure test gauge with a bleeder valve, attach it to the Schrader valve and bleed off the fuel pressure into a container. If you don't have a test gauge w/bleeder, then pull the injector fuse, start the engine and run it until you loose fuel pressure. After the engine has stopped, then lay a rag under the Schrader valve and depress the valve to bleed the remaining pressure in the rails.
The top of each injector has a wiring connector attached. The connector is held on with a wire clip. If you squeeze the clip, you can lift the connector off the injector. You can also insert a small thin blade regular screwdriver tip along side of the clips and gently lift them off the injector. Lift each connector and push it back and away from the injectors, but try to leave them in the general proximity of where they belong.
Now, the area around each injector is relatively clear, so take some time and try to clean away and suck up anything that might fall into the injector port when you remove the injectors.
Remove the four bolts that hold the two fuel rails in place, then gently pry the entire fuel rail assembly up, lifting the injectors out with it. This will require you to lift and pry in different locations until one whole side is out. Next, lift the other side out in the same way.
Note that you have never disconnected the fuel lines, nor will you do so. With the fuel lines attached, closely observe the clips that hold each injector into the fuel rails. These slide on the fuel rail, so you should be able to push the clip away from the injector, then grasp each injector and pull it out of the rail. The injectors may put up a fight, as the o-rings are hard and brittle, but with gentle persuasion, you will find the technique for removal of all 8 injectors. Look at the holes where the injectors came out of the rails and if there is dirt or decomposed o-ring material, take a brush and clean.
Now, with the fuel lines still attached, take the fuel rails and swing them to a position so that you can drop the rails into the white bucket. If you removed the fuse, re-install it, and turn the ignition on. The fuel pump will run for ~ 2 seconds. Turn the key off and repeat the cycle until you have pumped some fuel into and out of the rails. Now, look into that clean white bucket and check for dirt and debris. If there is dirt, clean the bucket and flush again. Do this until your fuel rails are completely flushed.
OK, now, if you bought FMS injectors, they are a little shorter than the GM factory originals. The FMS injectors have two clip slots on the end that goes into the fuel rails. You will use the slot that is closest to the o-ring. Now, take each injector and lubricate both o-rings with automatic transmission fluid. You can substitute lubricants, but remember that anything that goes into the intake manifold will be burned and passes your O2 sensors, so make sure that you don't use anything that will foul them.
With each injector securely clipped into the fuel rails, lower the rails back into position and guide each injector into its respective slot. Now, gently push the rail so that each injector is firmly slipped into the manifold, and the fuel rail mounting bolts can be inserted. The fuel rail may seem a little springy, but you should be able to install the bolts without much effort.
Everything else is academic. Make sure that each wiring connector has the clip in place before plugging it on to the injectors. You will hear them click as you push them in place.
Good luck! :seeya ~~ Purp
:seeya Purp
LT1/LT4 Injector Replacement
1st, remember that a lot of dirt and debris has accumulated around the injectors over the years, so make sue that you have some small brushes and a vacuum cleaner handy to suck up some of that stuff before you pry the injectors out of the manifold. It will also help if you have a white plastic bucket handy. I prefer one like McDonalds sells. I think they call them pickle buckets. Make sure it is clean.
Now, remove the fuel rail covers and locate the Schrader valve in the driver side fuel rail. If you have a fuel pressure test gauge with a bleeder valve, attach it to the Schrader valve and bleed off the fuel pressure into a container. If you don't have a test gauge w/bleeder, then pull the injector fuse, start the engine and run it until you loose fuel pressure. After the engine has stopped, then lay a rag under the Schrader valve and depress the valve to bleed the remaining pressure in the rails.
The top of each injector has a wiring connector attached. The connector is held on with a wire clip. If you squeeze the clip, you can lift the connector off the injector. You can also insert a small thin blade regular screwdriver tip along side of the clips and gently lift them off the injector. Lift each connector and push it back and away from the injectors, but try to leave them in the general proximity of where they belong.
Now, the area around each injector is relatively clear, so take some time and try to clean away and suck up anything that might fall into the injector port when you remove the injectors.
Remove the four bolts that hold the two fuel rails in place, then gently pry the entire fuel rail assembly up, lifting the injectors out with it. This will require you to lift and pry in different locations until one whole side is out. Next, lift the other side out in the same way.
Note that you have never disconnected the fuel lines, nor will you do so. With the fuel lines attached, closely observe the clips that hold each injector into the fuel rails. These slide on the fuel rail, so you should be able to push the clip away from the injector, then grasp each injector and pull it out of the rail. The injectors may put up a fight, as the o-rings are hard and brittle, but with gentle persuasion, you will find the technique for removal of all 8 injectors. Look at the holes where the injectors came out of the rails and if there is dirt or decomposed o-ring material, take a brush and clean.
Now, with the fuel lines still attached, take the fuel rails and swing them to a position so that you can drop the rails into the white bucket. If you removed the fuse, re-install it, and turn the ignition on. The fuel pump will run for ~ 2 seconds. Turn the key off and repeat the cycle until you have pumped some fuel into and out of the rails. Now, look into that clean white bucket and check for dirt and debris. If there is dirt, clean the bucket and flush again. Do this until your fuel rails are completely flushed.
OK, now, if you bought FMS injectors, they are a little shorter than the GM factory originals. The FMS injectors have two clip slots on the end that goes into the fuel rails. You will use the slot that is closest to the o-ring. Now, take each injector and lubricate both o-rings with automatic transmission fluid. You can substitute lubricants, but remember that anything that goes into the intake manifold will be burned and passes your O2 sensors, so make sure that you don't use anything that will foul them.
With each injector securely clipped into the fuel rails, lower the rails back into position and guide each injector into its respective slot. Now, gently push the rail so that each injector is firmly slipped into the manifold, and the fuel rail mounting bolts can be inserted. The fuel rail may seem a little springy, but you should be able to install the bolts without much effort.
Everything else is academic. Make sure that each wiring connector has the clip in place before plugging it on to the injectors. You will hear them click as you push them in place.
Good luck! :seeya ~~ Purp
