Hey everyone.
I posted this deep in a thread about changing spark plugs, then figured it was worth a post just so folks could find it. As a general rule, fuel injectors don't need much more maintenance than periodic detergent gasoline (top tier), and/or a periodic fuel injector cleaning through the gas line. In spite of all the advertising that suggests you can get "like new" injectors, cleaning them only removes deposits. Over time, injectors suffer from wear and tear. They have moving parts! Additionally, too many additives can actually increase the port size (resulting in the fuel spray going from a fine mist to a blob). Leaking injectors will degrade fuel economy (if leaking into the engine), and often will show up as a rich code. For the most part, modern fuel injection engines are able to compensate for the normal degradation over time, but there's nothing like a NEW injector to restore actual power loss resulting from wear and tear. No amount of additive will do that.
As a general rule, I recommend to my customers to consider changing all their injectors after 80K miles at the first sign of trouble on a single injector, or at about 140K miles if they intend to keep it for 20K+ more miles.
If you do the job yourself, you'll save a bunch of cash. It's also not a hard job!
Additionally, it's very common (in fact, it's happened in every vehicle I've done at 120K miles or more) that the vehicle will pick up a 1-2MPG gallon, as a result of restored power and more efficient burn.
Why else should you maintain them by replacement? Well, I've seen more than one engine completely shot as a result of a fuel injector failing. A $50 part cost the owner $3500 in repairs. (I was one of those many years ago and just scrapped the thing).
Again, there are those that would say "if it works, why replace it?" My answer above is the meat. I'd like to add, also, that we all change out spark plugs while they're still working; fuel injectors should get the same love.
Time Cost/value:
The first time you do this, it'll probably take about an hour and a half, because you'll be slow and careful. This generally takes me about 30 to 45 minutes to do a full injector swap, barring any weirdness. TOTALLY worth your time, btw, as the dealers will charge upwards of $1200 to do this! (injectors will run $350 - $700 generally for v-6 and v-8 applications, easy to check, just hit an online auto parts shop)
Ease of Repair:
Easy to Medium
Personally, I think it's easier than many spark plug replacement jobs, because, generally, the injectors are more accessible.
Usually, I only need one or two sockets (8mm and 10mm), but sometimes I find an engine that needs something else. For the most part, though, a simple socket set is all that is needed. Nothing special here.
Materials:
Rags, clean motor oil, new injectors, Socket set
Caution: As with any fuel-related repair, make sure you do this in a WELL ventilated place, and no smoking while working on the Truck! It also helps to do this on a CLEANED engine (no gunk getting into the injector slots), and on a cool engine (no burned hands). Make sure the battery is disconnected at the right time, too!
Instructions:
Start by depressurizing the fuel system. If your truck is equipped with fuel safety cutoff switches, find it and pull the electrical plug from it. This will disengage the fuel pump. Then try to start the engine (it will turn over, but not start). This will pull any fuel from the lines and depressurize them.
Disconnect the battery.
If you don’t have a fuel safety cutoff switch, you can depressurize the line by finding the pressure check valve (usually on top of the rail) and depressing the valve. This will spray fuel everywhere, though, and is messy. If you have a fuel pressure tester, it’ll come with a valve checker and hose for this purpose making it far less messy. It’s not necessary though.
The last resort is to pull a fuel line, that’s REALLY messy. Make sure all fuel is mopped up and dry before proceeding. No sparks here!
Next, pull any components that restrict access to the fuel rail on the engine. On a V-8 you’ll need to do this for both sides of the engine, as the rails will be on both sides. Most Chevy trucks will need the following removed: engine shroud, air intake, vacuum tubes, electrical plugs, and bolt-on engine accessories.
Next, disconnect the fuel rail bolt securing the rail to the intake or engine.
Disconnect the electronic plug from each injector. Push the plug away from the rail.
At this point, you’re ready to pull injectors (not so bad, huh!) Basically, since you’re doing all the injectors, just pull the fuel rail directly away from the tops of the injectors (they’re just held on with O-rings). You may need to rock the rail slightly. The rail will pop right off all four injectors will a little pulling.
Remove the injector from the engine by grasping the injector head and pulling it directly away from the engine. You may find again, that it needs a little rocking.
Once pulled, make sure that each injector has the O-ring on the bottom and top. Otherwise, check the rail or hole. The O-rings are larger than the hole in the engine, so there are no worries about it slipping down inside, but occasionally they do remain in the slot.
On the new injectors, check to see if they come with pre-installed O-rings. They should. If not, you’ll need to get O-rings on them (they’re cheap, btw, but you’ll need to get new ones from the auto parts store..> DO NOT USE OLD O-Rings as they’ll have micro-tears or will be hardened, not making a great seal. In fact, it’s a good idea any time you remove the injectors from the rail or engine to replace the O-rings).
Before putting the O-rings on, lubricate them with new motor oil. The goal is to ensure there are no micro-tears in the O-ring that will cause leaks later. The O-rings are fairly flexible and can be either rolled onto the injectors or pressed into place. If the injectors come with the O-rings on, lubricate the O-rings with motor oil while the O-ring is in place.
Put the injector back into the engine by pushing its nozzle first into the hole. Rock it slightly. You’ll feel a slight “pop” as it seats. This is normal. When correctly seated, the injector will resist light attempts at removal. Seat all four injectors in the engine on each side before attempting to connect the rails.
Connect the rails by seating all four injectors under the ports at the same time, then just press downward. You’ll likely have the same popping feeling again, and as with the engine, properly seated injectors will resist removal.
Smear a liberal amount of dielectric grease on the injector plug port (the grease will protect the electronics from corrosion and water). Connect the plug to the injector.
Reconnect the fuel rail retaining bolt or screw, and replace any accessories, intake, vacuum tubes, etc. Don’t put on the engine shroud just yet.
Reconnect the fuel-safety cut-off switch, if you used this method. Reconnect the battery.
Prime the fuel system by turning the ignition key to the “start” position a few times (with several seconds in place). You’ll hear the fuel pump prime the lines. Do this at least 3 times to pressurize the fuel lines.
Inspect the engine compartment for fuel leaks at the injector rails. If you have one, an O-ring isn’t properly seated. Remove the rail and replace the O-ring (as it’s likely been damaged in the process). I’ve never had this occur, but I always check just in case. No use having an engine compartment fire over something as silly as a badly seated O-ring!
Turn off the engine and install the plastic engine shroud. Close the hood and enjoy restored HP, mileage, and engine longevity!
Cheers!
Skippy
I posted this deep in a thread about changing spark plugs, then figured it was worth a post just so folks could find it. As a general rule, fuel injectors don't need much more maintenance than periodic detergent gasoline (top tier), and/or a periodic fuel injector cleaning through the gas line. In spite of all the advertising that suggests you can get "like new" injectors, cleaning them only removes deposits. Over time, injectors suffer from wear and tear. They have moving parts! Additionally, too many additives can actually increase the port size (resulting in the fuel spray going from a fine mist to a blob). Leaking injectors will degrade fuel economy (if leaking into the engine), and often will show up as a rich code. For the most part, modern fuel injection engines are able to compensate for the normal degradation over time, but there's nothing like a NEW injector to restore actual power loss resulting from wear and tear. No amount of additive will do that.
As a general rule, I recommend to my customers to consider changing all their injectors after 80K miles at the first sign of trouble on a single injector, or at about 140K miles if they intend to keep it for 20K+ more miles.
If you do the job yourself, you'll save a bunch of cash. It's also not a hard job!
Additionally, it's very common (in fact, it's happened in every vehicle I've done at 120K miles or more) that the vehicle will pick up a 1-2MPG gallon, as a result of restored power and more efficient burn.
Why else should you maintain them by replacement? Well, I've seen more than one engine completely shot as a result of a fuel injector failing. A $50 part cost the owner $3500 in repairs. (I was one of those many years ago and just scrapped the thing).
Again, there are those that would say "if it works, why replace it?" My answer above is the meat. I'd like to add, also, that we all change out spark plugs while they're still working; fuel injectors should get the same love.
Time Cost/value:
The first time you do this, it'll probably take about an hour and a half, because you'll be slow and careful. This generally takes me about 30 to 45 minutes to do a full injector swap, barring any weirdness. TOTALLY worth your time, btw, as the dealers will charge upwards of $1200 to do this! (injectors will run $350 - $700 generally for v-6 and v-8 applications, easy to check, just hit an online auto parts shop)
Ease of Repair:
Easy to Medium
Personally, I think it's easier than many spark plug replacement jobs, because, generally, the injectors are more accessible.
Usually, I only need one or two sockets (8mm and 10mm), but sometimes I find an engine that needs something else. For the most part, though, a simple socket set is all that is needed. Nothing special here.
Materials:
Rags, clean motor oil, new injectors, Socket set
Caution: As with any fuel-related repair, make sure you do this in a WELL ventilated place, and no smoking while working on the Truck! It also helps to do this on a CLEANED engine (no gunk getting into the injector slots), and on a cool engine (no burned hands). Make sure the battery is disconnected at the right time, too!
Instructions:
Start by depressurizing the fuel system. If your truck is equipped with fuel safety cutoff switches, find it and pull the electrical plug from it. This will disengage the fuel pump. Then try to start the engine (it will turn over, but not start). This will pull any fuel from the lines and depressurize them.
Disconnect the battery.
If you don’t have a fuel safety cutoff switch, you can depressurize the line by finding the pressure check valve (usually on top of the rail) and depressing the valve. This will spray fuel everywhere, though, and is messy. If you have a fuel pressure tester, it’ll come with a valve checker and hose for this purpose making it far less messy. It’s not necessary though.
The last resort is to pull a fuel line, that’s REALLY messy. Make sure all fuel is mopped up and dry before proceeding. No sparks here!
Next, pull any components that restrict access to the fuel rail on the engine. On a V-8 you’ll need to do this for both sides of the engine, as the rails will be on both sides. Most Chevy trucks will need the following removed: engine shroud, air intake, vacuum tubes, electrical plugs, and bolt-on engine accessories.
Next, disconnect the fuel rail bolt securing the rail to the intake or engine.
Disconnect the electronic plug from each injector. Push the plug away from the rail.
At this point, you’re ready to pull injectors (not so bad, huh!) Basically, since you’re doing all the injectors, just pull the fuel rail directly away from the tops of the injectors (they’re just held on with O-rings). You may need to rock the rail slightly. The rail will pop right off all four injectors will a little pulling.
Remove the injector from the engine by grasping the injector head and pulling it directly away from the engine. You may find again, that it needs a little rocking.
Once pulled, make sure that each injector has the O-ring on the bottom and top. Otherwise, check the rail or hole. The O-rings are larger than the hole in the engine, so there are no worries about it slipping down inside, but occasionally they do remain in the slot.
On the new injectors, check to see if they come with pre-installed O-rings. They should. If not, you’ll need to get O-rings on them (they’re cheap, btw, but you’ll need to get new ones from the auto parts store..> DO NOT USE OLD O-Rings as they’ll have micro-tears or will be hardened, not making a great seal. In fact, it’s a good idea any time you remove the injectors from the rail or engine to replace the O-rings).
Before putting the O-rings on, lubricate them with new motor oil. The goal is to ensure there are no micro-tears in the O-ring that will cause leaks later. The O-rings are fairly flexible and can be either rolled onto the injectors or pressed into place. If the injectors come with the O-rings on, lubricate the O-rings with motor oil while the O-ring is in place.
Put the injector back into the engine by pushing its nozzle first into the hole. Rock it slightly. You’ll feel a slight “pop” as it seats. This is normal. When correctly seated, the injector will resist light attempts at removal. Seat all four injectors in the engine on each side before attempting to connect the rails.
Connect the rails by seating all four injectors under the ports at the same time, then just press downward. You’ll likely have the same popping feeling again, and as with the engine, properly seated injectors will resist removal.
Smear a liberal amount of dielectric grease on the injector plug port (the grease will protect the electronics from corrosion and water). Connect the plug to the injector.
Reconnect the fuel rail retaining bolt or screw, and replace any accessories, intake, vacuum tubes, etc. Don’t put on the engine shroud just yet.
Reconnect the fuel-safety cut-off switch, if you used this method. Reconnect the battery.
Prime the fuel system by turning the ignition key to the “start” position a few times (with several seconds in place). You’ll hear the fuel pump prime the lines. Do this at least 3 times to pressurize the fuel lines.
Inspect the engine compartment for fuel leaks at the injector rails. If you have one, an O-ring isn’t properly seated. Remove the rail and replace the O-ring (as it’s likely been damaged in the process). I’ve never had this occur, but I always check just in case. No use having an engine compartment fire over something as silly as a badly seated O-ring!
Turn off the engine and install the plastic engine shroud. Close the hood and enjoy restored HP, mileage, and engine longevity!
Cheers!
Skippy
