Replacing injectors

Removal of all 6 injectors

1. Disconnect both negative battery cables from both batteries. Cover and isolate ends of the negative cables. This is just done for pure safety for you and the electrical system.
2. Remove the decorative cover (10 mm) breather tubes hooked to the valve cover.
3. Remove the valve cover. There are six 10mm bolts holding the valve cover in place. 

4. Remove all the 8mm nutted electrical connections on top of all injectors and unplug the 3 electrical connectors on the driver side of the lower valve cover.

5. Remove the lower half of the valve cover which has seven 10mm bolts. Be aware there is one at the very front edge and very rear edge.

6. Remove all 6 exhaust rockers. Make sure to lay them out in the exact order you removed them from the engine. Have a small table covered with rags and set the table beside the truck and from front to rear lay the rockers out in that order.

7. Remove the intake horn. There is one 10mm bolt holding the dipstick tube, then 11m (7/16) socket loosen the intake boot clamp. Then there are four 10mm bolts holding the intake tube to the intake manifold and grid heater. lay them over to the driver's side out of the way.

8. Remove all 6 injector lines from the rail to the head. There are 10mm bolts holding some of the lines are bolted to the intake cover plate. Using a 3/4 inch wrench you'll loosen both ends and remove each line. Again, lay them out in the exact order next to each cylinder rocker arm in order. 
9. You'll need a 24mm open-end wrench or boxed end that is thin. Remove each connector tube nut. Using a flat-blade screwdriver and carefully pry each tube from the cylinder head. Suggested to lay each connecting tube next to each cylinder rocker arm for inspection.
10. Remove all twelve 8mm bolts holding the injectors in place. 
11. Using a flat-blade screwdriver and place the tip under the hold-down collar of each injector and either twist the screwdriver to lift the injector out or lever off a head bolt and lift each injector out. Suggested to lay out each injector next to its cylinders rocker arm for inspection. 
 

WARNING: Do not attempt to replace just one injector that is damaged. Injectors should be replaced in complete sets.

NOTE: I also highly suggest that you do not replace with Bosch stock injectors, Bosch stock injectors are not flow match or pop tested before sale. This means you do not have a matching set for your truck and injector failure rate is much higher on unmatched injectors. You should buy a set of injectors that have been popped-tested and flow match for your application. 

WARNING: There are differences in injectors between early and late 3rd Generation trucks do not exchange early and late injectors engine damage will occur. 

NOTE: If your truck happens to be an automatic transmission be aware that the added power of injectors might make the transmission slip. This depends on the final ratio of the truck to the ground and oversize tires will impact this issue.

Inspection

To inspect the injector you will need to clean off all the fuel and oil off the injectors. Brake clean and rag should suffice.
1. Look for burrs or wear on the injector inlet.
2. Check nozzle holes for hole erosion or plugging. You will need a magnifying glass to really see the nozzle.
3. Inspect end of injector nozzle for mechanical damage.
4. Look for cracks at injector nozzle end. 
5. If any of these conditions occur, have the entire set of injectors rebuilt.

Installing

Most injectors are rebuilt these days there are a few companies that do sell new flow match injectors like Big Bang Injectors (BBI). 

1. Unpackage all 6 injectors and verify that the copper shims are included on the nozzle. If not you will need to install the copper shims. If the shim slide on easily you will need a small dab of axle-bearing grease to hold the shim in place during installing. A new copper shim with correct thickness must always be re-installed after removing injector. Measure thick-
ness of injector shim. Shim Thickness: 1.5 mm (.060”)

2. Thoroughly clean fuel injector cylinder head bore making sure there are no debris or old copper shims in the bottom of the bores. You can use a shot of brake clean and a rag to wipe out the holes. 

3. Most injector suppliers typically already have the o-rings on the body of the injector. If not make sure to install that o-ring at this time and lightly lube the o-ring with clean engine oil.

4. Install the new injector. Pay attention to the location of the inlet port on the side of the injector and it should face the intake manifold in line where the crossover tube goes. Push down the injector hold down collar and seat the injector completely into the bore. 

5. On each injector you want to tighten the two 8mm bolt alternately till 44 inch/pounds. This just insures the injector is fully seated in the bore. I typically back off this torque to allow the injector to find center of the cross over tube in the next step.

6. Install all 6 crossover tubes. Torque the crossover tube nut to 11 foot/pounds. This will now seat the crossover tubes into the port of the injectors. 

7. Now torque all the injector hold-down bolts to 89 inch/pounds. Make sure to alternate back and forth and not get one side buried into the bottom. Should be even and level. 

8. Torque the crossover tube nuts to 37 foot/pounds. You will need a 24mm crowfoot or like myself I've done enough of these to do it by hand with a standard wrench. 

9. Inspect the o-ring gasket before installing and replace if any damage is seen. Reinstall the lower half of the valve cover. There are seven 10mm bolts. Remember the front and rear have a bolt near the sealing lip.

10. Hook up all the injector wiring back to each injector. There is no polarity to the injector so it doesn't matter which wire goes on which post. Do not over torque the wire nuts the only need 11 inch/pounds of torque. Plug in the 3 engine harness plugs to the lower half. 

11. Install the exhaust rocker in the order you had laid out. make sure the push rods are down in each tappet. The torque on the hold-down bolt is 35 foot/pounds. Be aware that maybe a few cylinders where the tappet is up on the cam lobe but also even a pushrod that isn't seat will look similar make sure the pushrods are in the tappets. If you kept the rockers in order then you will not need to do a valve lash.

12. Install all six high-pressure rails between the rail and the crossover tubes. If you kept them in the order it shouldn't be too hard. Torque the line nuts to 22 foot/pounds.

13. Reinstall the upper valve cover and crankcase vent tubes. The six valve cover bolts are torqued to 18 foot/pounds.

14. Check the condition of the grid heater gaskets replace if needed. Reinstall the air horn and grid heater. Torque the four 10mm bolts to 120 inch/pounds. 

15. Attach the dipstick tube with the one 10mm bolt. Tighten snug.

16. Tighten the intake boot clamp.