injectors

[thunder one]

hi i have a 1986 928s i need to take out the injectors an clean them can somebody tell me where can i find a diagram or pictures of how to remove them an replace them [thanks]

[curtisr]

From Pelican Technical Article: 944 Fuel Injector Clean & Reseal comes this helpful tech article:

Warning/Disclaimer: This procedure involves working with your fuel system, as well electrical components in close proximity to your fuel system –there is a chance of seriously injuring/killing yourself or causing serious damage to your car if you screw up – gasoline burns, gasoline vapor explodes, and electricity can shock you, cause sparks, and other assorted unpleasant things – ‘nuff said.

Tools Required:

10mm socket
Small Flathead screwdriver
Adjustable wrench
2 hose clamping pliers
Rags for clean up
Q-Tips
A couple of medium sized Baggies and rubber bands
4 x Fuel injector seal kits (Pep Boys – Borg-Warner kit #274081, $2.49 each – comes with O-rings, washer, and the “hat”)
2 cans of carburetor cleaner
2 cans of brake cleaner
New, clean ATF
1 short length of hose to fit the injector
Hose clamp for the same
Compressed air source
Battery charger with 2mv setting

Optional:

2 wires, about 12 – 24 inches long
1 Push button, momentary, normally open switch. (about $3.00 at radio shack)
2 alligator clips

Removal Procedure:

1. Depressurize your fuel system –by pulling the fuel pump fuse and running the engine until it quits.

2. Disconnect the negative from the battery

3. Disconnect and remove your spark plug wires – now is a good time to inspect for damage – replace as necessary

4. Put a baggie over your distributor – secure with rubber bands (Note spilling fuel in your distributor can cause an explosion when you start the car)

5. Clamp the fuel feed and return lines running to the fuel rail

6. Disconnect the vacuum hoses running to the fuel regulators

7. Remove the plastic fuel rail cover (depending on how your wires and hoses are routed, you may have to do this earlier)

8. Disconnect the wiring harness from your fuel injectors, move the wiring harness out of the way

9. Unbolt the fuel rail from the engine

10. Pulling lightly, remove the fuel rail/injector assembly from the car, you can flip it upside down and rest it on the shock tower.

11. Using your drip pan and the adjustable wrench, loosen the large bolt on the front of the fuel rail and drain the fuel from the rail (NOTE: if you have to remove the bolt, DO NOT lose the sealing ball inside the bolt)

12. Pry the retaining clips off of the injectors

13. Grasp the injector and pull it out of the fuel rail – you may have to wiggle it a bit to work it loose – keep your injectors in order – make sure that injector #1 goes back in cylinder #1 (this isn’t a requirement, but it seems like a good idea to me)

Cleaning Procedure: Now that the injectors are off, take a moment to clean the injector mounting points on the fuel rail with carb cleaner and a Q-tip. Do the same for the injector ports on the engine and the fuel injector wiring harness terminals

1. Spray the injector with brake cleaner to remove dirt, grime etc.

2. Work the little plastic “hat” off of the injector tip (Warning!: Don’t damage the actual injector tip)

3. Slide the O-ring and plastic washer off of the injector

4. With the small screwdriver, work the top O-ring off (Where the injector connects to the fuel rail)

5. Spray it down with brake cleaner again, use a lint free towel to wipe the O-ring surfaces down

6. Fill the injector with carb cleaner, prop it up (not resting on the tip!!!) and let the cleaner drain through it – you can remove the O-rings, hats, and the like from the others while it is draining.

7. Attach the hose to the injector tip, again, being extremely careful not to damage it, secure with the hose clamp.

8. Now it is time to backflush the injector – to get the injector to open up, you must apply voltage to the injector. This is done with the battery charger. The trick is, you must “Pulse” the voltage, DO NOT apply constant voltage to the injector. You can do this by turning the charger on and off repeatedly, or, you can wire a simple circuit to make this much easier:

A. Take 1 wire, attach an alligator clip to one end, strip the other end.
B. Take the other wire, cut it in half, strip all ends, attach an alligator clip to one end, then wire the switch to the pieces of wire, making one wire again.
C. Connect the alligator clips to the injector terminals, the bare ends of the wire to the battery charger wires.

9. Fill the hose with carb cleaner,.

10. Turn on the battery charger, apply a compressed air source to the end of the hose. If you rigged up the switch assembly listed above, there will not be any power going to the injector until you push the button, if you didn’t, you have to turn the charger on/off every couple of seconds, with the switch, just repeatedly push the button.

11. After the hose is empty, do it again.

12. Now flush the injector the other way twice.

13. Spray the injector down again with brake cleaner.

14. Time to reassemble the injector. Holding it tip up, slide the washer, O-ring, and then the hat from the kit. Flip the injector over and install the other O-ring.

15. Lube the O-rings with clean ATF, reinstall on fuel rail.

16. Repeat for the other 3 injectors

17. Fuel rail installation is the reverse of removal.

18. After installation, put the key in the ignition and turn the key to “ON” for a few moments to build fuel pressure back up.

19. Start the car.

This procedure took me about 60 minutes to accomplish. Since it was done, I’ve noticed the engine runs a little smoother, and the acceleration is a little quicker.

Michael Van Bibber (AFJuvat)
Vanbibma@cfl.rr.com

Comments and Suggestions:
John_AZ Comments: There is a mesh screen/filter inside the top of the injector. If you can find a source for the "Bosch Universal Crush Filter" you can remove your old screen and then do the cleaning. Install the screen when finished.

As well, here's a great video that featues a home-made core extracting tool:

[stepson]

After #17, I would jumper the fuel pump relay and check for any leaks after the fuel pressure builds. Only after I was satisfied that no leaks occured anywhere in the system front to back and top to bottom would I energize the ignition system and/or attempt to start the car.

[stepson]

You could also buy a connector that will clip right on an injector to energize each injector with the battery/charger. I use Berrymans B12 in lieu of the carb cleaner (same effect) and apply a mityvac suction to the top of the injector to achieve the reverse flow. Pulse the injector until the B12 begins to flow through the top of the injector with the vacuum. This works really well with injectors that have been sitting for a while and are gummed up.

I'm sure that your way will work just as well.

Nice write-up.

[mikebloomfield]

Just a question, since I'm doing this soon;

I have an 82. Do I have to do an additional step where I remove the screw from the tear-drop shaped bracket in between the injector and the engine? Or does that stay in the engine? I've seen pictures of them out of the car, but still connected to the injector.

[MPDano]

That Video is CIS (Mechanical Injectors) BTW. He has Electronic Injectors.

[76FJ55]

Just another option to consider; for the 86 you can get a new set of marched flow Ford racing 4 hole disk type injectors for just a bit more than what it cost to have your stock 25 year old injectors cleaned.