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Air Injection Valves (AIV) control emissions and allow a small amount of air into the exhaust to improve emissions, however, they are relatively unnecessary and often have age failures such as broken hoses or vacuum issues, another problem is a gurgling sound. Learn how to remove them with this article on NICOclub.com –
I know there is a write-up on this. The other write-up also says you have to remove the fender to get to the last air box. I found this to be incorrect on the 1990 N/A 300ZX.
This AIV deletion “How to” is done with headers and test pipes already installed. If you do this without the test pipes then you will need to plug the “bung” where the AIV is connected to your exhaust system.
TOOLS:
-10 mm socket and ratchet
-Phillips head screwdriver
1. Jack the front of the car up and support with the proper equipment.
fender.
2. Remove front wheels from the car.
3. Remove bolts, screws and plastic fasteners(with the tip of the screwdriver push in the center of the fastener to remove) from the fender liner. You only need to take off the rear part of the fender liner to access the AIV’s. In fact you don’t NEED to remove it. It just makes for easier access and a cleaner end result. If you decide not to remove it you have to crease the liner to keep it out of the way.
4.Don’t forget this one.
5. Remove fender liner to expose the AIV assembly. My fender liner has a rectangle cut out for neons in the wheel well. So yours will look solid.
6. Remove the bolts that hold the bracket for the AIV assembly in place.
7. Remove bolts that hold your starter relay bracket in place. Remove the nut that holds the upper AIV bracket also.
8. Loosen the Nissan reusable zip ties that hold the wire loom from vibration.
9. With the wires loose you can weave the whole AIV assembly out of the fender.
10. Remove the vacuum line from the AIV assembly and trace it back to the AIV solenoid. Leave it attached to the solenoid for now.
11. Replace starter relay and snug wire loom zip ties.(Now would be a good time to replace your starter relay…It is at least 17 years old)
12. Take time to clean the fender liner and clean out any debris on the inside of the fender. In the corner it tends to collect and stay moist when driving in wet conditions. This moisture will rot your fender from the inside out. I found an old mouse house and about a pound of moist dirt.
13. Replace fender liner, bolts, screws and fasteners.(I cleaned mine up with Simple Green and a scrub brush but did not take pics.)
14. Switch sides and remove the wheel on the passenger side.
15. Remove the fender liner, bolts, screws and plastic fasteners. This side is in 2 pieces. Remove both of them.
16. Remove the bolts that hold the bracket for the AIV assembly in place.
17. Remove the two upper bracket bolts. There is also a nut to remove.
18. Loosen the Nissan reusable zip ties that hold the wire loom from vibration.
19. With the wires loose you can weave the whole AIV assembly out of the fender well.
20. Take time to clean the fender liner and clean out any debris on the inside of the fender. In the corner it tends to collect and stay moist when driving in wet conditions. This moisture will rot your fender from the inside out. I found an old mouse house and about a pound of moist dirt.
21. Remove the vacuum line from the AIV assembly and trace it back to the AIV solenoid. Leave it attached to the solenoid for now.
22. Snug wire loom zip ties. Replace fender liner, bolts, screws and fasteners.
23. Remove the two bolts that hold the AIV solenoid and the cruise control unit.
24. Remove the AIV bracket and solenoid. Replace the cruise control bracket and bolts.
23. Unhook the electrical connection on the AIV solenoid. I have found that a “pick set” is very useful when dealing with the old, brittle 300ZX connections.
24. Protect the connection from corrosion with silicone lubricant or dielectric grease as shown.
25. Trace the two vacuum lines on the AIV solenoid back to the engine and remove them. Along with the AIV solenoid itself and all vacuum lines connected to the solenoid.
26. Here you are supposed to cap the two vacuum lines that used to go to the AIV Solenoid.
27. Marvel at all the useless crap removed from the Z.
28.Replace both front wheels. Lower the car. Then torque the lug nuts to specified settings.
Note: I have already taken off the exhaust and replaced it with headers and test pipes. If you have the original exhaust on your Z you will have to purchase two plugs that fit the bung on the Cat pipes.
“That will be all…End of line.”
