How-To: Delete your AIV's 90 300zx N/A

[rockchucker]

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."

[Zwicked]

Nice job, the photos make it a significant upgrade to previous write ups. I haven't seen the one that says to take the fender off, but that would be a total waste of time.

[mn300zx]

besides removing 9.4 lbs, how does this benefit the Z otherwise, is there any risk?

[marty1mc]

Nice writeup Cory! I will probably use this when I pull my motor as part of the conversion...

[lanceuppercut06]

quick question. why would you want or even need to delete that for ?

[xclusivez32]

to make the engine bay simpler. i deleted mine because one of the rubber hoses was broken, so it wasnt working anyways. it is a very easy thing to delete imo

[marty1mc]

Nice writeup Cory! I will probably use this when I pull my motor as part of the conversion...

[vitaminZ]

Noob question but whats a AIV?..and i thought the filter sits under the nose panel?

[z32partsmo]

Many of us have asked but noone has given good answer. WHAT IS AN AIV?WHAT IS ITS PURPOSE?WHAT IS GAINED BY REMOVING THEM BESIDES WEIGHT LOSE?

[zxFarside]

I don't think they did anything at all. They are in 1990-1993 i think, then they stopped putting them in. Its just one of those wtf parts.

[DCaff300ZX]

What- Air Injection Valves (AIV), they are there for emissions purposes and allow a small amount of air into the exhaust to improve emissions.

Why Remove- They are relatively unnecessary and often have age failures such as broken hoses or vacuum issues, another problem is a gurgling sound. Also, once most of us have modified their exhaust system the AIV system serves no purpose and is definitely just added weight and potential problem area.

[Slizz]

could i put a bolt into my exhaust for now? My car is down for a month or so while i save up for parts to fix her. So im trying to do most of the free mods.. will bolts work until i get downpipes?

[t.mcginley.jr]

This has all been covered wayyyyyyy long ago:

http://s95014253.onlinehome.us/63104/137858.html

In short, the AIV system helps keep the cats cooler and thus they work more efficiently, at least in theory. I've kept mine on and I still failed emission inspection in NJ. It probably doesn't make a difference with or without them. In addition, after 1992 Nissan themselves got rid of the AIV system on all Z's.

[Z-owned]

This has all been covered wayyyyyyy long ago:

http://s95014253.onlinehome.us/63104/137858.html

In short, the AIV system helps keep the cats cooler and thus they work more efficiently, at least in theory. I've kept mine on and I still failed emission inspection in NJ. It probably doesn't make a difference with or without them. In addition, after 1992 Nissan themselves got rid of the AIV system on all Z's.

This was posted in 2010......And regardless a well written how to is always welcome regardless of whether someone else has posted one or not.

[t.mcginley.jr]

My bad, I should've been more specific I definitely wasn't trying to blast the OP for making this how-to! That was more in reference to the replies about what the AIV system is/does, etc. Mainly in reply to this post:

Many of us have asked but noone has given good answer.
WHAT IS AN AIV?
WHAT IS ITS PURPOSE?
WHAT IS GAINED BY REMOVING THEM BESIDES WEIGHT LOSE?

Sorry about that!