Originally Posted by sicminded

Hi all,

First off, i would like to proudly say that for the first time of owning a RX-7, I actually worked on my own car today. I haven't even ever performed a single oil change, on this car atleast. And today, I tackled the removal and installation of an airpump. It did take about 3-4 hours though.

The situation:

The reason I installed a new (well used, bought from a fellow forum member) airpump is because, obviously, the old one needed to be replaced. The symptoms that pointed me to this is that upon reving the car to ~3k rpms, and when the rpm's go down, the airpump pully would lock up. Only beginning to turn once again at idle. When I mean locked up, I can see the pully and magnetic clutch seize and stop, and it would make a weird sound which is from the friction of the belts continuing to run over the seized pully. I told my symptoms to my mechanic, and he suggested that I look into replacing the airpump.

So after replacing the airpump, it seemed like it was working. Upon reving the car to ~3k rpms, the clutch/pully does not seize up until idle anymore.

But I'm still concerned with a few things. Coming down from reving at ~3k rpms, it locks up only for a split second, you can see the magnetic clutch stop and hear it click, and resumes rotation as the revs come down below 3k rpms. Normal to be able to see and hear it engage/disengage for that split second?

The other thing I'm noticing which I'm not sure is normal is that when reving to ~2.5k rpms, it makes weird noises, almost the same noise as my original symptom (the reason I replaced the airpump in the first place). But when having someone rev the car to ~2.5k rpms, I'm looking at the pully, it's not locking up at this rpm, but i'm still hearing noises. It's like a fluttering vibrating sound, not metal to metal (i think), and a little wooshing of air, which i think is normal. I'm more concerned with the fluttering vibrating sound, it makes the noise when the revs reach ~2.5k, not so much when it comes down. Reving past 2.5k rpms and above, it doesn't make the noise, only at or slightly below 2.5k rpms. I hope it's not another disfunctional airpump.

Let me know if you guys have any ideas. Thanks for reading,
Chris

Originally Posted by atihun

Some noises are normal; people usually hear a moo- fart sound from the airpump to the stock airbox.

Check your belt / bolts if there is physical vibrations, also it could just be when it's pulling in air.

As for the clicking on 3k, that's normal. The airpump clutch disengages so it is no longer pushing air into the ACV. Any air leaks?

Or you got a duck in the intake .