arutha

iTrader: (2)

OK. I bought my RX7 a few weeks ago and there is a noise coming from the airpump.(I have read tons of posts) It is not a loud screeching noise like a bad airpump. (I have heard a bad one) It happens normally between 2300ish RPM and up to 3800ish RPM. I know the clutch should disengage at 3200ish. Not sure if it is or not. I hear a metal sounding whine. It does not happen all the time. Normally under slight throttle and sometimes if I get off of the throttle it will make the noise briefly.

When I unplug the airpump the noise goes away.(it never makes the noise at idle though) I have swapped the airpump for another (roughly 40k on it) and it does the exact same thing. I have loosened the belt and it still happens. I had the alternator checked out just to be safe and it is fine. I see no problems with the hoses. (it does blow/suck air) The fact that it occurs above 3200 RPM also is making me think it might not be the airpump causing it. Do these things make strange noises normally? Maybe I am being finicky and just need to turn up my CD player.

ANY help would be great.
Thanks

majikeye

how old is your belt? do you have an aftermarket intake? one of these two things may have something to do with your noise. mine started making noise after i replaced my intake. it sounds like a hollow "moo" like that of a dying cow.


also, if you have a down pipe and mid pipe you could just remove the airpump altogether.


just a thought. hope it helps...

arutha

iTrader: (2)

Sorry about that. I have stock everything except a downpipe but it was doing this before that. Belt doesn't look bad. Didn't see any cracks or anything. I do wonder if the belt could still be too tight. When I put on the airpump I pulled up on it pretty hard and then tightened the bolt. I didn't pry up on it with anything. Just using my hand. I have the alternator tension thing just a turn tighter than loose. I can move the belt pretty much the same as the other one. I don't have one of those tension things to see what it is really at but I can't get the belts to squeal yet either. Not that I want them to but at least then I would know it is too loose.

911GT2

Does it sound like it's mooing? Airpumps do that when aftermarket intakes are installed, maybe yours is doing it without.

arutha

iTrader: (2)

I wouldn't call it mooing. To me it sounds very much like a metal to metal buzz. The higher the RPMs the faster the buzz. And of course the sound goes in and out. Sometimes it will go from around 2600 to 3200 and then start back for a few seconds around 3800. It isn't reallly loud but it is noticable. At first I thought it was a shield or something vibrating against something else and that it would vibrate faster as I increase RPMs but that wasn't it. If I unplug the blasted airpump the noise stops.

Currently I am becoming low on money to purchase more "upgrades" (I have a wife) Plus we do have emissions in this county which I failed at idle but passed with flying colours at 2500 RPMs. But that is another topic.

arutha

iTrader: (2)

I do have another question related to this. Someone mentioned in an older post that if you have a tuneable ecu that you can lean out the fuel mixture at lower RPMs and it should "save" your cat. Will this also fix the emissions problem? No where I take this is going to do a visual inspection for an airpump. Will the PFC or something similiar help? I would be more tempted to just buy that and get it tuned as opposed to fixing the airpump as long as it would pass the sniffer.

arutha

iTrader: (2)

Just wanted to mention my solution to this problem. Hate to bring back old posts but someone PMed me about it and I thought I should mention the solution in case anyone else has similar problems

The problem ended up being the ACV check valve. It just wasn't seated correctly.

911GT2

Good to know!

alwan16

same thing happened to me...the little metal 1" circular check valve going to the port air injection had slipped down a little bit. anytime i went over 1500 rpms it would almost make a whistling metal on metal sound. glad you found it.