OC94Rx7

Recently, My car has developed a high pitch squealing sound. The general area is behind the air pump, between the black pressure chamber and the intake manifold. The sound will start after a short or long run, but not if I just bring the car up to operating temp's sitting in the driveway. Again, the sound is like a bad bearing and more simular to listening to someone using an old mnilitary Morse code but with a much higher pitch.

History -

Last month I replaced all the vacuum hoses & polished my intake manifold. The sound is difficult to hear while driving, so it may have started after I finished the hoses job? not sure. I first noticed the sound after a short run and letting the turbo cool down. It also makes a sound simular to a belt squealing after you shut down the motor and you get that fading off squeal sound when the motor stops.

Things I've done -

I did a search under - " strange noises, squealing, bad air pump, pressure chamber, intake manifold, vacuum hoses, boost leaks and belts.

1st - I checked the air pump belt tension. After adjusting the belt to what I felt was correct. The sound continued during start-up (motor was still warm from earlier run) When the idle dropped to 740. The sound faded and then stopped.I was a happy camper. Until, the next day the sound returned. Both belts had been changed in the last 1000 miles.

2nd - I checked the air pump. Disconnected the air hose and it pulls air great. Pushed the throttle to 3000 rpm and the magnetic clutch stopped. Disconnected the electric connector and the sonund continued. I then used a plastic tube and tried to locate the sound better. A slight sound from the rear of the air pump. continuing over tbetween the pressure chamber and intake manilod the sound increased.

3rd - even though the sound is more metal than air. I checked the pressure chamber for leaks. Removed a vacuum hose and it released a air pressure sound. So, thats ok.

4th - I was thinking about checking the y-pipe connector hose. But, my car has 37,000 plus miles and I don't have a primary or secondary boost problem. Related mod's are : M2 intake, M2 hard intake pipes, M2 downpipe and Racing Beat exhaust. Boost is 11-9-10.5/11.

Any suggestions of what my next steps might be? Sorry for the long post. Just wanted to follow where I have been.

Thanks - hope to here back from some of you.
Oliver

Wade

iTrader: (1)

Check your acv. There is a metal disc behind it that sometimes gets loose or slightly crooked and it will make a similar sound. Should stop around 3000 RPM range if that is it.

Wade

OC94Rx7

Rikki - Thanks for the suggestion. The only thing is. It's not coming from that area. I appreciate the help!

Wade - I was crossing my fingers, that the problem would not be under the manifold. I think the ACV is a good place to start. Thanks for your help!. I did a search and found that it can make a simular sound as I discribed and it's in the general area.

When I replaced my vacuum hoses. I was able to remove the 2 lower vacuum hoses without having to remove the AVC. When you say the disc can get loose or slightly crooked. This can only happen if you remove the ACV and reinstall it? Or does this just happen after time and wear?

Also, while re-attaching the 2 vacuum hoses to the Soleniod valve ( turbo control). I was concerned they might be pinched because of the sharp angle in the bend. Do you think it is possible that could be a related problem?

it's getting late here. Will have to wait until tomarrow before I can dive into the manifold again..

Thanks!

RX-8

iTrader: (6)

Sorry had to bring this back from the grave. I have the exact same symptoms after my intake manifold was taken off. Does anyone know what the cure is? OC94Rx7?

dubulup

I have a morse code noise sometimes too...I was thinking maybe the water pump?

Leaky one replaced, then Russians were trying to contact me via the non-leaky one...

NewbernD

iTrader: (1)

I thought I had squeaky belts or a bad idler wheel bushing for a while until I finally pulled the belts off.. and then I turned the water pump pulley and heard my squealing noise. It would come and go and sounded just like a squeaky belt, but was definitely the pump.

RX-8

iTrader: (6)

The problem I have is exactly like oc94rx7's. The noise came about after I took off my intake manifold. Once i put it back on a loud squealing noise developed at idle. Haven't driven my car since (that was 4 months ago). I was wondering what he did to the ACV that might have cured the problem. If that was the cure. Oc ya out there??