tapping noise emitting from the air intake chamber - Toyota Nation Forum : Toyota Car and Truck Forums

dreadloxxx · 10-12-2004, 10:14 AM

Hello all. I have a 1988 Supra, 5-speed, NA. I have recently done a top end rebuild. It was running fine for approximately 7 weeks and now I am experiencing a tapping noise that can be felt at the air intake chamber and you can also feel the vibration on the shifter and sometimes the clutch pedal. The car drives fine, but the noise is very annoying. You can hear it at idle and also while driving. If anyone out there has knowledge of what the problem might be, it would be greatly appreciated to know what ails my 7M-GE. Thanks.

Jeeves · 10-12-2004, 07:12 PM

Does it increase with RPM's? Get Louder? anything?

dreadloxxx · 10-14-2004, 09:16 AM

Thanks for your quick reply. The sound is relatively the same no matter what RPM. At start up, the sound is sometimes absent. When I started the car the other morning it was running smoothly. I immediately turned the a/c on and there was the noise. When I turned the a/c off, the noise stopped until the car got up to operating temperature. When the car gets to operating temperature, the sound is more pronounced. I have placed EGR block offs on the engine. Could that contribute to the problem?

Jeeves · 10-15-2004, 01:50 AM

Not really. I've got JDM (Literally, Came with my Japanese motor) EGR Block off plates and they cause no suck thing.

Can you guess the frequency of the noise if it's about the same all the time? twice a second? less/more?

Also, what type of tapping is it? Harsh? Metal on Metal? Can you compare it to anything I could recreate (i.e. "Think of tapping a key on your car hood 5 times a second")?

dreadloxxx · 10-15-2004, 02:22 PM

The frequency of the noise is the same whether driving or sitting idle. It is constant now. I would estimate that the sound is about 5 taps per second. It sounds almost like you are tapping on wood. The car drives fine if you are driving regular or running it at higher RPM's. I hope this bit of information assists you in diagnosing the problem. Thanks again.

dreadloxxx · 10-21-2004, 01:45 PM

Cancel the diagnosis. The problem has been solved. The crankshaft pulley bolt had started to work itself loose. Torqued the bolt to specs and the car is as good as new.