Hey everyone, my '85 GSL has begun to make a strange metallic popping sound every time I rev it hard and shift. Rev past 4K, shift into 2nd, POP, rev past 4K shift into 3rd, POP...you get it. It isn't that loud or deep, just small metallic pops after most (not all) shifts. Any help with this issue would be great, as I'm just scratching my head

Thanks , Alexi

 

detonation comes to mind.

 

one more thing, its not coming from the engine compartment, but rather underneath or in the rear

 

Probably some twentysomething bushings on your axle's locating arms. Find some energy suspension bushings, drop the axle one afternoon, and start swappin'.

 

Completely normal. Most RX-7's pop either when you shift, or decelerating. Hell, some even shoot a flame when you shift at high RPM.

 

Are you sure its not in the exhaust?

~T.J.

PS -
Thats revving it hard?

 

thanks a lot for all the responses on this lovely saturday evening. By getting on it hard I mean pressing the gas down to the floor or close to it It may be coming from the exhaust i suppose; it just sounds a little too faint; not deep enough bang to be exhaust to my ears, but can't be sure. The interesting thing is it started just recently, so if it is the exhaust I guess it would just be a hole?

thanks again, alexi

 

sounds like a driveshaft u joint
maybe?

 

My bet is that you're hearing pops in the exhaust system. The cause could be a hole, but unless you've noticed a noise increase, I wouldn't put too much stock in that theory. I think it's more likely that there's a problem with the emissions controls. I'm not familiar with the FB controls, but it could be the shutter valve. My '82 popped on upshift and downshift before I plugged the hose that actuates the shutter valve, so there's something to check.

As an aside, it's kinda dissapointing to drive my SA sometimes, because it doesn't make any pops or backfires, even under hard driving. My '82 was good for a flame or two, plus the usual pops under hard driving.