I recently got my dream car...a 1994 RX-7 TT. I bought it in Texas and drove it home to mid. tennessee, about 900 miles. I have not had any serious problems with the car as it has performed flawlessly since I bought it. I do have a concern about an engine noise. It sounds like detonation and usually only occurs at idle and winding down of the engine...also sometimes while the engine is winding down it sounds like a loose washer on a bolt type of deal, I dont know what it is though or if I should be concerned. The car has 89000 miles on it with a new engine and turbos that have 5000 miles on them. Also, once today in first gear the turbo didnt kick in, and after the first mile or so it was ok (this was after the car had been sitting in the sun for about 2 hours, its 90 or so here).

The engine runs strong and I am pretty sure it is running like it should...but I am concerned about the detonation problem. Is there an anti-detonation device I can get or any solutions you guys have found?

Any comments suggestions or solutions you guys have would be much appreciated.

 

the anti-detonation device is currently being tested by KDR but not officially done. Your turbo shouldn't be kicking in on 1st gear, it should be spooling then kick in on your 2nd gear depending on how hard you're pushing it. About the sound? I have no clue for that one...

 

Maybe I need to change the oil...of course a good idea since I dont know when the last oil change was. the detonation (popping) sound isnt that bad, I just dont want it to do it...of course I dont, is there anything I can do or shouldnt do? Is this a common problem among 3rd gens?

 

what do you mean the turbo should not kick in in 1st gear? You should be able to get boost in every gear. In 1st gear if you dont get atleast 7-8 lbs you have some problem.

 

It's highly unlikely that you're seeing detonation at idle......poke around the engine bay while a buddy revs the motor for you. It's prolly a loose piece o metal.

 

 

The sound is definatley coming from the engine...it sounds like popcorn popping while im idling...maybe its not detonation...but its something...I only hear it at idle...maybe I could record it and let you listen to it? (its a soft popping...not like when your kickin it hard through a tunnel.) It may be completly normal...but I dont know.

 

when I swap out my regular catback with a hollow catback I always hear a "Tick-tick-tick-tick" with about 1 second in between ticks. I never hear it on my HKS exhaust but my straight through I hear it at idle.

Here is a hint and dont tell anyone (You will not detonate at idle).

 

It is sort of like your tick-tick...but not at regular intervals like every second or so...its irregular but probly the same thing...so I take it this is normal...or ok for the engine?

haha...thanks for the hint. I am new to the rotary but I know mostly how everything works but this is my first actual car.

 

it sounds like a misfire to me

you don't generally hear detontion you just know it happened after you blew the motor...especially at idle haha I doubt you are detonating unless you have a map in a pfc from like a honda or something.

when you are cruising at a constant speed for a while do you get the same sound?

 

I agree with rich, its probably loose metal or something. You're not detonating at idle. It would stall if the conditions were even close to right for detonation. Try getting a broom handle or some kind of wooden dowel and press it against the block. If its a vibration/sound from inside the engine that will tell you where and when its occuring. If its noticable its probably not normal.

 

I dont get the sound when I am crusing at a constant speed...but I might just not be able to hear it. It might also be the exhaust or somewhere between the engine and end of the exhaust...I dont hear it coming out of the end of the exhaust or from the engine bay...it might be coming from the down pipe or something.

 

It actually sounds like exhaust gas is collecting somewhere in the exhaust pipe and being let out through a hole when it has enough pressure...or something like that...

 

ohhh I think I know what it is now

it's probably the stock cat making noise
A heatshield or piece of metal is probably lose on it or maybe it's on the inside all i know is that I took mine off and the FU**CKing sound stoped haha.
mine had 70k when I took that heavy POS off
it was driving me crazy at idle is when I could hear it!!

 

Mine was just when I let off the throttle, and it's most likely a clogged pre-cat and or main-cat... Mine's in the main cause I allready replaced the pre with a DP... and this weekend the main will go and Midpipe will go on...

I mean.... I'll replace it with the proper exhaust equipment Officer !