I've had this strange problem whenever I go WOT in my TII. At about 4k rpm's I hear this strange tapping sound coming from the engine. When I first heard this I panicked thinking it was detonation, however, it's done this several times now and I have yet to lose an apex seal. It doesn't do this everytime, and it only taps once quite noticeably. I have no idea what it could be and I'm just hoping someone has any idea. I'm sure it's not detonation because the car is actually running quite rich. Any suggestions will be greatly appreciated.

 

Just because your car is running rich, does not mean there is no detonation. Seeing how there are no valves or such under the hood, I could only believe it would be detonation. Check you timing, and look at your spark plugs. Search online for reading spark plugs, and take a CLOSE look at them. I't amazing how much those little suckers will tell you. You also could consider looking at the quality of your fuel, you are in a higher altitude, so that could also assist in detonation. Try to put some HIGH octane fuel in there, and see if it goes away. I'M NOT SAYING you should start running high octane fuel all the time. I would rather troubleshoot the issue, and THEN fix the problem.

Just my .02
Jesse

 

Thanks. I'll try getting some higher octane in there, but the highest at the pump is 91 so that will be the last test. I'll try checking the plugs and ignition. Any other ideas are still appreciated.

 

Well I got some good octane booster (not the cheap .1 octane stuff) since I figured it couldn't hurt and ran the car somewhat hard. At first the tapping actually got worse and the e-brake light kept flashing along with it, but then it went away completely until I stopped. When I let the car idle the tapping noise started, but this time I had the opportunity to pop the hood and listen. The sound was coming from the dash instead of the engine. I knew it couldn't be detonation since the motor hadn't thrown an apex seal, that or I have a particularly tough rotary. My question now is what could be making such a loud tapping noise in the dash? It's obviously an electrical problem and it's somehow tied to being at full boost at 4000 rpm's so I have no clue what it could be. Maybe a bad ground? I'm running 10psi and that's only because I can't lower the boost any further with the 2.5" dp.

 

Well I still haven't solved the problem. Higher octane doesn't help, and it turns out what I thought was the original problem is just a new problem on it's own. Could the tapping noise from the motor possibly be backfire somehow burning early? I think there's a slight leak in the exhaust just after the pre-cat downpipe, could that be part of the problem? Has anyone heard of a rotary that survives constant knocking problems?