I have recently purchased a 93 R1 with all the usual bolt on stuff: Lg Intercooler, Pulleys,Downpipe, Catback,M2 ECU, MaxdaComp Radiator, Elim AST, cold air box. When I spin the car to 7000 RPM the car starts popping like an automatic weapon (only louder) the guy I bougt the car from told me this was the rev limiter. Since the car redlines at 8000, and from what I understand the M2 ECU should eliminate the rev limiter, and stock is set at 8200, I feel there must be some problem causing this. I origionally suspected the M2 ECU, but I spoke with Brain and Brett at M2 and they assured me that thier ECU mod has never failed and that only occationally have they had one not work altogether and that was always from the beginning, never a failure later. Does anybody have any opinions? The car also seems to run rather rich. ANy input would be appreciated. Thanks for your time.
Robby

 

A/F is out of wack. Get your car dyno'd. Sounds like your running too rich.

 

A sincere thanks to all of those who have posted to this thread. Here's a litle more info. I have changed out the spark plugs, to no avail. Although the powerband was a bit smoother up to the problem range (again 7000 RPM) but did nothing whatsoever to improve the popping. The problem is very "switch-ish' meaning that it is distinctly at 7000 RPM in any gear, keeping me in the mindset that it is electronically controlled or triggered. It's feels like the ignition is just shutting down, although I wouldn't rule out the possibility that it could be fuel related. It's just such a dramatic activity at exactly 7000 RPM that it seems electronic. Thanks again for time guys..
Robby