My 1988 Mazda RX-7 Turbo II has this problem, it will almost never crank fast because the battery is only at like 8.87 volts, and sometimes the car will fall on its face just while boost is pushing me into my seat, then it comes back on and carries me some times up to redline. Sometimes it hesitates very bad and I can hear something popping sounds like its coming through the exhaust. Alot of times when I press the gas it just stalls out, or stalls to like 500 rpms then restarts (my car is idling at 1800 rpms, stuck throttle linkage). Sometimes it runs fine, it is an intermittant problem so I thought it could be a bad connection some where. Anyways I tested my battery at only 8.8 volts, and the alternator read 12 something but never up to 13 and this is with all accessories off. Please someone help me out, I ordered an alternator in case I need it. I want to autocross this car Saturday and don't have barely any time to get the car ready. Thanks alot, Zach

 

what mods if any do you have

 

a bomz intake filter, i just put it on and i think I might have the maf sensor on upside down. which side should be facing up the side with the black label? as seen in dDub's car. I do also have that high idle problem, and plenty of exhaust leaks. It was also overheating today so I took out the thermostat which solved that problem.

 

somebody help me out please, i just cleaned the battery terminals...they looked pretty bad before, i mean not corroded but they had this white looking rust on it or something so I scraped them to bare metal, now i'm going to take of the alternator charging wire and clean that connection, also while the interlcooler is off i'll try fixing my throttle linkage and flip my mass air flow sensor back over. I'm working at night time because I won't have much more time to work on it before the autocross.
thnx

 

I'm pretty sure I fixed it, I cleaned the terminals and removed and reinstalled the intercooler as well as the alternator charging wire terminal. I think it was the battery terminals. Without a thermostat the engine runs too cool and the heat doesn't work that well so I think i'm gonna put a geniune mazda thermostat in, but atleast it doesn't overheat. i did all this work at 11pm-1am.

 

I have the identical problem. I would suggest having the injectors cleaned. Try putting in some 2 stroke oil in the gas tank as well. Check the tps. The ignition probably isnt getting the juice it needs. Get a new battery. New plugs. Could be a bad fuel pump, fuel filter, fuel sock. Could be the BAC as well. Let me know how you fix it if you do please!