Rotary Car Club - Charging Problem and BAC question.

Rotary Car Club (https://rotarycarclub.com/index.php)

- RX-7 2nd Gen Specific (1986-92) (https://rotarycarclub.com/forumdisplay.php?f=37)

- - Charging Problem and BAC question. (https://rotarycarclub.com/showthread.php?t=1619)

Charging Problem and BAC question.

The car in question is an 88 SE. If im driving and I turn the lights on the battery gauge dips way down and the car surges back looses power a bit...you can feel it. It also does this when I run the AC. If I tap the breaks the gauge bounces and the dash lights dim along with it. If I leave it running and I turn the AC on,the engine will die. I know the alternator is good and the battery came out of my truck so it should be good. It will be checked tomorrow. Does this sound like a battery problem? Shouldnt there be a screw to adjust the idle on the side of the BAC? My TII had one, this one doesnt. The 86 base parts car I have doesnt have one either. Am I missing something? Thanks in advance guys.
Jeremy

I would:

-Check all cables for corrosion and pliability.
-Check all grounds for clean surfaces. Add grounds if necessary.
-IF the battery is too low, or has an internal short, it will draw power from the charging system. Just an FYI.

Check these things first, then get back to us.

~DJ

There's no idle adjustment on the BAC on N/A's (at least S4's).

How did you check your alternator/battery? Make sure the alternator is putting out at least 13.5v at any/all speeds.

Also, don't add new grounds, it's just extra wires. The stock grounds have lasted up until now, so they're more than adequate. Clean the factory grounds, replace the bolts, tap/drill the bolt hole out.

Quote:

Originally Posted by My5ABaby (Post 16059)

Had it checked at O reilly.

Ok, they're useless. Do it this way:
http://howto.globalvicinity.com/gv_w...i=92&co=1&vi=1

Ok thanks a bunch man,one other thing....how do I adjust my idle then?

There's a screw on top of the throttle body. It may or may not have a rubber cap over it. You turn that screw to adjust the idle (I forget which way does what). However, before turning the screw you need to jumper the initial set coupler which is a green two prong plug between the drivers side fender and battery OR just unplug the BAC.

Here's some info from my main man HAILERS over on the rx7club:

Quote:

Here's the deal. The BAC is supposed to compensate for loads. True enough. BUT, it wasn't ever meant to do the whole job of maintaining an idle. With the initial set couple installed, the engine should be idling *close* to 750 rpm. When you install the initial set coupler it puts the BAC's duty cycle at a set value that won't change as you fiddle with idle screws etc.

IF you fully heat up a engine, then install that coupler, the engine should idle close to 750rpm(repeating myself). IF it does not, then you need to adjust the idle using that screw and whatever else is availabe. Make sure the timing is set with a timing light first.

The idea is, if the idle is approx 750rpm with the coupler in, then when the coupler is removed, the BAC won't have to work is ass off holding the 750rpm idle even when a load is put on the engine later.

Personally I pull the BAC's electrical plug off when setting the idle. Easier.

And let it be known, that if the rpms are in the 800rpm plus range, the bac's air screw (turbo cars) or the dynamic chamber screw (non turbo) are not going to have any effect on the idle speed at all...hardly.

I've never been a bit shy about using the variable resistor on a series four car, to adjust an idle speed.

BAC'S are easy to check to see if they are working. Listen for the hmmmm of then cycling. Turn the key on and listen. It normally will be puttering away.

cool deal man....thanks. And yea, hailers knows his shhtuff. :icon_tup: