Remember my AC problem with the car (1993 Civic Si with 215k miles) almost stalling. Well now I noticed that if I keep the fan on #1 the car sits nice. When I select #2 the car's rpms drop a little. On #3 the car starts to stutter and rpms drop really low. On #4 the whole car shakes and feels like it's about to stall. What's going on here? Alternator going? Something is not charging right?

Also at the last autocross my 1st run my car's temp was fine. But runs 2, 3, & 4 the temp gauge would shoot up after driving the car hard in the first 10 seconds. I saw the temp gauge almost touch red every run. I bled the coolant for almost 30-40 minutes, refilling it when the themorstat opened up. What's going on here? Water pump? Timing belt? Accessory belts?

Also noticed the rpms climbed when I pumped the brakes at the start line and then return to normal.

I think my car is cursed

 

weird....I do know that your rpm's are suppose to drop some when you turn your a/c on n such (you prolly already knew that)....but sounds like something is putting strain on your motor causing it to stall

idk what to tell you on the whole overheating issue..... are your fans kicking on?

 

How modified is the vehicle?

 

It sounds to me like alternator issues - I've experience very similar symptoms with my '92 EX (also D16Z6) but they aren't as quite as bad.

I'm not sure how much voltage the alt on our cars is supposed to put out at idle (when warm) so I can't say for sure how much you should "notice" the alternator when you put more electrical strain on it.
However, you shouldn't notice a big difference in idle depending on the fan speed.

On mine I can hold the brake and in most cases the idle will drop a little and when I let off it will return to normal. If I pump it, as you did, the rpms will spike just a little and then return.

I've found that if I remove most of my taillight bulbs w/ 2 remaining I don't get a dip in rpms when I hold the brake but, if I remember correctly, I can still get the spike by pumping the pedal which I'm assuming is due to the ABS pump :hsdunno:

Anyway, it's possible that the bearings are bad/going bad on both of our alternators or maybe they simply need a rebuild so they are putting out the proper voltage and so dont have to work as hard to keep the engine running and battery charged. I don't know enough to say for sure.

On my car I can tell whether the alt is really working or not while shifting because the revs drop a lot faster when it is.
My car also has that high-pitched whine sometimes and I know it's the alt because when I drove the car on a 1/2 dead battery the sound was super loud and non-stop. Plus the car drove like crap and the revs dropped super fast when shifting, even worse than what I'm used to with the A/C on.


I got a rebuilt Denso for $160 total and would have installed it already but it arrived late and now due to my schedule/weather (oh and I'm lazy) I've yet to get around to it.

I hope this helps, I'm no mechanic and I can't say for sure that you have the same problem as I do but I am 100% convinced that my problem is the alternator (I wouldn't have paid $160 if I had doubts) and you seem to have similar symptoms.

 

Not much yet since stilll working on the bugs: intake, exhaust. Just replaced the radiator, cap, hoses, and thermostat this year.

Probably needs a new alternator, water pump and timing belt, since no paperwork came with the car.

 

see if the waterpump is leaking coolant.