I have a 93 fd and it's not making the power it should I race one of my friend's Civic Si with only intake and we were head to head from stop to around 60. The symptons are making only 5 lb of boost at around 4500 rpm, it will puff out black smoke from exhalst once in a while, and I only get around 13 mile/gallon. The weird part is that the ac would turn on by itself sometimes and when it turns on while I am idling the rpm drop really low and make the car vibrate and sometimes the engine would just die from that. I have no mod except k&n air filter. The body shop just told me that I need a new engine, but I think it is not that bad yet. Anybody know what is causing all this problem in my car please tell so I know for sure if I need a new engine thanks for all the help

 

what is your vaccuum at idle? It should be at least 15-16in/hg to show a good healthy motor. do a compression test to be abosolutely sure.

Black smoke means unburnt fuel mainly. You shouldn't be getting beat by a civic even if you only have 5psi. 13mi/gallon isn't that bad if you are modded etc. What is your boost pattern? you said 5psi at 4500 but that is transition, what about before and after transition? Check the vaccume hoses espeically wastegate and pre-control to see what's going on with the turbo. And stop racing civics until this is fixed!

 

The BODY shop told you you need a new engine?

If you still have the stock precat, I'm 99% sure that a downpipe will fix your low boost problem.

 

You should stomp the SI without even trying. I don't think your motor is bad. You would probably be blowing more smoke, and your idle would be bad all the time. Do you have a boost gauge? If so, what vacuum are you making at idle? That will be a good indicator.
At first, I thought it might be your turbos, but now I don't think so. A bad turbo wouldn't affect your idle. Check your ignition system (plugs,wires,coil etc.).
Good luck

 

What's your boost pattern? The car stalling with the ac on sounds like an electrical problem. Get you alternator tested at autozone for free.

 

Im guessing that your car dies when the AC is on and your car is in gear. If you put it in nuetral the car idles fine. This is the symptom of a bad clutch switch and is not uncommon. The clutch switch is fairly easy to replace. Do a search I believe the part number was listed in a earlier thread. As for the low power sounds like you have a vacum leak somewhere. If you haavnt done vacuum hose job yet, you are in for a treat, If you have its time to check your vacum connections also a treat. If your turbos were bad you should be blowing out bluish white smoke, black smoke is unburnt fuel wich means you are running rich. This is probably due to the fact that you are not getting enough boost.

 

is it an auto or 5 speed?

Nick