Alright, this is going to be long, so beware...

I have a 1993 240sx coupe. Original KA with approx. 170k miles. Been having some hesitation issues for the past three years.

Back in the day it would hesitate for a split second while accelerating hard, around 3500rpm, in any gear. I replaced the spark plugs and wires, fuel filter, distributor cap, removed AIV and AGR, cleaned TB and IACV and checked MAF. According to Chilton's, my MAF voltage reading was way off. I assumed it was a bad MAF, so I bought used one from a friend and tried it out. Problem went away for about a week, then returned even greater. Eventually I switched back to my original MAF. I checked injectors (all 4 good) and compression (170, 168, 170, 169). Also gutted the cat. Problem still remained.

Now three years and 50k miles later, it's almost undriveable. Engine hesitates, bucks, and almost dies when cold (goes from about 30mph down to around 5mph). It has no power -- I got passed by a base model Caravan entering a freeway - I had it floored. Engine still hesitates bad at will. Sometimes it won't hesitate or buck, just seem like it has a total of 80 monkeypower and less torque than that! It also has a thing for dieing when coming to stop (clutch depressed).

Fuel consumptiopn is up (probably avg 200-225 mpt) and the problem remains. I also think the rings may be shot because it smokes (like every other Civic out there) and smells even worse. Haven't checked compression again.

On a lighter note, it's been run completely out of oil once, and overheated badly once (immediately pull over once I noticed steam coming out from under hood - coolant was boiling rapidly). The windshield is cracked all to hell, sunroof doesn't work right, it has half the seatbelts it's supposed to (which don't even work), e-brake light in eternally on, gas door cable is broken (held shut with an allen wrench), trunk doesn't stay open, front passenger shock is blown (won't compress at all, headlight are aimed way off (highbeams don't even work), interior is stripped and *most* of the sound deadening removed, seat is torn, power steering doesn't work, a/c is charged but compressor is fragged, cruise doesn't work.

All that and the fucking HUD still works!!!!!!!!!!!! RRRRRRrrrrr damn thing has a mind of its own!!

Anybody? Anyone at all???

 

First thing is first, running out of oil and overheating are bad. First check your oil and coolant to make sure it's not full of milkshake (oil and water mixed looks like chocholate milk). Next thing to do is go under the hood and rev the motor. If you hear a noticable "clack" sound, then the no-oil thing killed your bearings. I've heard of KA's running on no oil and being fine. If all things check out, then you can start diagnosis.

The smoking, smellyness, bad mileage, bucking, etc. are probaly all related. Sounds like you have an awesome vacuum leak somewhere. Just check all of the couplings to make sure that they are tight and not cracked. This includes hoses going to the valve cover and idle valve, too. Also, don't forget the intake cannister hiding on the passenger side of the radiator, underneath the intake pipe. If that's not it, verify that your fuel pressure regulator is hooked up correctly.

If that's not it, check the following:
- coolant temp sensor
- cap, rotor, wires, plugs
- leaky injectors

All of the rest of your problems can be solved with your check book. Also, put down the Chilton's and get a the FSM from www.zeroyon.com.

Thank you, drive through.

 

also, with diagnosing the vacuum leaks, if you think its coming from a certian area, spray carb./ throttle body cleaner in the area on the hoses, if it evens out, you found your leak.

 

Never let your mom drive your car. I found that out the hard way.