fuel issue i think

[zachsearcy]

I have an all stock 92 240sx. it has always leaked a little oil. checked oil yesterday and it was pretty low. i drove to the gas station and put in 2 quarts. this got it up to a little above the halfway point. i start the car up and it idles really rough. i drive it about 50 yards and it runs rough. i stop the car and inspect. some black smoke coming from exhaust. car starts to idle ok, but car will not go above 2500 rpms. seems like too much fuel or not enough. car kinda gets violent when i get up to 2500 rpms. im thinking the 2 quarts of oil is just a freak occurence...doesnt seem like an oil issue. it had a leaky head gasket that was replaced less than a year ago and i see now leaks or breaks in it. i replaced the spark plugs, wires, fuel filter, and added some fuel system cleaner for the hell of it. now just runs bad better. no smoke...smoke only happened at the very beginning of issue. the engine was replaced about a year ago from a used 95 240....i remember the guy that put engine in saying timing belt or timing chain looked a little rough. perhaps the 2500 rpm thing is a timing issue? what should i do next? wouldnt have any clue on how to fix timing chain. could do fuel injectors next.

[zachsearcy]

the more im researching, the more i think it is the timing chain. i think that is outside of my mechanical ability. any shadetree mechanics near knoxville, TN that I could throw some money at?

[zachsearcy]

Ok, so i took it to a real auto repair shop. They told me it was the mass air flow connection. They said it was loose and reconnected it. However, when I went to go start my car, there is an entirely new set of problems. At first the car wouldnt start. The car is 20 years old...every once in a while it wont turn over. I usually just wait a couple seconds and it fires up just fine. The guys come out to look at it, and start messing with the clutch switch. They fix that, but now there is just tons of grey/white smoke coming out of exhaust. The car has never done this. There was black smoke for a brief moment with the original issue (see first post), but never this kind of smoke. I ask the mechanic about it and he just says "its tired and she runs rough". I inquire further about if theres anything I could watch out for with it and he says "just watch the oil levels". I sputter my way back home...car even dies a few times on the road...like its trying to stay alive but just sputters from idle to off. I get home and check the oil...waaaayy too much oil...a little over the top mark. Now, I checked the oil a few days ago and it was about it the middle...see no reason why these guys would add oil to the car. I drain about a quart-quart 1/2 of oil and start her back up but the problem persists. Lots of smoke, and is just running poorly. I dont know if sense it was late in the day and the guys were just trying to get home and didnt care or what. They have a pretty good reputation around town from what I understand...pretty nice place actually. The original issue is fixed, and have learned that its called the "limp issue". Any idea what they could have done to start all this new trouble?

[walperstyle]

White smoke = coolant (probably head gasket, or coolant leaking in near the part where the intake meets the head, there is also a coolant neck there)

Blue smoke = oil, as in its burning oil, not leaking
black smoke = usually fuel, or all of the above.

Run a compression check before you start pulling the head apart.