Engine shaking + Black smoke - ALOT!!

[FUNGC]

my car is a 1992 240sx with a KA24DE engine

ok long story short...

ive taken out my engine to clean out my engine bay, and give it a fresher look. now when i put everything back together, it started, but it shook alot! ive checked for spark on all 4 cylinders, and there is. so after some time i gave up and threw in another KA24DE with lower km's and it was guaranteed to work.

but almost the same thing is going on with this engine. it shakes, but not as much. as i rev it TONS of black smoke comes out and my exhaust smells like gas. it is running very rich.

all the parts are the same that were used on both engines (e.g mafs, intake, exhaust, etc.) only the engine and it's sensors are different

im guessing that either the mafs is faulty or the cat is clogged, or my ecu is just messed.

please give me some suggestions, as i want to drive my car again. thnx

curtis

[Black on Gold]

Im thinking your rings on the pistons are gone? I have the same thing with my Hatch

[FUNGC]

hmmm... i dont think soo... i used 2 different engine, and one was bought from a working coupe 240 that ran 500kms to the tank still.

[Black on Gold]

Hmm.. how are the motor mounts? That might be the shaking.

[FUNGC]

they are mint. no cracks, and not even broken. the first engine i put in shooked alot. this one still shakes but it doesnt shake as much as the first engine. both are running very rich.

i also smelt the engine oil of the first engine and it smelt like gas...

im pretty sure the rings arent gone on my engines cause it would have caused alot of blowby, and it would have burnt oil, which if irc that blue smoke is burning oil, and black smoke is running rich.

[Suicide.Veteran]

check to make sure a cylinder isnt flooded because of a stuck open injector. flodding in the cylinders can also put out a spark causing it to run rough. Maybe recheck timing? Check the plugs. does it reek of gasoline are they rich.

[FUNGC]

checked the plugs and they arent wet at all. they do smell like gas however. all cylinders are firing and im getting way more fuel than i should.

[Black on Gold]

Are you feeling like you get about 10mpg? Because thats how mine is acting right now. Got the exact same thing

[driftedsilvia]

it sounds to me likeone of your sensors is bad tps/maf. If you got a dvom(multimeter) l can tell you how to test all of them but if you dont i dont know.try just unppluging your tps that used to do the trick for my 92 and got me going til i had money to buy one...But im almos sure its your tps its very common for them to go o ut on 240s and 300s

[FUNGC]

yea i got a multimeter, and im leaning towards the mafs is busted. i did a search here and then most of the results were a bad mafs, and i did lend this mafs to a friend for a while and not sure what he did with it.

anyways how do you test if tha mafs or TPS sensors bad?

[driftedsilvia]

i can tell you what to do but i just dont remember wich color of wires to check but its the same principal for both. Ground your meter first(black lead to grounf) and then the +wire goes into one of 3 wires that connect to your tps or maf. youo have to pierce through the insulator of the wires with the engine on accelerate the car and you should see the voltage increase for both the tps/ mafs. just try all 3 wires til you se some action. one of the wires will have 5 and 12V steady THATS NOT THE ONE. USE THE ONE WHERE THE v Is CHANGING.on the tps once you find the signal wire wich is the one that changes with movement. leave the key on with the engine off. (when your check engine light is on) and turn the throttle really slow and watch the voltage inncrease as you open the tb it should go from li.e .2/4 to 4V with out any opens or gimpses i you see any skipps on your meter replace the tps. Same thing for the maf but for the maf your engine must be running, you know to meassure the air runnung through it its ok if yousee it go from 1-4v at once as long as you dont see OL on your meter in the process ot should be ok. If you cant figure it out let me know Ill look up wich wires your suppose to check but i think this should help. let me know if you got any more ?? or if my instruction sucked as ill try to explain everithing better....

[FUNGC]

yea that makes sense, now i just gotta jump start my car to test it

[FUNGC]

ok now i cleaned tha mafs and everything and i think its messed.

it runs even ****tier than before, and when i pull off my mafs it idles the way it should. nice and smooth. now once i put back my mafs, it just bogs down and then shakes a hell lot.

does this mean that my mafs is screwed?

[driftedsilvia]

where did you get the idea of cleaning the maf ?and how did you do it? that does not sound to good....If you plug it and the cars starts accting up theres like an 80% chance that its bad but its an expensive part you should fully test it before you go and buy a new one. Do you know how to measure resitance?I look for the specs so you can do it and be 100% sure......all you need its an ohmmeter

[FUNGC]

i got the idea of cleanning the mafs from this site. i searched all over nico and most said bad mafs and it does sorta sound like my symtoms. i cleaned it with sensor safe carb cleaner.

and parts up here in toronto seems pretty cheap. theres tons of 240s here and we even have a ontario club for it. soo parts isnt much of a problem.

[driftedsilvia]

if you want to just throw a new one on it go for it most than likely thats gonna be it..Just dont buy a used one. Its a very sensitive sensor some people damage it just by being to hard on the removal process. i know thats sounds stupid but it happens offten..le me know if you need the testing procedures. Im just asking first because thats a lot of typing to do but I got them...

[FUNGC]

just tested a new mafs today, and it was the same. this is really pissing me off. i need my car to work!

what other possibilities are there?

oyea and when my fuel tank is almost dry, the car run smooth like normal. i just cant gas it hard, or it will stall.
Modified by FUNGC at 4:34 PM 10/28/2006

[8-bit]

your engine is blown. how about that for an answer? its simple, its correct, answer complete.

[sean58888]

i dont think your engine is blown,if your car exhausting white smoke yes its going and soon be gone.anyway,i think you should do the following,replace a new fuel pump,clean the fuel pump filter bag,fill up the gas,take it out for a spin see what happend.canada is great,car get more power out of it there because the climate and weather.you should be leaner than super rich.....lol,let me know if my suggestions help!

[FUNGC]

your engine is blown. how about that for an answer? its simple, its correct, answer complete.

your answer is wrong and you are a stupid idiot.

[FUNGC]

i will try that out soon, first im going to change out the fpr, with an adjustable one and see what happens then. ill tell you how that will work

[tetsuo]

this will sound like a stupid suggestion but I recently had alot of shake to the engine to find out one of my ignition wires have come off. You should carefully try unplugging each one (and putting it back) to make sure disconnecting them (one at a time) should make it idle differently. Make sure they are in the right order too!

[nuts510]

the black smoke is its too rich, it's not very difficult to pull the codes out of the ECU I would try that first, the fact done plug and air flow meter helps it sounds to me like your air flow meter decided to die, also a shorted head Sender can rich in the mixture up a lot. But you're describing air flow meter death pretty much to a T. If you got a body they'll let you try his watch you try that you're also got I have to run the car for a minute or two to clean it back out. I hope this helps you out

[el_nacho17]

my 92 hatch is doing the exact same thing! i bought it cheap because it wasnt running good and i pretty much figured it was the mass air flow sensor. threw a new (used) one on and it is the exact same. im getting like 5 mpg so its really starting to piss me off. imma pry finnaly break down and take it over to my dad's mechanic for his car lot and see what he has to think about it. i dont have a cat so i know thats not plugged. id like to do a tune up to it butt i cant really because i'll just foul out the plugs again because of it running so damn rich.

[FUNGC]

the black smoke is its too rich, it's not very difficult to pull the codes out of the ECU I would try that first, the fact done plug and air flow meter helps it sounds to me like your air flow meter decided to die, also a shorted head Sender can rich in the mixture up a lot. But you're describing air flow meter death pretty much to a T. If you got a body they'll let you try his watch you try that you're also got I have to run the car for a minute or two to clean it back out. I hope this helps you out

hmmm... i dont quite understand what you are saying. and also what is a head sender?

anyways UPDATE! i tried another different mafs, and still the same thing. the tank has some 91 octane fuel in it now since it went empty. situation is still the same. but i havent seen as much black smoke anymore. still shakes alot.

this is stupiddd im getting pissed off at thiss

[wankelTII]

Well, cleaning an MAS with carb cleaner is the worst thing you can do, throw that MAS away. If you are going to clean it use electric connector cleaner, its the one at advance auto with the connector on the can, not the one with the alternator on the can, and not carb cleaner!

Read the code that your computer is throwing! Go back through and check all connections, you said your car ran fine before you took the engine out and unhooked everything, obviously you either damaged something or didnt hook something back up correctly. I am willing to bet its something simple, CHECK YOUR GROUNDS!!! If your block isnt grounded well enough none of your sensors will work the way they should. I have seen bad grounds cause all kinds of problems.

[FUNGC]

problem fixed. it was the ecu.

replaced it and i dont have any problems at all.

thnx for the help.

[Didderson]

I was going to say it's probably your MAFS ground. You can splice the black wire coming from the mafs if your ECU doesn't get a good chassis ground that'll solve lots of problems.<it did for me

[VanguishRacing]

they are mint. no cracks, and not even broken. the first engine i put in shooked alot. this one still shakes but it doesnt shake as much as the first engine. both are running very rich.

i also smelt the engine oil of the first engine and it smelt like gas...

im pretty sure the rings arent gone on my engines cause it would have caused alot of blowby, and it would have burnt oil, which if irc that blue smoke is burning oil, and black smoke is running rich.

if blue smoke coming is fuel and oil mix together...BADif black smoke coming out is...need oil change...when as the last time it change?if white smoke coming out is either your hg is crack or turbo is out.you are running to rich mean your injectors sending to much fuel to the motor and your spark plugs probably are fault out and is not given enough spark to burn fuel. So now at this point fuel and oil are mixed.

so now replace new spark plugsflushed oil, put new oil inif you are running with a sr and is tuned with safc or romtune...it need a good tuning again.

cause this happens to me because i'm running with a sr20 with a safc.

[sleepyS14]

if blue smoke coming is fuel and oil mix together...BAD

theres nothing wrong with blue smoke!! it's just different is all .. just different!!! DONT HATE BECAUSE WE'RE DIFFERENT!!

i hate blue smoke and it smells. i hate that smell. i hate my life.

but congrats on the problem solve-age!!