Problem with my 240SX.....I will appreciate your help

[kokos]

Hey guys, hope everybody is doing well.

Today I changed the spark plugs, air filter, and fuel filter in my 240SX.

Since then, something weird is happening. The car is "choking", the engine is shaking, the RPG do not go over 500 (instead of close to 1000 when the car is idle). When I insert D (its automatic)
it is choking and dies on me.
At every stage, the engine is shaking a lot if I insert R or D the RPM go down and it dies on me.

Does any of you know what could be wrong?

I own a 1990 Nissan 240SX, 4 cylinder 12 Valve.

I am frustrated , because I trying to figure this thing out.

I will really appreciate any input from anybody.

Best Regards,

George Stratis:confused:

[ALTRNTV]

try wiggling around yer MAF (mass air flow sensor) and see if it still "chokes"

[Punisher]

hey, i know what u are talking about cuz i have the exact same problem and i also have a 90' 240sx but 5 spd, and i also changed the sparks and wires, the cap and rotor, the air filter, fuel filter which is off a 300zx (would that change anything???). it is also frustrating me cuz when my car is idling and u press on the throttle lightly it boggs and alot of the times it stalls.
I have posted a thread just a few posts down and i dont know what that piece is that i have in the pics but i think its the idle control unit, and when i took it off the hose under it was melted off and the unit was clogged, i cleaned it out and put a new hose on but it didnt change anything......so i am still stuck and my car is at my buddies house cuz it wont start and when it will, it dosent stay on for long.....so i left it there.

[fastpace]

i had something similiar happen to me. try getting some carb cleaner and clean the throttle body. open up the inside by turning the nob. it is best to use an old tooth brush.

[kalieaire]

are you running rich? try replacing the seals on your injectors, or just replacing your injectors altogether.

here's to test to see if its the injectors that's causing you problems.


start your car.

pop the hood up

pull out the spark plug wire for cylinder 1 (don't worry, it's insulated very well, it's practically impossible to get shocked)

if your engine has even more difficulty idling, put the wire back, and proceed to the next cylinder.

if your engine has no more difficulty than it currently has idling, you've found one or more cylinders that are causing your engine problems.

most likely here you'll have a problem with; 1)ignition, 2)fuel delivery in too much or too little.

this test is called a "power balance" test. go try it and tell us if you're successful in finding out what's wrong!

don't come back until you've tried it because this test only takes 2 minutes!

[mrmephistopheles]

out of curiosity, did you ensure your plug wires are going to the right places on the distributor cap?

[kalieaire]

well, now that you've found out that you have two cylinders that are causing you problems, don't think that you're done with diagnostics just yet. =D

as I said previously, it's one of two problems, either ignition or fuel.

to test if you're getting spark, take out the spark plugs and plug them into the boots, put the base/threads of the spark plug onto the some part of the car that's grounded.

now have someone help you crank the engine. if you see sparks coming from all four spark plugs, then that's good and you can discount that problem.

if they're not sparking, then you've got a problem.

there are only a few reasons that can prevent your plugs from sparking. wires, cap, rotor, and ignition coil. but I think we can rule out your coil since your car run, albeit be like crap.

------Next, diagnosing the fuel system.

As you said in your email, you seem to have two cylinders that are bad, meaning the other two are a-ok.

I tell you now that the 1990 and 1989 SOHC engine had a notorious problem with leaking injectors and o-rings being eaten up by the gas.

So you probably have leaking injectors, there's a rarer case in which your injector harness could be grounded prematurely causing your injectors to be held wide open. that's no good, but like i said, that's rare.

To rememdy the fuel injector problem, you need to do one of two things because two things may be causing it to leak.

1) the o-rings surrounding the injector and hold it in and keep it from leaking fuel are broken, you can replace these with a few replacement injector o-rings sold at your nearest autoparts supply store (remember get the ones for the 1989-90 240sx). take out your injectors, put on new o-rings, make sure they're dust free, put on some white lithium grease on them and plug'em back in. the o-rings should be WAYYYY under 10 dollars. like at my local kragen they're 1.79 a pack.

2) the injectors are the direct cause of the problem. best thing you can do is to replace them.

you might want to put a WTB in the classifieds saying you want 240sx ka24e 1989-90 injectors. a lot of the time you can get all four for about 50 bux. It sure beats paying ~ 100 a piece at an autoparts store.

---good luck.