My_Shaldan

i have a '90 240sx (auto). everytime i drive it and comes to a stop, it shakes. idling is on 750rpm not too high and not too low. i tried adjusting it but still, it shakes. i had the sparkplug and sparkplug wires replaced and check the timing, still shakes. im running out of ideas where to find the problem is. im pretty much sure that its not the motor mounts. i even went to a mechanic and he told me that my car is notorious for having that kind of problems.

any help would be very much appreciated.

drnovascotia

this is true, but doesn't mean it can't be fixed, my 240sx was like that when I first got it, now even with the AIV removed it's like a ROCK @ 650 rpms
Here's what I did
fuel Filter
Seafoam
Cleaned MAFS,
Cleaned throttle body - Helped a lot
plugs, wires
removed AIV
02 sensor

Dr.

My_Shaldan

i know this is a stupid question, but i have to ask....

whats aN MAFS? and where is its location?

same question for the AIV.

drnovascotia

AIV Is the tubing that goes all the way from the intake, through some tubes and such, all the way into the header. ********** has a walkthrough on how to remove it that I followed, it helped. If the air is going the wrong way in the AIV, your idle will be messed up, and losing performance.

MAFS = Mass Air Flow Sensor. In the intake, the thing that reads how much air is coming in, right before the filter.

Dr.

8240sx9

i also have the same problem w/ my 89 240sx hatch, when moving the thing is bad ***, but when waiting at a light it sounds like it wants to stall out. any ideas?

re037

same as what dr said. id clean out the injectors and check for any vacuum leaks. love these old threads

g3bio

so how would you suddgest cleaning them? stick something through the hose like a cloth and clean it or what? (noob here.)

Preston

Seafoam. Pour it in your fuel tank, pour it in your oil filler, pour it in the brake booster line. Cleans out everything and brings back the bang. Do it a few days before you change your oil, then drive with it a few days, then change the oil. Depending on how built up your crud is...it could be sludgy=bad for motor. 2 cans should do the entire car.

ReigH

yeah you need to clean your fuel injector... if that doesnt work then you need to replace it

re037

i wouldnt run it in the oil if you werent prepared to deal with any hidden leaks the sludge was blocking. but id definately run seafoam through the intake mani (via brake booster or throttle body) and gas tank.

Preston

I see that side of it...seafoam opened my leaks...but still...wouldn't you rather know there's a leak and fix it rather than let sludge build up and potentially cause a problem later?

Just for the argument's sake, I haven't fixed my leaks yet, I just keep checkin oil level and adding. Lol, I'll get around to it probably when I'm done removing my sound deadening.

re037

well it opened up my leaks too. thats im forewarning, cus i wasnt prepared either haha. rear oil seal is a *****. not enough time or money for an engine teardown. saving up to rebuild the spare block myself. fun times ahead.

Preston

Me also...not enough time for a teardown and rebuild...only problem...it needs it. Just started developing white smoke in the exhaust. Seems like I'll be needing piston rings in the near future. Damn racing on old engines lol...can you say boost prep time?

re037

no boosting for me. so cal: the car capital with the worst car laws EVER!

indyvang

my 89 240 with sohc motor shake and seem like its going to stall on me...when i first bought it, it wasn't like that...then after i change the alternator it started to happen...my clutch is runing low is slipping also...so it could be the clutch i don't no...especially when the motor is hot..id idle to 750 which it sopose to be when new but it shake like its going to stall on me..any suggesting