Car shakes way too much

[druthafoo]

some basic info first:
1991 nissan 240sx
180xxx+ mi
ka24de

Just one day in the car my entire car is shaking at idle. My car doesnt idle at 700ish anymore but at about 1100ish. At this idle the entire car just shakes real bad. This has been happening for about two weeks, and I just dont have the time to look at it. Plus I drive my car about twice a week max.

From what I searched it could be a mount or a cylinder not firing.

What else could it be?

BTW I'm going to look at it(finally) just as soon as I finish up on some of this work. I'm going to try and test each cylinder by removing plug wires.

[SR20d2fourT]

Is it a steady idle or is it missing?


Mine shakes too....at 45mph + hehe

[druthafoo]

It idles around 1100 rpm pretty much a steady idle but the car itself is not steady.

[tougestyle]

look all your vaccum if no one are broken or have any crack.Look at your iacv remove it and go buy some carburator cleaner (make sure the spraycan have the protection for rubber and other things) shoot all your Carb cleaner in the iacv to be top clean and after try to adjust your iacv

p.s iacv=idle air control valve

[druthafoo]

lol at the iacv=idle air control valve

That'll be the last thing I do only because I don't have time to go out to the store right now.

[druthafoo]

So I figured it out, my third cylinder isnt firing.

Well I took off an one plug at a time when the car was running and each one would affect the idle except for the third one.

How can I fix this? (searching around atm)

[MadMaverick]

So I figured it out, my third cylinder isnt firing.

Well I took off an one plug at a time when the car was running and each one would affect the idle except for the third one.

How can I fix this? (searching around atm)

First you have to figure out where the spark is getting dropped or if the problem is somewhere else.

Shut the car off, plug the plug wire. Insert a screwdriver into the plug wire (where the plug would normally go) and lay it against a ground (the block, strut tower bolt, ect). Now start the car and see if there is a spark from the screwdriver to the ground. If there is spark, pull the spark plug and examine it for damage. You can use this chart:


http://www.aa1car.com/library/reading_spark_plugs.jpg
(http://www.aa1car.com/library/reading_spark_plugs.jpg)

Replacing the plug would be a good idea at this juncture.

If there is NO spark, you have to look upstream (plug wire, cap, rotor). Try swapping a known good plug wire (ie, swap cyl3 and cyl4 plug wires). If cyl3 gets spark, replace your wires. If this doesnt help, you have to take off the distributer cap and have a look. The contacts inside (little metal tabs) get corroded and worn. If they have white ashy stuff on them, its time to replace the cap and rotor. Likewise the rotor can get worn/corroded. However, if the rotor was bad, you would prolly get a misfire on multiple cylinders. If none of this stuff works, spark is not the problem.

[druthafoo]

First you have to figure out where the spark is getting dropped or if the problem is somewhere else.

Shut the car off, plug the plug wire. Insert a screwdriver into the plug wire (where the plug would normally go) and lay it against a ground (the block, strut tower bolt, ect). Now start the car and see if there is a spark from the screwdriver to the ground. If there is spark, pull the spark plug and examine it for damage. You can use this chart:


http://www.aa1car.com/library/reading_spark_plugs.jpg
(http://www.aa1car.com/library/reading_spark_plugs.jpg)

Replacing the plug would be a good idea at this juncture.

If there is NO spark, you have to look upstream (plug wire, cap, rotor). Try swapping a known good plug wire (ie, swap cyl3 and cyl4 plug wires). If cyl3 gets spark, replace your wires. If this doesnt help, you have to take off the distributer cap and have a look. The contacts inside (little metal tabs) get corroded and worn. If they have white ashy stuff on them, its time to replace the cap and rotor. Likewise the rotor can get worn/corroded. However, if the rotor was bad, you would prolly get a misfire on multiple cylinders. If none of this stuff works, spark is not the problem.
Ok I went ahead and followed your advice and every wire is sparking when contacted with the screw driver and ground.

I swapped the wires and plugs (only bc I had them already) but what can I do now?

[steve_o1989]

Now if you fixed that and you are getting spark, it is time to do a compression test on the 3rd cylinder...

I know I had low compression in one cylinder on my old sohc and it would shake like a bitch at idle. Maybe the reason it didn't make a difference when you pulled that wire, even if was sparking, is because somethings wrong with that cylinder.

[cotbu]

Did you check for fuel? See if that cylinder is getting fuel? You didn't mention smoke or gas smell! If, it is shooting fuel, change your oil after you get it started.

[racepar1]

So I figured it out, my third cylinder isnt firing.

Well I took off an one plug at a time when the car was running and each one would affect the idle except for the third one.

How can I fix this? (searching around atm)


Check the INJECTOR for the number 3 cylinder. Injectors are a VERY common failure on nissans, specifically 240's. The injector should have about 12 ohms of resistance, if it is out of spec then replace it. I have seen this A LOT! I have already had to replace 2 injectors on my KADE. Test your injector BEFORE you waste your time checking the compression.