92 KA24DE weird shaking...

[SilGuy]

'92 KA24DE w/ 160k has this weird vibration at exactly around 3k rpm. Recently, I've had a fuel injector problem that caused misfiring in #1 cylinder so i changed it w/ a used DE injector(blue dotted). Could this be the culprit? I've noticed some DEs came w/ blue dotted injectors in cylinders #1 and #3 but others didn't. Mine didn't, but i changed my screwed up one to a blue dotted one. I've changed the MAF and o2 sensor so far and i've checked my distributor and its components r all workin properly. Could it be my TPS?? I know for sure it's the engine because the vibration is there while i'm not moving and I jus raise the rpm to around 3k. The vibration starts at around 2700 and go away after around 3200rpm. The vibration can definitely be felt and its louder than normal. Just feels like the engine isn't running smooth... Any opinions? Thanx in advance..

[574-240sx]

Is it a rattleing in the engine or is physically shaking. Also to check the plugs to see if one is lean and not getting fuel. You also might have a clogged injector too. I have a complete set injectors out of a 93', they all work great for sure. I took them out to run bigger injectors for the turbo.

Nick

[SilGuy]

its not really shaking that bad. It jus has this weird unstable vibration right around that rpm. My idling is fine. Just around those rpm that vibration occurs. I've checked my plugs when i had that bad injector and they are fine. thanx..

[SilGuy]

Update and Bump.. I noticed this vibration is very minimal if it even exists at start up or when engine is cold, but is very apparent when the engine is warmed up. thanx

[s13sr20chris]

is the vibration a rough running condition from the engine? or is it drivetrain type stuff.

[SilGuy]

the vibration is a rough running condition from the engine..cuz i can just sit there and not move and rev up to around 3k and it will vibrate like it does when driving...thanx

[s13sr20chris]

you, my friend may have run into a weird transient missfire due to incorrect a/f ratio or timing. that is dificult to track down. you have to monitor a everything possible and decide if its far enough out to cause your issue. that or it could be motor mounts or and accessory drive problem.

[SilGuy]

thanx for the reply. I will check timing, which I haven't done yet. Am i supposed to re-time it after changing injectors? Can timing just be out of wack? Cuz, the car was running perfectly fine before all this. I know it isn't drivetrain issue cuz I can sit there and not move and rev it to around 3k and it will vibrate weird.

[s13sr20chris]

timing should not have gone out of whack but an injector should not cause rpm specific vibrations either.

[SilGuy]

k. Well, i checked timing and it wuz off. I set it to stock timing and problem seems to be less, but is still apparent.

[s13sr20chris]

hmmm, the only thing i can think of that happens around 3k is o2 sensor stops being watched by ecm. its at like 3600 rpm or something though. maybe try taking your dist cap and rotor off. then take off the little plate under the rotor untill you can see the "rotor plate". it has 360 little holes in it. clean it with brake parts cleaner(from parts store in aerosol can) and let air dry. put back together and check. i have seen that cause those type of probs before.

[SilGuy]

thanx for the reply. I jus changed the o2 sensor when the injectors went bad. I will check wut u suggested. I had another suggestion that it could be the motor mounts. A friend said it did exactly wut its doing on mine on his friend's civic....