I know people hate long post, so in short

infiniti I30 with 120k miles.
The engine vibrates a lot when the car is moving very very slowly or stop. It does not vibrate when transmission is on N and P or the speed goes up. It's quite smooth on highway.
Spark plugs and pvc valve replaced. but vibration doesn't go away.

no engine light, no codes. idle rpm is 700.

what should I do to diagnose? Thank you!

 

Again, have you or have you not checked the coils?

 

sorry, forgot to mention that I didn't check the coil. I searched this forum and found one writeup about checking coil with multimeter. But I didn't understand one step in it. does anyone have a better reference?

so you think the misfiring caused the vibration? not a bad engine mount?

 

Well...WHICH step did you not understand? Saying there's one step you didn't understand then not telling us is pointless, you might as well not have mentioned it.

Also, how would we possibly know if we have a 'better' reference if you didn't tell us WHERE you read this writeup?

Asking us without giving us any information to answer with

The engine mounts won't make the engine misfire.

You need to clarify if it's just a little more movement than stock, or if it's actually missing.

If the engine's running smooth, it wouldn't vibrate excessively, torn engine mounts or not.

Did you try torque braking as per my recommendation in your other thread on this same exact issue (why did you even delete that)?

 

hello , guys

im having the same problem and i did change my coils but when i test #2 coil and swap #4 coil it just still messed up. so basic my engine is misfiring and i get the ecu code.. im running out of ideas of what to check please help!

 

Don't hijack other's threads, use the newbie thread. This is exactly what it's there for.

If we try to diagnose your issue in his thread, confusion will result for all parties involved.

The newbie thread. Use it. http://forums.maxima.org/4th-generat...sting-109.html

 

o and POMOR thanks for your effort into the community i really respect ya!

 

I read the post a couple weeks ago, can't remember exactly.(bad memory)
Just found the writeup by killcrap. I don't understand step 5 and I didn't see the 3 prongs. an illustration with picture would be very helpful.

Make sure the Car Is Cool for Safty Reasons.
for the right coils the one near the Radiator,
1) take off the 4 Allen Type Screws off With the right key.
2) Remove the Cover From The Engine The Thing That Says V6 3000 Nissan
3) Unplug the Harness and Unscrew the Two Bolts With the Right Sized Socket. Trust ME Its Easier to do it this way without a Phillips Head
4) Pull out the coil and use the multimeter and set it to the highest ohm setting too low could blow up ur Meter.
5) Take the coil and make the Long Part that was inside the Spark Plug and make it face it to the Right.

You Should See 3 Prongs Sticking Out

1 - 2 - 3

Use The Black Lead and Touch it to #3, and The Red Lead To Touch it To #2 If You Get An Ohm Reading other than Infinite or 1 You Need To Replace that Coil. and just Reverse the Leads Red Lead To #3 and Black Lead To #2 To Check For Continuity.

6) Now Just Do That To The Rest Of The Coils By The Radiator.

Coils by the Windsheild.
1) Unplug the Harness
2) Use An Extension to Reach The Bolt In The Back, And Front
3) Now Pull Out The Coil and Do the Same As You Did For the Right Coils. (Not Exactly Too Sure on which prongs to Test, (1 - 2 - 3) Just Guess and Check Blk 1, Red 2 or Blk 2, Red 1)
4) You'll Notice that the Right And Left Coils Are Different. ( So When You Order A New Coil They'll Ask You For Which Side)

Hope This Helps.







take a few minutes learning what is "torque brake", so what should I observe when I do torque brake?
I delete that one because it seems too long that people not patient to read it all.

thanks, pmohr

 

The three 'prongs' are the pins where the connector goes on the coil. What exactly is it you do not understand about step 5? Take the stalk that goes from the coilpack body to the spark plug, and face it to the right.

If you see the engine moving around quite a bit, then examine the mounts.

 

thanks for your explanation, I was just confused by positioning the coil.

Actually I searched the forum and found another guy saying: if engine moves a lot when you turn your ignition on, then the engine mount is bad. Do you think this is correct? The torque brake is kind of hard to do, because I need some brave person to watch the engine movement for me.

 

You'll always see some movement when starting (as I said in your other thread). Using the method above will exacerbate the issue, if your mounts are bad you'll know it.

You could just leave the hood up and watch it through the area between the hood and the windshield wiper cowl.

 

how much is the movement can we say the mount is bad ?

One short question about torque brake: when I release the brake, should I still give a deep press on gas? sounds a dangerous move. I should shout "fire in the hole" to scare away people to a safe place.

 

No, you'll want to let off the gas before you even think about taking your foot off of the brake pedal. You only need to do it for a second or so. If you see the engine rocking back and forth quite a bit, look into the mounts.

Should also fully engage the parking brake to at least mitigate any potential accident.

 

Thanks, I will do it tomorrow and report what I see.
Got to go to bed. too late here. good night!

 

possibly a bad vaccum leak?

 

I did the torque brake this evening. But the rpm was not high, only between 1000 and 2000(worrying of losing control). Before I released the gas and brake, I saw the engine was up a little bit(not shaking, like some force was pulling it up). After releasing both, I didn't see too much movement of the engine. Can I make a conclusion that the engine mount is good?

By the way, the engine sometimes make noise, sounds like a rapid "da da da da", and the engine's sound is very "cloudy", not clear. However, sometimes it goes away for a while, then it comes back for a while. was some part loose? or the gas quality has some effect on the engine. That's the weird thing.

 

can you please explain a little bit?

 

If it wasn't jumping around, the mounts are probably fine.

Without a sound clip of some sort, who knows. 'Cloudy' isn't usually a descriptive term used in reference to a sound.

So have you checked the coils yet?

 

I was trying to record one when it was on, but the recorder on my phone has very bad quality, can't hear anything.

I haven't checked the coils, I'm still recovering form 14miles run last Saturday. I don't have the strength to unplug the harness. are you sure it's coil?

 

I never said anything about the plugs, I'm talking about the coil.

No, I'm not sure. No one can be sure about anything unless you actually start testing stuff.

 

You replied very quickly, I was changing "spark plug" to "coil".

Let me find a time to test the coil first, I should eliminate possibilities one by one.

Thanks!

 

Hey Pmohr, in the coil testing instructions reposted by kisas, it does not state whether coils should be tested after car is warmed up. Would it make a difference whether engine has been warmed up prior to test or not?