Car Is Shuddering / Vibrating For No Reason

[hotchoc]

Good Day all,

About 2-3 weeks ago my car starts to shake after i turn the ignition on. It will go away after a minute or so after i drive outside of the driveway. Occurs randomly. Thought it's something normal so i left it as it is.

Few days later when i start driving on the freeway the same thing will occur. The car will vibrate and shake for a few seconds. If it remains shaking / vibrating after a minute or so all i have to do is boost the car and the vibration will go away. This will occur when i'm driving about 70-80km/hr at the freeway. So what happens is i'll boost it to 100-120kph when the car vibrates at say 70kph and the vibration will just go away (not sure if this makes any sense)

So today arvo me and Brendan jack the car up to look for any exhaust leaks (checked out fine) and we also took apart the AFM and cleaned it with a electrical contact cleaner but it's still the same.

Also just drove to the city and along the freeway the vibration is getting worst. Was basically vibrating from my place all the way to the city. Tried boosting the car like i used to do but it seems to take longer to get rid of the vibration this time. Also noticed not gaining that much power when boosting the car as before and the exhaust is bloody loud now. Making a funny grumbling / misfiring sound.

Vehicle is basically stock. R34 GTT Series 2

Apexi pod filter.

Blitz Nur Spec Cat Back

Just changed my spark plugs last service from copper to NGK iridiums BKR6EIX gapped at 0.8mm

Any suggestions / help guys ?

[JLTS13]

it sounds like it may be your coils starting to go. you may need to look into that.

by vibrating is the car surging with a strange exhaust noise(ie popping/misfire)?

[br3ndan]

exhaust from what i heard is a very slight mis firing problem...

the coil packs is what we planning to look at next after eliminating exhaust leak, afm, sparks. Im assuming its only just starting to go a little bit hence the randomess of the problem occuring.

Best recommended way of testing coilpacks would be? Replacing all of them spitfires? or maybe using someones elses coilpacks to see if it fixes the problem.. and if it does then buy the coilpacks?

Or is there a way to test using a multi meter?

[hotchoc]

it sounds like it may be your coils starting to go. you may need to look into that.

by vibrating is the car surging with a strange exhaust noise(ie popping/misfire)?

yeah the car will surge with the strange exhaust noise

it's like a spluttering noise (i.e. putting an empty bottle and submerging it into a pail of water - those kind of sd if you get what i mean)

[B0oStEr]

It could be a vacuum / boost leak,

Check your intercooler and piping etc

[br3ndan]

It could be a vacuum / boost leak,

Check your intercooler and piping etc

if that was the case wouldnt the car have trouble holding boost?

His car holds the boost no problem...

Suppose it couldnt hurt to hunt around for the vaccum lines tho.

[hotchoc]

Well,

Guess we'll be doing something again next weekend Brendan? lolz

I'm just hoping my car can make it back home from the ct tmr

[JLTS13]

the coilpacks are a common problem, does it miss fire under load, say accelerating and does it start to do it around 5000rpm. if yes then l can safely say it is most likely coilpacks, if not try swaping in a known good set of coils and then try and if that fixs it buy some spitfires. Coils can be tested with a multimeter but it wont show up a intermitant fault like skyline coils have, because they have a problem with sealing and the spark jumps out the side of the coil in stead of tracking down the plug.

You can try taking the spark plug cover off then try driving the car at night and when it does it, look at your coils while the car is running and see if you can see any spark flashing around(sometimes you can see it in the dark). If yes get new coils.

hope that helps

[hotchoc]

Just took the car for a drive around for bout 15-20 mins.

No shuddering at all and it drives ok.

So..... wtf ???

[cosmic starz]

gee you sure got lots of guessswork replies - you need to start methodically - first you check for engine fault codes - takes about 1 minute and you only need some wire to do this - if you don't know how, search the site (its been covered maybe a million times)

and why would someone tell you to replace the coils or even check them unless you get a definitely got a Code 21 ?????????? bizarre!

see what fault Code you get if any- you may not get one come up at all, but even that points you closer to the real problem and figuring out what needs doing

if no code comes up it maybe something as simple as water in the fuel, blocked fuel line or filter, or dying fuel pump, among about 15-20 possibilities

[donutdavid]

gee you sure got lots of guessswork replies - you need to start methodically - first you check for engine fault codes - takes about 1 minute and you only need some wire to do this - if you don't know how, search the site (its been covered maybe a million times)

and why would someone tell you to replace the coils or even check them unless you get a definitely got a Code 21 ?????????? bizarre!

see what fault Code you get if any- you may not get one come up at all, but even that points you closer to the real problem and figuring out what needs doing

if no code comes up it maybe something as simple as water in the fuel, blocked fuel line or filter, or dying fuel pump, among about 15-20 possibilities

I agree with this reply 100% and just to add to those 20 or so possibilities you could have leaking intake manifold gasket as I do and sometimes misses on idle.

Good luck!

Dave

[hotchoc]

Tried opening my kick panel to check on the ecu but it seems to be stuck. NFI so i'm trying the pin method via the fuse box under the driver's dash

Tried the pin method and ............... 5 short blinks and 5 fast blinks which means code 55 - no malfunction

Ok now what guys ?

p.s. This test was done without driving the car for 10 minutes to warm up the car. Will this give out a false reading (55) ?

Edited February 9, 2009 by hotchoc

[Kujotk]

yeah do the test codes thing but if it sorta sounds like a wrx when it starts shuddering its most likely the coils, could be simple like the coils clip isnt connected properly, thats what my problem was, i just opend the plastic cover concealing the coil packs on the engine and clipped them all in properly.

also this may fit the reason why when you boost it goes away, you boost it, all the parts of the car that arnt fastend to the car in some way will move and this could mean that the connection is made again, its also better to check this now instead of later because ultimately this will damge the coil if it is a connection problem. then your up for $400 ish for a set of new decent coils.

this worked for me but it could be many other issues aswell, coils could just be on the way out, even a sark plug that is fouled or dying ect.... but it sounds like something to do around that area anyway...

[Kujotk]

also i really doubt its the exhaust at all, i ran my car for a bit of fun while chageing the front/dump pipe with no exhaust from the turbo back.... awesome sound, no shuddering, just sounded like a drag car...

[hotchoc]

will recheck the coilpacks to see if they are secure properly this weekend

i doubt it's the spark plugs as i've just changed em 3 mths ago from copper to iridiums

[hotchoc]

oh one more thing, if the coil packs are not secured properly will the fault codes show as 55 as technically speaking there's nothing faulty with the coils but just a loose connection right ?

[Howie]

As I was saying before on msn, give the coils a proper servicing before you go out and buy splitfires.

- remove the coils

- remove the boot, clean, and then hit it lightly with silicon spray

- using a metal brush, clean the tip of the coil pack

- reconnect it.

but if your coils are on the way out, no amount of servicing will bring it back to life.

ecu won't always give you a fault code if it's coil related.. it might if it was a power transponder though.

[Kujotk]

oh one more thing, if the coil packs are not secured properly will the fault codes show as 55 as technically speaking there's nothing faulty with the coils but just a loose connection right ?

I didnt get any fault code, and my coil plugs were loose because the mechanic doidnt clip them in, the car ran fine for 2 day than i went over a speed hump and the problem started....

[hotchoc]

just a small update ^

took the coil packs out and sprayed it with a contact cleaner and used a vacumn cleaner to suck out all the dirt and leaves (yes don't ask me how it got there) near the spark plugs

now the problem is gone - just hope it'll stay liek that for now

[Howie]

Good stuff