VS commodore vibrates and idles low

[Z2TT]

Hi guys got the same problem, not very bad but i can feel vibrations through the steering wheel and a bit in the seat, other VS's i've been in didn't do this.
So I did engine mounts, new plugs, leads, cleaned the TB out and checked all hoses. Haven't checked my compression might be low but has lots of power and goes good.

When giving it a rev though in neutral, the whole car leans/jerks to one side - What could that be, could the ballancer cause that?

I'd give the ECU replacement a go too, sometimes capacitors go bad and cause problems. Maybe some sensors are getting old and causing bad running at idle?

 

[nathanVY]

FYI Mace Engineering sell powerbond balancers for ecotecs $123. Great company, i'll be getting one soon.

 

[The1]

pacemakers can throw the MAF readings out a little at idle making it not so smooth but shouldn't affect the idle speed, that would be IAC, it could need resetting

 

[astormsau]

I am wondering if taking it to holden to get the IAC correctly set might be worthwhile. I am wondering if by taking our IAC's out to clean them, and then putting them back in, if they are somehow getting a bit out of calibration causing this issue, apparently there is a correct procedure to set the IAC as it has 24 steps or something.

Drew

 

[The1]

i think it's ruffly 136 steps from memory, you can try resetting the ecu, pull the engine fuse under the bonnet for 20mins to reset, it will step the IAC then when you first start it up again.

Other than that a Scantool or Tech1 can restep and calibrate the IAC and also do step tests on the IAC with the engine running.

Im not sure if it's true but i have heard that they do reset at every start anyway.

 

[astormsau]

I have done all the ECU resets,etc... I think it might need calibration. with my motor I can actually see it kinda looks 'off balance' when its idling... if you look at the motor it shakes a bit as its idling although the actual idle is pretty consistent - it might vary by 50rpm but its just that there is this off balance vibration... it does it in neutral or drive but once you are in drive it feels worse... its intermittent as well, half the time its ok when you pull up to the lights and its as smooth as silk (you'd swear the car isn't running) and the other half of the time its vibrating through the wheel and seat... its also seems to be worse when cold and better when the car gets warmer and def better on a warmer day than a colder day....

Performance wise the car is great except that if you are just doing 80km an hour and its locked up the torque convertor and you only accelerate lightly then the car will vibrate a bit until you press accelerator hard enough to unlock the torque convertor... so dunno... trans and torque convertor are fine and car is running new leads and plugs and coils... so unless its the DFI board but ive heard they either work or they dont... got me stumped!

Drew

 

[nathanVY]

hmmm I have also taken my IAC to clean. Maybe this brings the issue as well. Can the ECU be "tuned" for pacemakers? Is that something the tuner should take care of. I havent had mine tuned yet, maybe that's what it needs.

 

[The1]

youve replaced your trans mount, how about your engine mounts?

an exhaust will flow more obviously so the stock VE and MAF tables will be off slightly about -4% - -10% Depending on setup and CAI, adjusting these can help, but usually BLMS will adjust most of it for you.

i usually tell people leave the IAC alone unless you have to, it can be painfull getting it to step correctly again.

 

[Brett_jjj]

Id try unplugging the fuel injector wiring connectors from each injector,one at a time, with the engine idling.This will show how well each cylinder is working.When you come across a cylinder that doesnt make much difference to the idle of the engine,then that cylinder needs further attention.It could be that the injector on that cylinder is blocked,a faulty spark plug or lead,or a leaking valve,or a ignition system problem.Hopefully all 6 cylinders will effect the idle speed about the same amount.Also its worth checking the contacts inside the DFI module wiring connector.These can get corroded and cause ignition problems.Make sure they are clean and shiny looking.Theres a small bolt that has to be undone to remove the DFI module wiring connector from the DFI module.

 

[The1]

Also if your ever getting a tune done make sure everythings in ship shape as if somethings not working it wont help the tuning!