VF sv6 SII idle vibration/resonance

[diysv6]

I don't want to hijack this thread but do appreciate thoughts and discussion by members on the best way to look after our Alloytecs. After all, the engines do seem to be susceptible to poor maintenance practices, in some cases suffer design shortcomings, and this suggests that we should be prudent and address matters such as oil change interval v's workload, servicing intervals, engine malfunctions, dirty oil, gunk etc.

Since we are talking about a bad idle quality, not high RPM conditions, the "normal" condition at idle RPM, should be that there is maximum inlet manifold vacuum present. This vacuum should meet the engine designers' consideration of best/compromised scavenging of the crankcase through the crankcase ventilation metering hole in the engine cover.

If the IN and EX camshaft solenoids are faulty and/or camshaft timing gear drive devices are stuck in the high RPM function, then I guess the camshaft overlap/timing could reduce the inlet manifold vacuum. Looking around various sites, some sites have suggested that camshafts stuck in the high RPM mode can make for hard starting issues in some engines. Are the overlaps such that this could this happen in the Alloytec? No one reports a hard starting situation.

Are there so many crankcase contaminants, eg. oil vapour/solids/steam water vapour etc. at idle, that the idle quality causes what members are reporting? eg. Engine shaking at traffic lights etc. (Some engines have it, some have it but at a lower intensity, some people may not even notice it - eg. happy VE owners).

The metering hole as I understand it, is designed as a compromise between crankcase scavenging, idle speed, idle quality and inlet manifold vacuum. The vacuum being very handy for HVAC functions heating/cooling, power brake assistance etc.

An extreme case is the metering hole is totally blocked by gunk. If the piston rings are in poor condition and blow-by exists, then at engine idle, the clean air hose from the engine cover to the inlet tract reverses its inflow function and carries engine oil/vapours under crankcase pressure into the inlet track before the T/B. Hence an oil catch can be useful. This is demonstrated by an oily inlet tract and oil gunked throttle plate etc.

So, if the "metered" air/vapours from the engine's crankcase at idle are not a major contributor to idle quality, are we looking at ignition coils, spark plugs, fuel injectors, wiring/earthing faults, ECU design, timing air fuel mixture relationships etc.

A new can of worms for the VF?

 

[Davskii]

Holden gave the vehicle back on Monday and this week it feels worse than what it was when we took it in. Missus is getting really annoyed because they still can't pinpoint the problem. I'm starting to think that we're stuck with something that can't be fixed smh

 

[diysv6]

My VF SV6 also shakes/vibrates when I start it in the mornings. It started last August and also August this year. I've taken it back to the Holden dealership here in Cairns several times already (including yesterday, and they're keeping it overnight again). Apparently it's the coils playing up, so they keep telling me. It doesn't happen all the time but when it does happen it's like a mini earthquake in my car. Especially when I've stopped at the traffic lights. And also sometimes it loses power when I try and accelerate traveling between 30 and 50km/hr.

Given the range of idle problems experienced by VF owners, maybe the ignition coils are the next point of call.
Can a read of the spark plugs give an indication of missing or lean/rich mixture etc?

 

[pebbs]

To smashfist.

If the 3 different dealers I have used did their job correctly I wouldn't be "bagging" them as you call it.
Fist one. - Dropped my new Holden off for its first service just got home and the phone rang ." There is a problem with you car, our car carrier just back over it in our yard" was the call from the service department. When i asked what happens now the reply was "Its not our problem"

Second one - Another dealer - Dropped SS of for 20 000 klm service when I picked it up it had 93 kms extra on it and a quarter of a tank of petrol used. Tried to tell me it had to be "road tested" Crap' for 93 klms?

Third time - yet another dealer - Just had 15000 k service ( vehicle only traveled 8500k) Car wouldn't start next day - dead battery. Lifted bonnet positive terminal corroded under the cover so bad the terminal was broken off. Had to return vehicle 3 times to get the corrosion cleaned up properly.

While ever Holden continue to service and treat people badly I will continue to "bag" them as you put it regardless of what make or model I choose to drive.

 

[pebbs]

And if they don't exhibit the same "fault" then why cant the dealers mechanics fix it or are they not trained sufficiently to fix the problem, or is it just to costly for the dealer to please the customer?
When someone purchases a vehicle it is generally the second most expensive item they will ever purchase other than a home, and rightfully they expect the work carried out on the vehicle to be done in a professional manner by competent trades people, this is not clearly happening in some cases thus these type of particular forums surface.
Other makes are not exempt either, and with the technology of today's cars increasing so quickly I believe the technology is beyond some dealers mechanics.
The annoying part is from the dealer who gives a couldn't care less attitude to the customer and blatantly lie in order to justify their costs.

 

[AJAY79]

For those that are experiencing this issue, please try this simple experiment and report back -

Turn your AC off.

Yes, thats all - please give it a try..

 

[diysv6]

I'm curious,

Looking across the HVAC thread and the rough idle thread etc.
Is there any correlation between idle performance and the poor HVAC performance?


https://forums.justcommodores.com.au/threads/vf-hvac-design-fault-put-up-5.256391

 

[bigjim92]

I'm curious,

Looking across the HVAC thread and the rough idle thread etc.
Is there any correlation between idle performance and the poor HVAC performance?


https://forums.justcommodores.com.au/threads/vf-hvac-design-fault-put-up-5.256391

VF HVAC is ****, doesn't matter if it's a V6, V8 or LSA. Issues won't be related.
However having the AC on naturally means the compressor is putting more load on the motor, potentially adding to the V6 vibration at idle.

 

[AJAY79]

Interested in some feedback from those that have done the air-con off experiment.

How big of a difference did it make?

When i described the issue to my dad ( over 20 years with Holden in product development / product training / diagnostics ), he immediately suggested the air-con.

I reckon he is right..

 

[treesnake]

the resonance im experiencing is something out of balance, most likely the torque converter because it is happening at just above idle.

when the aircon is on, the bumps up the rpm into that resonance zone, and yes it the car does shutter then.