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VS Ecotec rough idle

EDGE3

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Yes the car will vibrate badly if the engine mounts are gone,but it wont idle roughly because of engine mounts,idling and vibrating are 2 different things altogether,it would have definately been contributed by the vacuum leak
 

gendi

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i could hear a vacuum leak everytime i applied the brake. had a mechanic look at it and thats what he said it was, so i replaced it and been fine since, grabbed a second hand one from the wreckers took about 10 minutes to install.

found this in a different thread: posted by Brett_jjj

first try disconnecting the brake booster vacuum line from the booster,then block it off with your thumb and run the engine,keep it blocked and see how it runs then,if it runs fine,the brake booster diaphram is probably faulty.
 

RX25SE

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@OP

Mine used to do this at around the 180k mark. It was almost stalling shifting from drive to reverse as the idle was so unstable.

Remove the DFI and clean/replace the zinc oxide grease underneath it.
Remove the DFI mounting bracket and clean the mounting surface for the module and the mounting points to the block.
Clean the block where the bracket bolts on.

The problem is the DFI develops an earth fault due to a small amount of corrosion between these points. Also the grease goes hard so it is less effective as a heatsink.

Once this is done, disconnect the battery for about 20mins to clear the memory.
 

primo

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Hi Guys.............another long one but pls bear with me :)

Just thought I'd give an update. The very rough idle is still bloody there. It does drive smooth as though.
Listed below what I have done thus far
and welcome any further suggestions. In a kind of weird way i enjoy the challenge of working out what the
problem is, even if it's driving me up the wall. I have bought the Gregorys manual.

Error Codes -

I received codes for the first time the other day, 22 & 23, relating to TPS and Air temp sensor. Cleared them and haven't received the errors since. I am replacing the ATS tonight.........the TPS is $170 from Holden!

Replaced so far with new genuine parts -

Fuel pump, fuel filter, CrankAS, CamAS, IAC, temp sensor and temp ECU sender, Fuel pressure regulator,
o2 sensors, new leads, checked plugs,injectors professionally cleaned,

Checked and or Cleaned -

removed manifold and plenum, cleaned inside out with new gaskets.
removed and cleaned Coil packs and checked resistance, engine mounts(mechanic told me they are ok but do I trust him?),
Harmonic balance feels and looks strong, ie, no play or wobble.
Chcked manifold purge hoses, swapped them around at the purge solenoid in case they need to be in some
order? One goes to the TB the other to the canister.
Removed and cleaned the starter motor and contacts, was black as but now starts beautifully!

Still to Check -

Cylinder Compression ?
Remove and clean the DFI (have removed and cleaned the coil packs and resistance ok) ?
ECU ?
May take the tank(ute) back out as one of the vapour hoses running from top of tank to the bottom near the return hose wasn't connected.......assuming this needs to connect to the canister vapour hose coming from the
canister in the engine bay?
anything else I am missing ?
 

nathanVY

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Wow did you really pay $170 for a TPS?

Engine mounts can be sagged/cracked but not snapped or broken. Try this, if your bad idle is only in drive and stationary;

Put car in drive and foot on brakes (don't crash into wall, mate, wife, etc, etc)
You should have your bad idle now.

Now just accel a bit and lift the revs up to say 1000rpm or just below and see if it isn't vibrating/idling bad.

If it's not then it could be the engine mounts, because if the passenger side mount is sagged then it will be sitting too low on one (or both) side(s).
When you torque it up the motor lifts.


Just a thought. I'm getting my engine and transmission mounts replaced this weekend so I'll let you know how it goes :D
 

primo

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Great thanks..........I'll test out mounts(should I get the mother in law to stand in front?). I didnt pay 170 for a new TPS! .............Repco sells aftermarket for 50 bucks if i choose to replace. Not sure though that a faulty TPS causes such a bad idle.


It's getting to the point where almost everything that may cause a rough idle has either been replaced or checked and cleaned.

Would worn rings cause rough idling?? As I get heaps of smoke when I open up the throttle 3/4 and up??
 

The1

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Dfi or dodgy coil pack most likely, how dirty was the Plenum? Could be gummed up pcv valve, if you search under my username you should find diagrams I posted a while ago of the purge lines, what colour is the smoke does it do it hot or cold?
 

primo

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Could be the DFI?..............checked the coil resistance individually and all registered ok. The plenum was dirty as expected, but cleaned all that and the manifold all up. Cleaned the PCV and at the valve was rattling
freely as described in the gregorys.

The smoke is noticeable when warmed up.............it looks whitish in colour when you fang it...........

BTW.......As I Have now replaced so much, I have spare original parts I'm willing to offload..... As the rough idle and bad fuel economy is still present, I am assuming there was nothing wrong with any of these in the first place. I have spare cam angle sensor, IAC, air temp sensor, fuel pressure regulator, coolant temp sender to ecu, leads.........all for say $60. Brand new all these from Holden are worth up to $300.
 

The1

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DFI pull it off and clean all the contacts, checking coil resistance doesn't really mean anything, when under load is a different ballgame, was the oil seperator under the pcv put back in correctly with the hole facing into the manifold? Smoke could be burning coolant from a leaky intake manifold gasket, very common on these engines.
 
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