VY S2 HBD LS1 AUTO BERLINA Serious idle issue and false MIL

[CommodoreHero]

Hay Guys

I own a vy S2 LS1 Auto Berlina and I'm having real bad idle issues.
When I start the car it's fine. Idles great.
Once it warms up you can hear a small miss.
But get in and drive it it goes away.
BUT
Stop at a set of lights or come to a complete stop then it will idle like a pig and feel like it's gunna stall and goes down to about 300 rpms then up to 7-750rpms.

Also if you sit it at idle either after accelerating or just at idle a MIL Check Engine light cones up on the dash BUT When I plug in my laptop it says MIL Check engine light status OFF When it is actually on.
There arvye
no stored codes.
No pending Codes
Nudda Zip ZILCH.

I have do e the following
Replaced Plugs
Leads
Tested plugs and leads
In order to test other sensors I need to know what sensor has what voltage or oh and so on but cannot find anything
Any help will be greatly appreciated.

Thanks.

 

[Towcar]

vaccum leak? Split in the PCV hose maybe.

 

[NU13]

Yes vaccum leak or perhaps idle air controller?

 

[CommodoreHero]

I want to test the IAC Valve but do not know what the resistance should be and what the Volts should be.
Also
1) What is the normal Vacuum pressure supposed to be.
2) How do I check the coils with a multimeter (What are the Volts supposed to be going from the wiring harness and out the connector plug. And what resistance should it read from the coil)
3) Is there any links anyone can share that can take me to any specs of these reading.

 

[CommodoreHero]

But do you guys have any idea why I get a Check engine light on my dash but when I plug in my laptop to the OBDll port it says that the check engine light is NOT illuminated.

It all started when I drove through some flood waters. It wasn't deep and slow moving. About a foot deep.

 

[st3r3otyp3]

But do you guys have any idea why I get a Check engine light on my dash but when I plug in my laptop to the OBDll port it says that the check engine light is NOT illuminated.

It all started when I drove through some flood waters. It wasn't deep and slow moving. About a foot deep.

With the ELM327 stuff I know what you talking about, read the post in the link and see if some answers lie within

https://forums.justcommodores.com.a...ow-about-obd2-elm327-diagnostic-cables.230186

EDIT...

"But as for available diagnostic software..theres alot of useless, rubbish software out there! Many of which cant read Holden faults codes! But there is a couple "good" software solutions"
-EasyOBD2 (free!) Developer prevents normal elm327 cable now. Cant read Holden specific info either.
-TouchScan (Paid.. but has free trial, give it a go!! Cant read Holden specific info either!)
-Software on ELM Street (SOE) (Can read Holden Specific faults codes and Holden specific engine data!)



The only thing that I think may have been disturbed driving through that water would be 02 sensors, vacume leak is what I would put on the top of the list though it would idle high on start up though, inspecting the PCV hose is hard as taking it off the engine may cause
cracks etc... to an otherwise fine hose.

 

[st3r3otyp3]

Oh also cleaning the throttle body should improve idle quality, take it off and clean it thoroughly with carby cleaner.

 

[CommodoreHero]

With the ELM327 stuff I know what you talking about, read the post in the link and see if some answers lie within

https://forums.justcommodores.com.a...ow-about-obd2-elm327-diagnostic-cables.230186

EDIT...

"But as for available diagnostic software..theres alot of useless, rubbish software out there! Many of which cant read Holden faults codes! But there is a couple "good" software solutions"
-EasyOBD2 (free!) Developer prevents normal elm327 cable now. Cant read Holden specific info either.
-TouchScan (Paid.. but has free trial, give it a go!! Cant read Holden specific info either!)
-Software on ELM Street (SOE) (Can read Holden Specific faults codes and Holden specific engine data!)



The only thing that I think may have been disturbed driving through that water would be 02 sensors, vacume leak is what I would put on the top of the list though it would idle high on start up though, inspecting the PCV hose is hard as taking it off the engine may cause
cracks etc... to an otherwise fine hose.

Hay mate.

Appreciate the info. I will suss it out.

I have been using EASYOBD2 For almost 3 year's now with great success.
I got the paid version. We used this to check fault codes and clear knock codes and MIL whilst turbo in my vz.

You need a decent ELM327 Cable as I had bought cheap shitters in the past and had that outcome. Wouldn't connect wouldn't read nothing but it would work fine in my wife's 2007 toyota.
But bought a good one and didn't look back.

I will now go to that link and see if it can help.

Thanks again mate.i really do appreciate your effort.

 

[CommodoreHero]

Oh and forgot to mention that I had already pulled to TB off and cleaned it all out.
Had a bit of **** in it but not to much.
The IAC Valve had a bit of **** on the pintle also so cleaned that to
The PCV hose is rock solid. As soon as it's touched it will go to ****.
I'm going to be plugging up the system and putting some low pressure in there and spray with soapy water to check for air leaks.
Also going to hook up my smoker to it and check that way to.

Will keep all you guys informed. Because there is nothing worse then finally finding a post that is EXACTLY the same issue you are having and then you get 10 pages in and find out that the last post says.
"PROBLEM Sorted. Thats to all for the advice and help. So glad that's done now. CHEERS"
AND THEY DONT POST UP THE SOLUTION OR THE REAL ISSUE OR THE END RESULT.
Sooooo hate That.

Well that's my wine done.

 

[franklinfrog]

When a car is warming up it runs in open loop mode, which means it doesn't use feedback from sensors but rather from predefined settings in the computer. Once it's warm it switches to closed loop where it uses sensor feedback to run smoothly. I'd suspect you have a sensor problem.

So maybe your temp sensor is stuffed and your car doesn't know what mode it's in. I'd be testing temp sensor and O2 sensors.

Have you ever successfully got codes from your VY using the gear you're using? There must be a code stored in there!!!