Rough idle -Spark Plugs?

[Geoff6666]

Just done the same on my Redline, 112k kms. The original plugs looked almost perfect.

Same here. The plugs looked great at 100,000Km (on E85). I didn't notice any improvement with the new ones though.

 

[wetwork65]

I'll join in.
Just changed the sparkplugs on my SV6, 100k km.
The old plugs were only very slightly discoloured, much less than cars in the past e.g. the LS1s I have owned. Probably a good sign being so clean. Also noted zero oil anywhere around the coil packs.
Doing the L77 next week at 70k km, since they are almost 10 years old.

 

[wetwork65]

Just changed the spark plugs on my L77. I don't remember the job being so difficult on my LS1 engines. Or is it just me getting older? Pleased to find there was grease on the plugs, would be exfactory.
No difference before/afterthe plugs were change, but were getting very old.
Trying to get the plug back into Number 2 cylinder though was like the first time having s*x, finally finding the hole with my finger before I lost patience.

 

[dassaur]

Just changed the spark plugs on my L77. I don't remember the job being so difficult on my LS1 engines. Or is it just me getting older? Pleased to find there was grease on the plugs, would be exfactory.
No difference before/afterthe plugs were change, but were getting very old.
Trying to get the plug back into Number 2 cylinder though was like the first time having s*x, finally finding the hole with my finger before I lost patience.

Probably the easiest car I have ever changed spark plugs on haha!!

I don't think I've ever had a problem with any of them. What made 2 so hard? It's right at the front

 

[lmoengnr]

Probably the easiest car I have ever changed spark plugs on haha!!

I don't think I've ever had a problem with any of them. What made 2 so hard? It's right at the front

I thought #8 was the worst, kept slicing the back of my hand on the molded spigot on the side of the brake master cylinder reservoir.

 

[wetwork65]

Probably the easiest car I have ever changed spark plugs on haha!!

I don't think I've ever had a problem with any of them. What made 2 so hard? It's right at the front

I couldn't see the actual plug hole (what is the technical term?) in #2 due to the exhaust manifold position. I had to start the thread once I'd memorised where it was, by sticking my finger in the hole. The rest of them were easy as.
Many years ago, when I was a teenager, I cross threaded a spark plug in an alloy head by rushing the job. I've always been very mindful since.

edit: It was a 1974 Subaru. The alloy was probably not as durable as expected, I have just remembered that the engine had to get the cylinder liners replaced (or inserted) as a guarantee job when it was a few months old. I was far too young to understand what was going on and it was bought new by my disappointed parents.

 

[Sprog Dog]

That was likely from the ring catching on installation.

But the OPs issue is likely an injector from what I've seen on these engines.

Hi,

Yeah, could be. Having a 'discussion' with Holden about covering this under warranty when it's always been complained about since new. They say it can't be a manufacturing fault because the gouge is horizontal. It's 'fair wear and tear'. Seriously! Only done 97,000km

We had the injectors replaced but it made no difference......

 

[Anthony121]

I just realized the plugs for the V8 don't get changed until 150K kms. The VB6 is at 120k kms. I can feel the difference with new plugs in my car. It seems to be more responsive low down. I think now both cars feel the same as I always thought my Director had a little more kick.

 

[Skylarking]

Hi,

Yeah, could be. Having a 'discussion' with Holden about covering this under warranty when it's always been complained about since new. They say it can't be a manufacturing fault because the gouge is horizontal. It's 'fair wear and tear'. Seriously! Only done 97,000km

We had the injectors replaced but it made no difference......

The fact it has a vertical gouge within a bore (or bores) isn't material in concluding anything about how the gouge actually occurred. It could have been caused by a manufacturing issue during assembly. It could have been caused by some other failure that resulted in crud being sucked into combustion chamber via the intake or exhaust. Really it could have been any number of things that the dealer/manufacturer is liable.

To claim the cause is "wear and tear" after less than 100k kms simply brings into question the lack of durability for the engine and such can be seen as an acknowledgement that the engine just isn't durable in terms of what an average consumer would expect given the vehicles price. That's a failure of ACL acceptable quality standards defined under ACL.

What is probably more relevant for the moment is that you've complained about rough idle repeatedly while the car was under factory warranty. That should be the focus of the complaint, repeated complain of poor idle. So what the dealer/manufacturer should focus on is eliminating all likely causes, one by one during the diagnostic process. As Sherlock says "when you have eliminated the impossible, whatever remains, however improbable, must be the truth"... basically new engine time if they can't isolate the cause...

It's about time the dealer/manufacturer actually pulled their finger out and did some real fault analysis to get to the root cause. Then fix the issue you've been repeatedly complaining about (since presumably new car purchase time). Whether fixed under factory warranty or fixed under your consumer statutory rights is just a back office problem not directly relevant to you. But keep in mind that repeated minor faults will raise the issue to that of a major fault classification under ACL. Such will mean you'd be within your rights to choose the remedy and thus reject the vehicle and ask for a full purchase price refund (only if you bought the car from a dealer). Such gets them a little more motivated to solve the underlying problem for you (replace the engine?).

PS: injectors were a knwn defect and they should have been replaced under warranty (either factory or statutory) at no cost to you.

 

[Pollushon]

Plugs will usually break down under load before idle when they're cooked. Gouges in the bore are likely slap related, it's an LS thing. This was mine after 290k, that gouge probably appeared around 100k. Three cylinders in total. Didn't affect anything, I smashed 14 pounds through it for 60k, still going strong in another car at 350k