I just want a COLDER spark plug, that's all.

[Motivated]

Is it so hard to ask? This used to be simple. NGK was a higher number, Autolite was a lower number, etc. Now I can't find one hotter or colder for most of these new vehicles.

For some background info I have been having some SERIOUS issues with detonation in my car that I have been logging via HPT. EVEN ON A 100% STOCK FLASH, before I even attempted to tune the car I was seeing knock all over the place and some times it wasn't even at load, just cruising. We have ruled out any loose parts, the ground on the cylinder head (as advised by a TSB), and the fuel I'm using.

Common sense tells me next that my spark plugs are just too hot as the car has now started misfiring both at WOT (bad enough to flash the CEL) and at idle that I can physically feel. It's mainly showing in cylinder 1, but the other day I got a misfire code for cylinder 4. The dealer is pretty much saying to bring it in and look at it, but they have no fix for it. So there is nothing they can do and I'm not wasting a 150 mile trip to the dealer for nothing. Even called Saturn and the moron on the phone was like "Err...Ummmm....take it to a dealer? Then call us maybe...ummm....I don't know." This is getting really frustrating because the car is running MAYBE 3 degrees advanced at WOT on a good day, if I'm lucky. Sometimes it's even running negative.

The guys on the HPT forum have been helpful thus far, but there is no solid answer yet and I think a bunch of us are just scratching our heads. I can deal with one or two counts on occasion, but were are talking about 5 counts every time I even move the gas pedal pretty much.

I am getting knock in all 4 cylinders as per the readings from both knock sensors. I am also misfiring in all 4 cylinders as per the stumbles and readings in the HPT scanner. I am 90% sure a colder spark plug is going to fix it BUT I CAN NOT FIND ONE FOR THE LIFE OF ME. Anybody have any from the 07 cars before they did the TSB to change them all? Thank you very much.

[cerberus]

If your wiring checks out, sounds more like a bad sensor. If ya do want the old plugs, believe the old AC Delco 41-102 plugs were replaced by TSB to the hotter 41-108 plugs.

[Motivated]

Problem is, no one has the 41-102 plugs.

[cerberus]

Originally Posted by Motivated

Problem is, no one has the 41-102 plugs.

Ah. To your original question, folks who had their dealer do the TSB plug swap wouldn't have had the opportunity to keep their originals. 'Course maybe someone changed their own, so can't hurt to ask. Keep us posted on what you find.

[RedHeaded RedLine]

Originally Posted by Motivated

Is it so hard to ask? This used to be simple. NGK was a higher number, Autolite was a lower number, etc. Now I can't find one hotter or colder for most of these new vehicles.
...I am getting knock in all 4 cylinders as per the readings from both knock sensors. I am also misfiring in all 4 cylinders as per the stumbles ...

Not a solution but you could put a wrap of teflon tape around the knock sensors threads, to desensatize it. -J

[Motivated]

No, I prefer not to half ass this resolution. There's a reason the cars run two sensitive knock sensors and it's because it runs at like 13.0 AFR under boost. I'd rather fix the problem than cover it up.

[RedSkyMan]

This reminds me of a long time ago when I had a 57 Chevy with a 62 Vette short block with 56 heads. It had a compression ratio around 13 to 1 and the only way I could keep it from knocking or for that matter shut off, was to run It on Sunoco 260 (which is hard to get anymore), use Champion J8 plugs (the coldest I could find) and retard the spark about 8 degrees. We didn't have sensors and computers running everything back then.

[GM Roadster Club]

Originally Posted by Motivated

No, I prefer not to half ass this resolution. There's a reason the cars run two sensitive knock sensors and it's because it runs at like 13.0 AFR under boost. I'd rather fix the problem than cover it up.

It's actually a 14.0 AFR under WOT.

You should be running ~10* of advance under WOT as I am sure you can see in the tables. We have seen a lot of these motors suffering from misfires while stock. From our experience a revised cam phasing table is required to adjust the overlap of the cams during those "eventful" times.

And also, going to a HOTTER plug on the '07s was part of the fix, and is the current plug in the 2008. You should check to make sure that you have the recommended 2008 plugs.

Steve - GMRoadster Tuner

[kennysabarese]

Originally Posted by cerberus

If your wiring checks out, sounds more like a bad sensor. If ya do want the old plugs, believe the old AC Delco 41-102 plugs were replaced by TSB to the hotter 41-108 plugs.

TSB for plugs? would that apply to an 07 Redline?

[GM Roadster Club]

Originally Posted by kennysabarese

TSB for plugs? would that apply to an 07 Redline?

In most cases the 07 Skys are in the clear since they were produced a little later than the Solstice GXP. But it may still be worth checking out.

[cerberus]

The VIN breakpoint for the plugs TSB is 7Y139741. The TSB was posted here: Spark Plug Upgrade VIN Number Break Point

[SaturnSkyDude]

Let me know what you find out. I called a few auto parts stores and surfed the net and came up with nothing cooler than what I have. My Saturn dealer did the TSB since I have a 07 Redline and told me the cooler plugs I had are no longer available.

[Motivated]

Well I have bit the bullet and decided to drop it off at the dealership and let them run through it (or perhaps run over it) for a few days. Hope all goes well. Wish her luck!