Strange idle problem with GTM SC Stage 1

Alchemy

Agreed, Im contimplating a GTM stage 1 supercharger kit.

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Ryan
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toner123

I may be wrong in this case of info but from the research I did when i was going to buy these plugs, the stock plugs in our car use the same ones as a GTR which are already heat range 8. Both part numbers are the same for the plugs if you were to order them from nissan. This i did call a dealership also and confirm, so it is safe to say I do not think the heat range of your plugs are the problem.

Kirkster

Mine will also stumble at idle from time to time and only when hot. I have never worried about it much.

Running the factory plugs as my plugs got to the house after I had already gotten the intake back together. Was more of a pain than I wanted to endure to take things off to get at the plugs in the middle of the SC install.

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VQStryker

true statement about the stock plugs they are teh coldest we can use at the moment on these cars and are made by bosch. No reason to really change them out for I high price brand such as HKS.

EDIT: I found out a couple months ago when I was looking for a colder plug and contacted summit racing

weiboy718

part # from GTM
50003-M40HL HKS Sparkplug8HR

you should def ask a expert before taking the plunge though.

Jordo!

I doubt it's the plugs. Only if you had misfire codes coming up.

It's probably either reading a poorly tuned load cell at idle, an intermittent vac leak that causes a sudden misread, or something screwy where the belt is slipping and the idle revs up to catch the stumble. I guess it could also be something wonky with the MAF temp sensor readings too.

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Nixlimited

Can you data log when this happens?

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theDreamer

Mine will do this when it is hot/warmed up.

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wind.zero

Now I am wondering if it is normal because a few other people have the idle drop when the car is at operating temperature.

After going back to the stock cats (over 2k miles) I am throwing no codes and the stock plugs are in the right heat range. This makes me reconsider changing plugs.

I forgot my laptop today, but I will try and data log it tomorrow.

Thanks for the help.

wind.zero

Just a short update

Sam gave me a shout on the phone and I do not think this is a big deal. I am going to check some things and will update here.

Three things to check for this minor issue.

Spark Plugs
I cannot remember 100% what the shop said about my plugs during the install. I know they pulled them to verify the heat range and I used the original plugs. After talking with Sam, I doubt they changed the gap, but I am going to pull them to make sure. I may also go one step colder with new plugs.

ECU Correction
The ECU maybe be overreaching. I am going to get some readings and data logs and see the correction factor during various driving conditions.

Idle Learning
This is the 3rd step after checking the 2 above.

For those of you on the fence about the GTM kit, I suggest you take the plunge. I have been more than happy with the results. It is hard to wipe that S_ _T eating grin off my face lately. I was more or less curious why the car idled funny and this is not a serious problem. It is my DD and I notice things.

theDreamer

That is when I noticed it, daily driving my car is the only time it occurs.
If I drive it on a Saturday, no traffic around town it is fine, but sitting in traffic or hot days is when mine will drop then bounce up.

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wind.zero

This exactly.

Just got off the phone with my tuner, and he assured me my spark plugs were just pulled as a verification process. There was no adjustment to the gap.

I am going to do what Sam suggested with checking the ECU correction, but I bet the idle needs to be relearned. Mike @ Bullitt@UAMotorsports suggested this earlier in the thread. The board is a great source of information.

toner123

I dont think your understanding what I said earlier. Not trying to be a *** when I said that, just want you to have all the knowledge so please understand that. There is no one step colder plugs for our car. The stock plugs in your car are the same ones the GTR use. The heat range on the stock plugs is heat range 8. There is no colder plug then that on the market currently. Just don't want you to go buy heat range 8 plugs thinking your getting colder ones when in fact your putting the same ones in your car that you have currently and end up wasting money. Like I said earlier your spark plugs are not the problem. Like Jordo said you would have a CEL if it was.

wind.zero

No worries and thanks for the information. Going one step colder was something Sam suggested on the phone today.

I am actually not doing anything with my plugs. After having a chat with Kenny (my tuner) nothing was done with my stock plugs. The installer pulled them to check that they were the correct plugs, no harm in that. It was just a verification process which is a good practice. I thought I recalled something about the gap being changed, but I was wrong. That was my ignorance.

I appreciate the information and understand where you are coming from.

weiboy718

Maybe it was my fault for being it up haha.