Spark plugs after break in (pics included)

Performance mods and Advanced Stroker discussion.
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98zjstroker
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Spark plugs after break in (pics included)

Post by 98zjstroker »

So finished breaking in the cam and doing minor driving around the neighborhood to see how she runs. Have a 98zj with the 258 crank 4.0 rods and Russ's awesome pistons. Upgraded cam and newer 99 intake manifold and new performance headers.

As of now still have stock ignition and throttle body that will be upgraded at some point. I reused the old plugs for break in only because they were fairly new and cleaned up well. Didn't want to buy new plugs to find out they were to hot and needed a cooler plug. I increased the gap to .45 on all of them for start up after doing some research.

So I can feel what I believe is a slight miss every now and then but my buddy says I'm being paranoid. Number 1 plug is at the top. 1-3 look good to me. Some of then have a silverish spots that wipe off. Not sure if that's from the antisieze grease or something else. Number 4 looks bad in the pic. But on the back side if it looks the same as 1-3. That silverish spot makes it look different in the pic. Now 5 and 6 are the ones that look "rich" or cold in my opinion.

Now when I rechecked the gaps 5 and 6 were gapped incorrect and more at .47-.48 I feel that is to much of a coincidence to be a fuel or cold issue. These are stock plugs. I feel the heat range is good and was going to just pick up a new set of stock plugs and be more careful with gapping to see if that in fact is the issue.

Anyone have any opinions or thoughts?
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98zjstroker
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Re: Spark plugs after break in (pics included)

Post by 98zjstroker »

Sorry bottonn pic is number from left to right with number 1 being on the far left. Top pick is part number. Second pic is number number 6 , 3rd is number 5, and 4th pic is cylinder 4 with the biggest grey silverish deposit
blay127
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Re: Spark plugs after break in (pics included)

Post by blay127 »

I'm having a similar issue with certain cylinders being richer/leaner than others. There were a few suggestions in a thread i posted

viewtopic.php?f=15&t=6275

Let us know if you find anything that helps or makes a difference.
Tolemar
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Re: Spark plugs after break in (pics included)

Post by Tolemar »

What injectors are you using? How does it run?
98zjstroker
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Re: Spark plugs after break in (pics included)

Post by 98zjstroker »

blay127 wrote: July 22nd, 2020, 10:06 am I'm having a similar issue with certain cylinders being richer/leaner than others. There were a few suggestions in a thread i posted

viewtopic.php?f=15&t=6275

Let us know if you find anything that helps or makes a difference.
I saw that same post. I ended up putting ngk plugs in that are one step colder. I am not convinced it's a lean/rich problem but that doesn't mean it couldn't be. It didn't help that the original plugs were not gapped the same. Not sure if this would cause issues since the gap was less then .5 off. But the two that were looked noticeably different then the rest.

I haven't had a chance to take it for a spin with the new plugs but will try today after work around the neighborhood. It does hesitate a lot more now when it is cold after the plug swap. Not sure if its because they are new or nor to cold of a plug. After I drive it around I will pull the plugs and inspect.
98zjstroker
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Re: Spark plugs after break in (pics included)

Post by 98zjstroker »

Tolemar wrote: July 24th, 2020, 10:06 am What injectors are you using? How does it run?
So I'm using the upgraded 4 port Bosch injectors from k Suspension. As for how it's running, it seemed to be good. A little hesitation on acceleration but that could be a trans/case issue. I did feel like there was a slight miss at times but my second o2 sensor was also bad and just recently replaced it. Idled good and started up quick without any issues. Just wanted to get some opinions as to how the plugs looked and if they were too hot or if I was running to lean.

I will check the colder plugs today and compare but I feel like the stock ones were better at least at idle
98zjstroker
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Re: Spark plugs after break in (pics included)

Post by 98zjstroker »

20200803_184554.jpg
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98zjstroker
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Re: Spark plugs after break in (pics included)

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20200803_184609.jpg
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98zjstroker
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Re: Spark plugs after break in (pics included)

Post by 98zjstroker »

so I threw in the ngk v power plugs that are one heat range cooler. They were gapped at .040. They were not ran for long, mostly at idle in the garage with just a little bit of time on the road in my neighborhood. Not really showing anything crazy different that would lead me to believe I am running rich or lean.

Still feel like there is a slight miss fire. Guessing its not the plugs or heat range that is the issue. Going to be hooking up a narrow band air/fuel gage that was donated to me from a friend. Mostly worried about running lean. Well paranoid since this is my first stroker build and don't want to blow it up.

Any thought or opinions would be great
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Re: Spark plugs after break in (pics included)

Post by KarmaKannon1 »

Might want to make sure all your grounds are in good working order also. Just a thought.

I did an aem wideband on my engine last weekend. It's nice being able to see that I'm not lean anywhere besides slightly while cruising which seems typical. They aren't cheap, but they do give you some piece of mind that otherwise wouldn't be there.
98zjstroker
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Re: Spark plugs after break in (pics included)

Post by 98zjstroker »

KarmaKannon1 wrote: August 4th, 2020, 9:57 am Might want to make sure all your grounds are in good working order also. Just a thought.

I did an aem wideband on my engine last weekend. It's nice being able to see that I'm not lean anywhere besides slightly while cruising which seems typical. They aren't cheap, but they do give you some piece of mind that otherwise wouldn't be there.


Will check the grounds next. As for the wide band, maybe in the near future, but this narrow band was free and will at least give me an idea of if something is majorly off about air/fuel mixture
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Re: Spark plugs after break in (pics included)

Post by Tolemar »

98zjstroker wrote: July 29th, 2020, 6:38 am
Tolemar wrote: July 24th, 2020, 10:06 am What injectors are you using? How does it run?
So I'm using the upgraded 4 port Bosch injectors from k Suspension. As for how it's running, it seemed to be good. A little hesitation on acceleration but that could be a trans/case issue. I did feel like there was a slight miss at times but my second o2 sensor was also bad and just recently replaced it. Idled good and started up quick without any issues. Just wanted to get some opinions as to how the plugs looked and if they were too hot or if I was running to lean.

I will check the colder plugs today and compare but I feel like the stock ones were better at least at idle
Second O2 sensor does nothing but tell the ecu the cat is doing it’s job. First one closest to engine is what matters. The second set of NGK plugs look good tan color. First set not so much.
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