What are my spark plugs telling me?

zbc1969

Active Member
Joined
Jun 13, 2019
Messages
144
Reaction score
39
Points
28
Location
Utah
So I have a JB4 running map 1 and CAIs installed. Lately I've been getting an occasional misfire when I floor it and I'm in comfort mode. I figured a plug must be fouled so today I switched them out. Here's the coil packs and plugs from the passenger side of the motor. The other plugs and packs looked identical. upload_2019-12-1_17-40-12.webp
Does anything look wrong here? Am I running to rich? I need help figuring out if the Jb4 is causing issues and if I should get rid of it?
 
Can't see plug tips from your photos.
 
______________________________
When you have a misfire you will get a misfire fault stored. If you have a stutter that isn't triggering a code then it's not a misfire.

Let's see a log from when you feel the issue to see if anything stands out.

You could also have a failing coil that just isn't bad enough to trigger misfire codes yet.
 
Hmm no CELs were triggered. The only problem with logging it is that I can't replicate the problem. Is very intermittent. There is definitely a stutter though. Feels like a missed shift
 
From interior to exterior to high performance - everything you need for your Stinger awaits you...
Do the plugs look normal though? With all the dark spot around the electrode and the white chalk in the ignition coil?
 
upload_2019-12-1_19-16-3.webp
 

Attachments

  • upload_2019-12-1_19-15-50.webp
    upload_2019-12-1_19-15-50.webp
    97.7 KB · Views: 12
Those two look normal. Any cracked ceramic?
 
Could be knockoff plugs?
 
______________________________
From interior to exterior to high performance - everything you need for your Stinger awaits you...
No cracked ceramic, that's what I was looking for. Definitely not knockoffs either. Bought them from Rockauto
 
Assuming all your plugs look just like the ones you posted, then double check your coil packs. The tube can separate from the base, or the spring inside could be dislodged/out of place. It would be a good idea to double check the resistance of each coil pack as well - make sure they're all similar.

Now, if all that looks okay, then try new OEM NGK plugs. Seriously. Get a new set and gap them down to about 0.026" and see what happens. My bet is that you'll be running strong with no misfires afterwords.


Edit: BTW, your center electrodes look bent, or maybe they're just sitting at a funny angle. But if they really are as goofy as they look in your pictures, then you're not the first person to have that, and I doubt they'd be firing very effectively because of it. Just my $0.02.
 
Last edited:
Assuming all your plugs look just like the ones you posted, then double check your coil packs. The tube can separate from the base, or the spring inside could be dislodged/out of place. It would be a good idea to double check the resistance of each coil pack as well - make sure they're all similar.

Now, if all that looks okay, then try new OEM NGK plugs. Seriously. Get a new set and gap them down to about 0.026" and see what happens. My bet is that you'll be running strong with no misfires afterwords.


Edit: BTW, your center electrodes look bent, or maybe they're just sitting at a funny angle. But if they really are as goofy as they look in your pictures, then you're not the first person to have that, and I doubt they'd be firing very effectively because of it. Just my $0.02.

Ok how do I check the resistance of the coil packs?
 
Ok how do I check the resistance of the coil packs?

With a multimeter. You'll have to guess which is the positive terminal and which is the ground on the harness connector, unless someone here knows. I'm having trouble accessing my FSM at the moment, but even if I could it probably wouldn't be that helpful - I find it's usually lacking in detail. :/
 
(For a resistance measurement - it won't matter which one is the positive or negative terminal. Just measure across both.)

Check all of the coils - if one has a significant difference - that might be your bad coil ;)
 
From interior to exterior to high performance - everything you need for your Stinger awaits you...
Take this opportunity to put some dielectric grease on the boots. Also some anti-sieze on the threads.
 
______________________________
(For a resistance measurement - it won't matter which one is the positive or negative terminal. Just measure across both.)

Check all of the coils - if one has a significant difference - that might be your bad coil ;)


I only referenced the positive and negative pins because I can't remember if there are more than 2 pins on the coil pack harness connector.
 
Anyone know the pinout of the coil packs? Getting multiple misfires with Denso plugs so changed back to stock NGK but continue to experience misfires. There are four pins but I'm not sure which ones to test with my multimeter. Thank you!
 
Couple questions???

1. what brand are the plugs?(can't see in the picks but at least don't look like HKS - ask because I looked on RockAuto and didn't find right fit plugs for Stinger)
2. what is the current gap?
3. depending upon question #1, what is the heat range of said plugs(this can be confusing when trying to compare brands)?
4. what torque/tighten method are you using?

Random issue, confirm gap. issue happening regularly once engine is fully warmed up, see question #3. I am not second guessing any of the other responses but I inadvertently used an incorrect heat range on a different brand of plug and was seeing similar issues. HKS/Denso with 0.022 - 0.024 gap. way to go.....
 
I was getting some stuttering at higher throttle input and thought my plugs were fouled (had them almost 20,000 miles). I was using Denso 5346 IKH24 Iridium Power spark plugs which are 1 step colder than stock. I checked the gap and a few had widened to more than 0.024 (gapped to 0.022 initially). I swapped plugs back to the stock plugs and gapped them to around 0.023 and ran the car for a few hundred miles. That's when the check engine light would come on, multiple misfires. I re-gapped the Denso plugs and put those back in and removed my JB4 in case that was faulty. Tested again today and it ran great for 20 minutes and then boom, check engine -- multiple misfires on cyl 1,3,5. Not sure if it is a coil pack or something more serious. Any help would be much appreciated!
 

Attachments

  • Screenshot_20210615-095906_Torque_2.webp
    Screenshot_20210615-095906_Torque_2.webp
    105.5 KB · Views: 6
From interior to exterior to high performance - everything you need for your Stinger awaits you...
Back
Top