Misfire with Procharger Recommended Plugs

cjperformance · 07-17-2021, 03:50 PM

Had my procharger p1x working fine for a couple of months here with stock plugs. Finally got around to replacing the stock plugs with the recommended NGK 6510 with .035" gap hoping for even better results.

Getting bad misfire under WOT, but running perfectly fine at less than maybe 75% throttle.

0x7E8: P0300 - Random Misfire Detected (Pending)
0x7E8: P0303 - Cylinder 3 Misfire Detected (Pending)

Obviously I'll check cyl 3 first. I reseated the plug wire on that cyl. But the random misfire kinda makes me think the overall config is just wrong.

Since it runs find at less than WOT, makes me think it's not a completely bad wire or plug. Its still firing, just not under full load.

Changing those plugs is a pain, so thought I'd get some input here on what I might try next.

Was going to open up the NGK plugs to .040" first, if that doesn't work, I'll put the original plugs back in.

Wondering if anyone else has experienced anything similar.

UPDATE/EDIT: The TLDR... the recommended plugs and gap work MUCH better than the OEM plugs. It was a damaged plug wire or two that was the issue.

Joshinator99 · 07-17-2021, 05:11 PM

Are you running headers? The stock plug wires, in my case, got brittle very quickly and weren’t happy coming off...easy to develop a crack IMO. I know some have had success, but not me. Lol

Plug could have gotten cracked during install. Did you buy a spare plug you can put in that cylinder?

LiqTenExp · 07-17-2021, 06:58 PM

Quote:

Originally Posted by cjperformance

Had my procharger p1x working fine for a couple of months here with stock plugs. Finally got around to replacing the stock plugs with the recommended NGK 6510 with .035" gap hoping for even better results.

Getting bad misfire under WOT, but running perfectly fine at less than maybe 75% throttle.

0x7E8: P0300 - Random Misfire Detected (Pending)
0x7E8: P0303 - Cylinder 3 Misfire Detected (Pending)

Obviously I'll check cyl 3 first. I reseated the plug wire on that cyl. But the random misfire kinda makes me think the overall config is just wrong.

Since it runs find at less than WOT, makes me think it's not a completely bad wire or plug. Its still firing, just not under full load.

Changing those plugs is a pain, so thought I'd get some input here on what I might try next.

Was going to open up the NGK plugs to .040" first, if that doesn't work, I'll put the original plugs back in.

Wondering if anyone else has experienced anything similar.

LT4 are 0.030" stock, you may want to try in that range to start?

I've had my fair share of misfires lately and I'd try the following:

Gap to 0.030"
Swap plug wire with another cylinder
Inspect coil harness and make sure contact locks are not broken
Swap coil pack with another cylinder

cjperformance · 07-17-2021, 08:12 PM

Thanks for the input. Good points, all. I'll start with new plug wires. Sounds like the plug gap isn't likely to be the problem based on some of the above, and I could definitely see how the wires could be brittle and damaged.

Chevy1American · 07-18-2021, 04:54 PM

Gap the plugs to .042

thats what i run on my D1X set up

Joshinator99 · 07-18-2021, 05:17 PM

Quote:

Originally Posted by Chevy1American

Gap the plugs to .042

thats what i run on my D1X set up

Too wide, in my humble opinion.

SSUNDVL · 07-18-2021, 05:20 PM

Was the car running fine when you swapped the plugs?

cjperformance · 07-19-2021, 09:05 AM

Ordered some new Granatelli plug wires. Easiest thing to try first. Will update in a week or so once I install them.

Chevy1American · 07-19-2021, 03:17 PM

Quote:

Originally Posted by Joshinator99

Too wide, in my humble opinion.

I just followed exactly what my tuner Ted Jannetty told me to do and the car has been faultless since he tuned it remotely 2 years ago

SSUNDVL · 07-20-2021, 07:48 PM

Quote:

Originally Posted by cjperformance

Ordered some new Granatelli plug wires. Easiest thing to try first. Will update in a week or so once I install them.

If the car was running fine before you switched the plugs why would you change the wires? I would double check the plugs to make sure you gapped properly and no porcelain is cracked.

Joshinator99 · 07-20-2021, 08:11 PM

Quote:

Originally Posted by SSUNDVL

If the car was running fine before you switched the plugs why would you change the wires? I would double check the plugs to make sure you gapped properly and no porcelain is cracked.

Because every time you yank off the original wires you’ve upped the chance of damaging them, especially if they’re a few years old or have some mileage on them. They get brittle over time. If the car has headers, even ceramic coated, they will never live as long as heavy duty wires like Granatelli. I know others have lucked out, but no one I know personally has. The difference in quality of the Granatellis over OEM is substantial.

I agree with your point about the plugs, definitely worth checking the gap and inspecting for cracks. Frankly, I always buy an extra plug or two every time I buy plugs. If you drop one or ding it during install you’re better off not using it IMO.

cjperformance · 07-21-2021, 11:57 AM

Quote:

Originally Posted by SSUNDVL

If the car was running fine before you switched the plugs why would you change the wires? I would double check the plugs to make sure you gapped properly and no porcelain is cracked.

Troubleshooting 101 - Examine the possibilities, make an assumption, test your assumption

Its entirely possible a plug or two was damaged, but I dont think so. Changing the plugs was very unfun... so since I want to upgrade the wires anyway, makes sense to try that first before I pull out the plugs again.

However, if the wires dont fix it, then its almost guaranteed to be a bad plug or just bad config in general.

Wire should arrive today sometime, but wont have a chance to install until the weekend.

SSUNDVL · 07-21-2021, 12:41 PM

Quote:

Originally Posted by cjperformance

Troubleshooting 101 - Examine the possibilities, make an assumption, test your assumption

Its entirely possible a plug or two was damaged, but I dont think so. Changing the plugs was very unfun... so since I want to upgrade the wires anyway, makes sense to try that first before I pull out the plugs again.

However, if the wires dont fix it, then its almost guaranteed to be a bad plug or just bad config in general.

Wire should arrive today sometime, but wont have a chance to install until the weekend.

this is one of the easiest cars to pull plugs on lol

Puddin · 07-21-2021, 02:21 PM

Quote:

Originally Posted by SSUNDVL

this is one of the easiest cars to pull plugs on lol

I have to disagree. It's a pain in the ass especially with 2in headers.

07-17-2021, 03:50 PM	#1
cjperformance Drives: 2017 Camaro SS 50th Anniversary Join Date: Apr 2021 Location: Missouri Posts: 929	Misfire with Procharger Recommended Plugs Had my procharger p1x working fine for a couple of months here with stock plugs. Finally got around to replacing the stock plugs with the recommended NGK 6510 with .035" gap hoping for even better results. Getting bad misfire under WOT, but running perfectly fine at less than maybe 75% throttle. 0x7E8: P0300 - Random Misfire Detected (Pending) 0x7E8: P0303 - Cylinder 3 Misfire Detected (Pending) Obviously I'll check cyl 3 first. I reseated the plug wire on that cyl. But the random misfire kinda makes me think the overall config is just wrong. Since it runs find at less than WOT, makes me think it's not a completely bad wire or plug. Its still firing, just not under full load. Changing those plugs is a pain, so thought I'd get some input here on what I might try next. Was going to open up the NGK plugs to .040" first, if that doesn't work, I'll put the original plugs back in. Wondering if anyone else has experienced anything similar. UPDATE/EDIT: The TLDR... the recommended plugs and gap work MUCH better than the OEM plugs. It was a damaged plug wire or two that was the issue. Last edited by cjperformance; 07-22-2021 at 11:46 AM. Reason: Update on Solution

07-17-2021, 05:11 PM	#2
Joshinator99 Drives: 2017 Camaro 2SS A8 Join Date: Aug 2018 Location: Petersham MA Posts: 4,750	Are you running headers? The stock plug wires, in my case, got brittle very quickly and weren’t happy coming off...easy to develop a crack IMO. I know some have had success, but not me. Lol Plug could have gotten cracked during install. Did you buy a spare plug you can put in that cylinder? __________________ 2017 Chevy Camaro 2SS A8 Whipple 3.0, Mast Black Label heads, Fore triple in-tank pumps, 112mm TB, LPE +52% injectors, LPE BB HPFP, 15” conversion *1059 WHP/944 WTQ, 9.48@150*

07-17-2021, 08:12 PM	#4
cjperformance Drives: 2017 Camaro SS 50th Anniversary Join Date: Apr 2021 Location: Missouri Posts: 929	Thanks for the input. Good points, all. I'll start with new plug wires. Sounds like the plug gap isn't likely to be the problem based on some of the above, and I could definitely see how the wires could be brittle and damaged.

07-18-2021, 04:54 PM	#5
Chevy1American Drives: 2SS Join Date: Sep 2017 Location: UK Posts: 66	Gap the plugs to .042 thats what i run on my D1X set up

07-18-2021, 05:20 PM	#7
SSUNDVL Drives: 2016 Camaro SS Join Date: Jul 2020 Location: Dallas, TX Posts: 149	Was the car running fine when you swapped the plugs?

07-19-2021, 09:05 AM	#8
cjperformance Drives: 2017 Camaro SS 50th Anniversary Join Date: Apr 2021 Location: Missouri Posts: 929	Ordered some new Granatelli plug wires. Easiest thing to try first. Will update in a week or so once I install them.

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