Misfires 2016 Gt procharged Please Help!!

[Haddama]

I have a 2016 procharged gt. After putting roughly 12k miles on the procharger I started getting misfire codes. The first codes were for P0304 and P0307. I decided to change the spark plugs. I drove 200 miles on the new plugs and misfire codes came back, but this time they were P0300 and P0304. At this point I put a multimeter on the coils and injectors. They all passed the test with the multimeter. I found a lot of information on line about IMRC going bad in these cars. I thought that might be my problem. So, I bought a 2018 intake and locked out the IMRC. I have the canned procharger tune and just deleted the IMRC from it. I drove the car around 200 miles again and then started getting misfire codes again. They again were P0300 and P0304. At this point I cleaned and pulled the MAF and intercooler. The intercooler did have a minimal amount of oil in it. I will be installing a catch can soon. After driving another 200 miles, the same codes came back (P0300 and P0304). A mechanic told me that my crank bolt was a little loose. We tightened the bolt, but I still get the same 2 codes. The car keeps a steady vacuum of 15 psi at idle. The mechanic told me that the fuel trims look great. He also told me that he did a compression test and everything was fine. Is it possible for a coil pack to be bad even thought it will pass the multimeter test? Would a loose crank bolt cause a misfire? Does the crank maybe need to be "relearned"? Somebody please help me figure this out.

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[Grimace427]

Swap the #4 coil with #3 and see if you get a P0303 code. P0300 is a general misfire.

 

[Haddama]

Swap the #4 coil with #3 and see if you get a P0303 code. P0300 is a general misfire.

Swapping the coils is my next move. Can the 4 cylinder be the sole cause of the p0300 also?

 

[Grimace427]

Swapping the coils is my next move. Can the 4 cylinder be the sole cause of the p0300 also?

That's not really the right way to think about it. General misfires can occur for several reasons including bad gas, super low temps, super high temps, and many more. Best bet would be to use a scan tool that can show active misfiring if you indeed have a real misfire.

 

[Haddama]

That's not really the right way to think about it. General misfires can occur for several reasons including bad gas, super low temps, super high temps, and many more. Best bet would be to use a scan tool that can show active misfiring if you indeed have a real misfire.

Thanks for the information. The mechanic also did a power balance test and couldn't determine a misfire from that test. I'm really at a loss. Do you have any idea what may be causing a "fake " misfire? I'm thinking I must have something going on with cylinder 4 since i keep throwing that code.

 

[Dr. Norts]

Swap the coil packs from trouble cylinder to a known good cylinder and see if the misfire follows the troubled pack. If it does then it's the coil pack. If it doesn't coil pack is good.

Also check your grounds. If any look suspect or corroded clean them.

 

[Haddama]

Swap the coil packs from trouble cylinder to a known good cylinder and see if the misfire follows the troubled pack. If it does then it's the coil pack. If it doesn't coil pack is good.

Also check your grounds. If any look suspect or corroded clean them.

thanks. What specific grounds? the coil connector grounds?

 

[Dr. Norts]

thanks. What specific grounds? the coil connector grounds?

Yeah I would check their connections, maybe one has loosened up or has a poor connection to the engine/body.

 

[JPSTANG]

Simple question, what did you gap your plugs to?

 

[Haddama]

Simple question, what did you gap your plugs to?

I’m at 30 now. I started at 35 per the Procharger manual. Procharger tech support recommended 30

 

[ugstang17]

It wouldn't hurt to try regapping to .028 to see if that helps, at least on #4. How heavy a drag on the feeler gauge can play a role in the air gap from one person to the next. Some may be scratching their heads on this statement. What does he mean by heavy drag?

In the machine tool trade when gauging anything the final reading (or go/nogo in a machining process check) fully depends on the feel of the machinist.Not all machinists (or people) have the same touch/feel. The same applies to gapping plugs. E.G. if you are gapping a plug, and you gap it so thatyou just barely feel the wire gauge or feeler gauge slip past that gap will be different than a person setting the gap and all but forcing the gauge through the gap in his/her process. There will be a difference. I try to get an answer from tuners on this topic when told what to set the gap to. They know based on how they gap plugs what works based on how they are gauging the gap (light or heavy drag). The strap can flex if gauged too heavy causing the gap to be less than on a light gauge feel. This could equate to 1-2 thousandths.

Second and this is according to old timer mechanics I know, and may not apply to modern day plugs, but with heat cycles of the engine the gap will naturally want to open up a bit after a period of driving. This has not as much to do with the electrode burning away as it does just the properties of the steel in the plug causing this to happen....if there is any fact in it. So rule of thumb would be to gauge a bit heavier I am told to compensate for this.

You could try just regapping the #4 cyinder plug to see if that helps resolve the 0304 code. Try .028" using your technique. The problem may be this simple. However being you changed plugs after the problem arose after 12000 miles and came back shortly after changing the plugs indicates this may only eliminate a plug(s) as a/the potential problem.

Don't forget to swap coils as mentioned either. Again while no change may be seen it eliminates another possible fault. Troubleshooting is about eliminating probable faults.

Good luck.

 

[Haddama]

Thanks for all the information. I have swapped coils. I’m waiting to see if the codes show back up. Do you know if a coil can pass a resistance test and still be bad? No one has answered that for me.

 

[Dr. Norts]

Thanks for all the information. I have swapped coils. I’m waiting to see if the codes show back up. Do you know if a coil can pass a resistance test and still be bad? No one has answered that for me.

Yes it totally can. Resistance can measure fine yet the output voltage or output pulse / waveform could be having issues. Also if it has a bad / loose ground you won't find this by just resistance testing the coil.

You'd need an oscilliscope and some electrical know how to insert your probes into the coil circuit and monitor what's going on as they fire and compare this vs another known good coil. Even then you'd need to know what kind of waveform your expecting to see.

Swapping coils is the quickest way to rule out a bad coil without using a bunch of expensive electrical test equipment.

If the issue doesn't follow the coil and stays on cylinder 4 your coil is good and I'd start looking more at cylinder 4. Trace the wires for coil plug #4 and see If you can find any issues with the wiring / ground / pinched wires. Trace from the coil plug as far back as you can.

When are the misfires happening? High or low rpm? High load? Low load?

You could even try indexing plug #4 as a last resort and see if that helps. Maybe your getting spark blowout.

 

[Haddama]

Yes it totally can. Resistance can measure fine yet the output voltage or output pulse / waveform could be having issues. Also if it has a bad / loose ground you won't find this by just resistance testing the coil.

You'd need an oscilliscope and some electrical know how to insert your probes into the coil circuit and monitor what's going on as they fire and compare this vs another known good coil. Even then you'd need to know what kind of waveform your expecting to see.

Swapping coils is the quickest way to rule out a bad coil without using a bunch of expensive electrical test equipment.

If the issue doesn't follow the coil and stays on cylinder 4 your coil is good and I'd start looking more at cylinder 4. Trace the wires for coil plug #4 and see If you can find any issues with the wiring / ground / pinched wires. Trace from the coil plug as far back as you can.

When are the misfires happening? High or low rpm? High load? Low load?

You could even try indexing plug #4 as a last resort and see if that helps. Maybe your getting spark blowout.

Thanks for all the information. The codes are showing up during normal daily driving. Low rpm low load. The engine sounds great though. You can’t tell from the sound of the engine that there are any misfires. Could the number 4 also cause the p0300?

 

[ugstang17]

Thanks for all the information. I have swapped coils. I’m waiting to see if the codes show back up. Do you know if a coil can pass a resistance test and still be bad? No one has answered that for me.

Yes it can as stated above. The only way to know for sure would be under a full saturation test. While I deal mostly with motors and transformers which I can test with a megger inducing 100-500V into the coil to saturate it and measure the insulation of the winding to ground, I am not sure what the process would be for a COP though the theory is the same.

Don't forget to inspect the rubber boot for tears in either case. A pin hole in the boot would allow voltage potential to find its way to the engine block rather than through teh spark plug.

Just as a thought you may wish to share the brand of plug you were running as well as the brand of plug you run now. I'm FI but not running a PC. So maybe a Pro Charger owner may have a suggestion in the event there may possibly be a better spark plug option for your setup in the slim event that could be the problem. All a part of troubleshooting....ruling out the distracters.

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