Engine Misfire after recent work - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

SoChrisB · 04-25-2017, 06:40 AM

I need some help since I'm sitting here scratching my head. I did a coil pack relocations, new plugs, wires, zl1 fuel pump, ADM FPCM, and ID 850 injectors. I also went down 2 pulley sizes on my blower, 3.45 gears and a new torque converter. Since the work was done I've been getting P0300 code, undiagnosed misfire. It happens randomly, but mostly while the car is sitting idle or I'm not mashing it. I switched to the NGK BR7EFS plug, but am only at 8.5lb of boost. Could the colder plug be the issue? I'm really at a standstill and can't figure it out. The issue never happened when it was getting tuned, either. I appreciate any help you can provide.

Trob85 · 04-25-2017, 06:51 AM

Has it been tuned since all this was done?

SoChrisB · 04-25-2017, 06:55 AM

Yes.

EDFHOBBIES · 04-25-2017, 07:53 AM

I would say 99% of the time a bad wire especially w headers or bad ground ck all the ground straps.. That's the 1st thing a shop will say.. I would then move to wires along the fuel rails that could be pinched under blower or some other way cut or melted.. then maybe a bad injector.. maybe a faulty coil pack... Those are thing I have encountered maybe one of these will help.

MA2010SS · 04-25-2017, 08:11 AM

Quote:

Originally Posted by SoChrisB

I need some help since I'm sitting here scratching my head. I did a coil pack relocations, new plugs, wires, zl1 fuel pump, ADM FPCM, and ID 850 injectors. I also went down 2 pulley sizes on my blower, 3.45 gears and a new torque converter. Since the work was done I've been getting P0300 code, undiagnosed misfire. It happens randomly, but mostly while the car is sitting idle or I'm not mashing it. I switched to the NGK BR7EFS plug, but am only at 8.5lb of boost. Could the colder plug be the issue? I'm really at a standstill and can't figure it out. The issue never happened when it was getting tuned, either. I appreciate any help you can provide.

Since it's a random misfire and not a specific cylinder misfire I would suspect the plugs might be the issue or the proper injector data was not uploaded into the tune for the ID 850's

hillshooter · 04-25-2017, 10:35 AM

Did you gap the plugs?

SoChrisB · 04-25-2017, 10:40 AM

I did to 0.032.

BigMatt · 04-25-2017, 10:52 AM

Make sure your plug wires are all firmly attached. I had a similar issue. Turned out 3 of my plug wires were barely making contact with the plugs.

SoChrisB · 04-25-2017, 11:07 AM

Quote:

Originally Posted by BigMatt

Make sure your plug wires are all firmly attached. I had a similar issue. Turned out 3 of my plug wires were barely making contact with the plugs.

That was the first thing i did. I wish it were that. Thank you though.

QUICRNU · 04-25-2017, 07:04 PM

I had this issue when I did my friends coil relocate, it turned out that the Harness he bought was a POS and it was randomly misfiring cylinders. I tested every cylinder, every wire, every coil pack, every plug on my car, injectors too..... since it was random, that was the only way I could narrow it down to 100% being the harness.

I decided to pull apart the factory Coil Harness and extended the wires to save him some money. It was easy if you know how to solder and basically free, less Solder supplies and gun.

Good Luck finding it!!

SoChrisB · 04-25-2017, 07:53 PM

Quote:

Originally Posted by QUICRNU

I had this issue when I did my friends coil relocate, it turned out that the Harness he bought was a POS and it was randomly misfiring cylinders. I tested every cylinder, every wire, every coil pack, every plug on my car, injectors too..... since it was random, that was the only way I could narrow it down to 100% being the harness.

I decided to pull apart the factory Coil Harness and extended the wires to save him some money. It was easy if you know how to solder and basically free, less Solder supplies and gun.

Good Luck finding it!!

Thanks not a bad idea. Now it's showing pending p0303 before it throws the p0300. I'm at a loss. I've check everything possible.

swiftkart · 04-26-2017, 11:35 AM

Why did you gap your plugs to .032 with only 8.5 psi of boost? The smaller gap can cause idle misfires, I'm around 14 psi and run .042 with no issues, the only time I have gotten a p0300 code is when I tired .036 gap, went away when I opened it back up, ADM and JRE both say run as big a gap as you can and 8.5 psi isn't preventing spark under boost unless you have other issues, there's a good post on here with both of them stating the gap they recommend and use.

SoChrisB · 04-26-2017, 11:58 AM

Quote:

Originally Posted by swiftkart

Why did you gap your plugs to .032 with only 8.5 psi of boost? The smaller gap can cause idle misfires, I'm around 14 psi and run .042 with no issues, the only time I have gotten a p0300 code is when I tired .036 gap, went away when I opened it back up, ADM and JRE both say run as big a gap as you can and 8.5 psi isn't preventing spark under boost unless you have other issues, there's a good post on here with both of them stating the gap they recommend and us.

That's what the shop gapped them at. Worth a try. I'll mess with that.

swiftkart · 04-26-2017, 07:35 PM

Quote:

Originally Posted by SoChrisB

That's what the shop gapped them at. Worth a try. I'll mess with that.

See Spark plugs for supercharged camaro post #11 and I would go to a TR7ix Iridium plug, much better plug if you are not using them.

04-25-2017, 06:51 AM	#2
Trob85 Svt lol Drives: 2011 ss inferno orange blown Join Date: Jan 2012 Location: Topeka Posts: 2,312	Has it been tuned since all this was done? __________________ plasti dip is not a mod.......and a cold air intake doesn't make you fast!

04-25-2017, 07:53 AM	#4
EDFHOBBIES Dyno Show Queen LOL Drives: 16 SS & 17 ZL1 Both Yellow Join Date: Jan 2014 Location: Houston Posts: 4,345 View My Garage	I would say 99% of the time a bad wire especially w headers or bad ground ck all the ground straps.. That's the 1st thing a shop will say.. I would then move to wires along the fuel rails that could be pinched under blower or some other way cut or melted.. then maybe a bad injector.. maybe a faulty coil pack... Those are thing I have encountered maybe one of these will help. __________________ Kong Ported 2650, Crawford Racing Port Injection, Weapon X 112mm Adapter, NW112mm TB, Livernois Ported LT4 Heads, Lingenfelter GT32 stealth cam, Haltech Elite, and Carbon by Trufiber

04-25-2017, 10:52 AM	#8
BigMatt 2010 Camaro 2 SS/RS M6 Drives: 2010 Camaro SS/RS Join Date: May 2009 Location: Clayton Delaware Posts: 1,218 View My Garage	Make sure your plug wires are all firmly attached. I had a similar issue. Turned out 3 of my plug wires were barely making contact with the plugs. __________________ Forged LS3, FED M311 heads, CAI Inc, ARH 1 7/8, Corsa Xtreme, Taylor Wires, MGW Shifter, Street slayer twin carbon clutch, Tick braided clutch line & speed bleeder, ZL1 Diff Swap, BMR Split drop, Sway Bars, Trailing Arms, Toe Rods, Pro bushing kit, Carslyle racing 15in conversion, Whipple, LPE dual fuel pumps, Rx catch can, Id1300x, Alky Control

04-25-2017, 07:04 PM	#10
QUICRNU Drives: Z06 wannabe Join Date: Feb 2015 Location: Daytona Beach, FL Posts: 1,200	I had this issue when I did my friends coil relocate, it turned out that the Harness he bought was a POS and it was randomly misfiring cylinders. I tested every cylinder, every wire, every coil pack, every plug on my car, injectors too..... since it was random, that was the only way I could narrow it down to 100% being the harness. I decided to pull apart the factory Coil Harness and extended the wires to save him some money. It was easy if you know how to solder and basically free, less Solder supplies and gun. Good Luck finding it!! __________________ Apex Focused

04-26-2017, 11:35 AM	#12
swiftkart Drives: 2010 SS/RS LS3 M6 Join Date: Apr 2011 Location: Kansas Posts: 693	Why did you gap your plugs to .032 with only 8.5 psi of boost? The smaller gap can cause idle misfires, I'm around 14 psi and run .042 with no issues, the only time I have gotten a p0300 code is when I tired .036 gap, went away when I opened it back up, ADM and JRE both say run as big a gap as you can and 8.5 psi isn't preventing spark under boost unless you have other issues, there's a good post on here with both of them stating the gap they recommend and use. Last edited by swiftkart; 04-26-2017 at 07:27 PM.

04-25-2017, 06:40 AM	#1
SoChrisB Drives: 2012 Camaro 2SS/RS Join Date: Aug 2014 Location: Rochester, NY Posts: 597 View My Garage	Engine Misfire after recent work I need some help since I'm sitting here scratching my head. I did a coil pack relocations, new plugs, wires, zl1 fuel pump, ADM FPCM, and ID 850 injectors. I also went down 2 pulley sizes on my blower, 3.45 gears and a new torque converter. Since the work was done I've been getting P0300 code, undiagnosed misfire. It happens randomly, but mostly while the car is sitting idle or I'm not mashing it. I switched to the NGK BR7EFS plug, but am only at 8.5lb of boost. Could the colder plug be the issue? I'm really at a standstill and can't figure it out. The issue never happened when it was getting tuned, either. I appreciate any help you can provide.

04-25-2017, 06:55 AM	#3
SoChrisB Drives: 2012 Camaro 2SS/RS Join Date: Aug 2014 Location: Rochester, NY Posts: 597 View My Garage	Yes.

04-25-2017, 10:35 AM	#6
hillshooter Drives: 2015 Camaro SS commemorative Join Date: May 2015 Location: Utah Posts: 425	Did you gap the plugs?

04-25-2017, 10:40 AM	#7
SoChrisB Drives: 2012 Camaro 2SS/RS Join Date: Aug 2014 Location: Rochester, NY Posts: 597 View My Garage	I did to 0.032.