Misfire readings on cylinder 8 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

V1SIOUS5THGEN · 03-21-2021, 06:26 AM

So I’m picking up misfire readings on cylinder 8 watching misfire counter on snap-on scanner. I’ve swapped coil and wire to different cylinder but still showing misfire. Pulled old plug and it was black on tip. Added new colder plug and week later it’s black as well. What could be the issue? I have bigger injectors and Ecs supercharger plus cam

sdynak · 03-21-2021, 07:04 AM

Would think injector based on what you did so far. Likely leaking. Might see in a pressure test (pressure dropping gradual after pump prime). A compression test would not hurt either.

V1SIOUS5THGEN · 03-21-2021, 07:48 AM

Quote:

Originally Posted by sdynak

Would think injector based on what you did so far. Likely leaking. Might see in a pressure test (pressure dropping gradual after pump prime). A compression test would not hurt either.

Ok. Would you recommend i swap injector to different cylinder first or compression test? Which is quicker?

V1SIOUS5THGEN · 03-21-2021, 08:43 AM

Quote:

Originally Posted by sdynak

Would think injector based on what you did so far. Likely leaking. Might see in a pressure test (pressure dropping gradual after pump prime). A compression test would not hurt either.

Not sure if your tagged when i hit quote on reply

V1SIOUS5THGEN · 03-21-2021, 02:21 PM

Can anyone else chime in on this question please

tartagliazl1 · 03-21-2021, 02:57 PM

check for a cracked plug. some are hard to see. but will cause a misfire, happened to me on the dyno.

V1SIOUS5THGEN · 03-21-2021, 03:12 PM

Quote:

Originally Posted by tartagliazl1

check for a cracked plug. some are hard to see. but will cause a misfire, happened to me on the dyno.

So this occurred with old plugs in it and then i changed to a colder plug and it still shows a misfire on cylinder 8. I pulled that plug as well a week later and it was black as well on the tip. Everything I’m reading leads up to a possible injector leaking but not sure.

tartagliazl1 · 03-21-2021, 03:16 PM

swap the injector to the #1 cylinder and see if it does the same thing to the #1 plug

V1SIOUS5THGEN · 03-21-2021, 04:15 PM

Quote:

Originally Posted by tartagliazl1

swap the injector to the #1 cylinder and see if it does the same thing to the #1 plug

I’m gonna do that but didn’t realize how big of a job it is lol. Do you think that would be the only issue or do a compression test on that cylinder as well?

silversleeper · 03-22-2021, 11:13 AM

Quote:

Originally Posted by V1SIOUS5THGEN

I’m gonna do that but didn’t realize how big of a job it is lol. Do you think that would be the only issue or do a compression test on that cylinder as well?

Needs a rebuild. There is a chance that hard to get to plug got cracked, start with putting in a new plug before pulling the engine for a rebuild. And black on the plugs might want a hotter plug not colder, but that won't fix it here.

RankSS · 03-22-2021, 11:58 AM

Could be a valve spring or ring land.
First step would be a compression test. Then if ok remove the valve cover.
Swapping injectors is not a huge job but I doubt this is the problem.

Greenhornet2 · 03-22-2021, 02:22 PM

swap the coil, and plug wire to a difference cylinder to see if the misfire moves. compression test is quick and easy. test all of the cylinders on that bank it will tell you what normal compression should be. Injector swap would be the last thing I do if all else checks ok. If compression is low pull the valve cover look for broken spring or loose rockers missing trunnion needles.

V1SIOUS5THGEN · 03-22-2021, 04:22 PM

Quote:

Originally Posted by Greenhornet2

swap the coil, and plug wire to a difference cylinder to see if the misfire moves. compression test is quick and easy. test all of the cylinders on that bank it will tell you what normal compression should be. Injector swap would be the last thing I do if all else checks ok. If compression is low pull the valve cover look for broken spring or loose rockers missing trunnion needles.

I’ve done swapped coil and wire and it still showed a misfire on 8. Will do compression test next. Would i not hear a ticking if rocker or spring was loose?

V1SIOUS5THGEN · 03-25-2021, 04:56 AM

So we’ve done compression test and number 8 is about 20 down from the rest of cylinders. Readings were in the 180s on all but cylinder 8 which read in the 160s. They did a blow by and it came back perfect. Spring and lifter look fine as well. They also swapped injectors but misfire counter still shows misfire on 8 ��*♂️ Anything else y’all can recommend checking?

03-21-2021, 07:04 AM	#2
sdynak Drives: 2010 1SS Join Date: Aug 2015 Location: Bayville, NJ Posts: 936	Would think injector based on what you did so far. Likely leaking. Might see in a pressure test (pressure dropping gradual after pump prime). A compression test would not hurt either. __________________ 2010 1SS LS3, Black, 235/250, .621/.615, 114 + 4, Kooks Stepped Headers, 3.91's, Bo White PTB, Flowmaster Mufflers, Cold Air Industries CAI, Apex Scoop & Windshield Washer Relocate, SLP Wheels, Skip Shift Eliminate, Barton Flat Stick, OEM HID/Halos, Dyno Tuned by ECS

03-21-2021, 02:57 PM	#6
tartagliazl1 Drives: 2013 zl1 vert Join Date: Dec 2018 Location: Rochester, New york Posts: 949	check for a cracked plug. some are hard to see. but will cause a misfire, happened to me on the dyno. __________________ 22% lower/ 2.5 upper/ 2” headers/ cat delete/ x-pipe/ 2 gallon x tank/ 100-3 pump/ fic 850/ dsx aux kit/ 103mm throttle body/ RPM 5” intake/ meth kit/ prometh lid injection/FI interchiller/ 160* stat/ ngk-7/ msd wires/ elite catch can/ tsp cam/ Che trunnions/ ported supercharger/ 1/2” lid spacer/ brick mod/BMR toe and trailing arms/ 751hp 757 tq SAE @17.3lb on a loaded dyno.

03-21-2021, 03:16 PM	#8
tartagliazl1 Drives: 2013 zl1 vert Join Date: Dec 2018 Location: Rochester, New york Posts: 949	swap the injector to the #1 cylinder and see if it does the same thing to the #1 plug __________________ 22% lower/ 2.5 upper/ 2” headers/ cat delete/ x-pipe/ 2 gallon x tank/ 100-3 pump/ fic 850/ dsx aux kit/ 103mm throttle body/ RPM 5” intake/ meth kit/ prometh lid injection/FI interchiller/ 160* stat/ ngk-7/ msd wires/ elite catch can/ tsp cam/ Che trunnions/ ported supercharger/ 1/2” lid spacer/ brick mod/BMR toe and trailing arms/ 751hp 757 tq SAE @17.3lb on a loaded dyno.

03-22-2021, 11:58 AM	#11
RankSS Drives: 2010 Camaro SS Join Date: Oct 2013 Location: Saskatoon SK Can. Eh Posts: 365	Could be a valve spring or ring land. First step would be a compression test. Then if ok remove the valve cover. Swapping injectors is not a huge job but I doubt this is the problem. __________________ 2010 Camaro SS RS, Maggie with 3.4" pulley, 60# injectors, ADM dual fuel pumps, ADM Stage 2 Cam with Brian Tooley springs and pushrods, black CAI intake, Stainless Works long tube headers w/gutted cats, ZL1 Diff w/offset bushings, Pfadt lowering springs, Pfadt sway bars, Pfadt solid sub frame mounts, BMR trailing arms and toe rods, Hurst short throw shifter, Painted on Hugger Orange stripes, Forgestar F14 Piano Black wheels, Nitto NT05 rubber.

03-22-2021, 02:22 PM	#12
Greenhornet2 Drives: 2011 Camaro 2SS LS3 Whipple Join Date: May 2019 Location: Connecticut Posts: 1,925	swap the coil, and plug wire to a difference cylinder to see if the misfire moves. compression test is quick and easy. test all of the cylinders on that bank it will tell you what normal compression should be. Injector swap would be the last thing I do if all else checks ok. If compression is low pull the valve cover look for broken spring or loose rockers missing trunnion needles. __________________ Whipple 2.9 CAI ID1050x injectors ZL1 Pump JRE FPCM JMS Voltage booster JRE Rough Idle blower cam BTR .660 springs CHE trunnion kit 1 7/8 Speed Engineering Borla Atak JRE scoop 1.5" lowering springs BMR trailing arms and toe links Cradle inserts 704WHP 603WTQ 93 octane

03-21-2021, 06:26 AM	#1
V1SIOUS5THGEN Drives: 2015 Camaro SS Join Date: Feb 2020 Location: Greer SC Posts: 11	Misfire readings on cylinder 8 So I’m picking up misfire readings on cylinder 8 watching misfire counter on snap-on scanner. I’ve swapped coil and wire to different cylinder but still showing misfire. Pulled old plug and it was black on tip. Added new colder plug and week later it’s black as well. What could be the issue? I have bigger injectors and Ecs supercharger plus cam

03-21-2021, 02:21 PM	#5
V1SIOUS5THGEN Drives: 2015 Camaro SS Join Date: Feb 2020 Location: Greer SC Posts: 11	Can anyone else chime in on this question please

03-25-2021, 04:56 AM	#14
V1SIOUS5THGEN Drives: 2015 Camaro SS Join Date: Feb 2020 Location: Greer SC Posts: 11	So we’ve done compression test and number 8 is about 20 down from the rest of cylinders. Readings were in the 180s on all but cylinder 8 which read in the 160s. They did a blow by and it came back perfect. Spring and lifter look fine as well. They also swapped injectors but misfire counter still shows misfire on 8 ��*♂️ Anything else y’all can recommend checking?