712-304-2812-*****

So, i got a mail order tune, truck is running lean, nothing major kind of expected with out wideband or dyno tuning
MY ISSUE
I have multiple random missfires, mostly #6, when it misses, it is dead, sometime it does not miss. number 2 misses the next most, then the other two on the right bank miss some.
the left bank, has very little missing going on, and i can suspect that maybe they will miss some because of the rest that is going on.

Right bank plugs are black, left bank are good and brown
coil plugs and wires are not the issue
knock sensor code came up, but i would not think it would direct its attention to one bank, and more so one or two cylinders

I swapped o2 sensor from left to right with no change.

Can tuning cause an issue like this?
I think the maf is ruled out since the miss is pretty well dead when it does it and subject to one side mainly
injector scaling? map scaling? maf scaling? im no tuner so im not positive, but i doubt it.

I will swap injectors tomorrow and hope the miss follows the injectors- if not, what else? head gasket? i wouldnt think so, if combustion was going between cylinders i would have miss on 6-8 or 4-6 i would think. motor has an hour of run time.

I have ls3 injectors and spliced connectors onto factory harness, i re did the connection on 2 and 6 with no change, so i do not think that owuld be an issue.
main coil plug harness? moved it jiggle it, no change while monitoring misses

about 2k rpm and up it doesnt seem to miss


I kno this is a mile long, just looking for insight as im going to have a couple hours to work on it in the morning

SOMEONE CAN CALL IF HAS SOME GOOD INFO OR A TEXT WHATEVER
712 304 2812

 

How did you rule out the coils/plug wires? If one whole side is black, that means it's getting fuel but not burning. My guess is that it's something electrical either the coil harness or something else. A timing light might be able to tell you if a cylinder isn't getting spark, but I've heard they need very little voltage to emit light so it may still flash with a weak coil/connection. Are you getting any rich/lean codes? More info on your harness or setup might help.

 

Well i mean i have swapped coils and plugs from cylnider to cylinder and with other ones i have sitting around.
Im getting LEAN CODES bank one and two
fuel pressure is good, 58-60 WOT
o2 sensors are not new, but no codes and ran and worked good in other truck i had them in.
#2 started missing dead about as much as 6 now.
I did a crank relearn with no change, i can hear the injector click with stethescope when it is missing, but im going to swap them out here in a little bit

 

Swapped injectors, still #6 and #2 main misses
must be intake or internal or tuning

 

The lean condition makes me think you have a vacuum leak, but that doesn't make sense if the passenger side plugs are black. Have you disconnected the PCV, is your intake new or used? I've read a lot of threads of random issues that are caused by bad O2's where they are getting unexplainable misfires. Does it seem to run better before it switches to closed loop(first 2 minutes of cold start)? That would indicate something with the O2's since the computer isn't reading them at startup.

 

Now that you say that, it does seem to always run better in open loop, but i thought when i first was diagnosing it i had it stay in open loop but i will definitely have to double check. I heard vette o2 sensors are a good sensor especially if running like an open header? Also will putting a turn down on the header help the o2 read? i did notice one of my o2 reading jumping some, i will have to look at the log again

Thanks

 

So I havbe had no time to work on it, but before i put new o2 sensors on maybe a few questions can be answered
Should i ge wide bands so i can further tune it better?
will putting turn downs on the headers be a smart idea?
are the vette o2s better or so i read?
does tuning out of 2008 chevys flash onto my ls1b ecm?

 

Can you feel it misfire, or does it just show up on the scan tool? Do you have catalytic converters on the vehicle? A stopped up cat can cause a misfire isolated to one bank. To the basics, you need to check injector pulse with a test light or noid light. Then you need to verify that you have ignition spark with a spark tester. Also need to do a compression test. Misfires are usually pretty easy to isolate.

 

Take an infrared temp gun and check the temp of each exhaust primary to see if some are alot cooler than the others. Those will be the problem ones. Disconnect your 02 sensors so it stays in openloop and see how it runs.

 

I have EFI Live and a mac mentor so i can make it stay in open loop with them and thats where im going to start next
Ive checked temp on them and they are all relatively close
i have swapped inejctors and re soldered injector connectors
I can definitely feel the miss
while running ive pulled plug wire and spark is good, i have swapped plugs coils and wires
Very busy at work and am remodeling the new house so time to work on it is far and few between hours

Thanks for the input, hopefully i can hold it in openloop and it doesnt miss like it does and that will probably answer a lot of it

Always open to ideas, i have logged it too if anyone wants to see it and or the tune that is on it.

Would poor maf or map tuning cause any of it? since the 6.0 is 1 bar and 6.2 stuff is 2 bar? correct me if im wrong, i dont do gas tuning and am not super familiar, just had a rough tune made for it so far.

 

I feel like an idiot, the right o2 sensor was plugged into the front o2 plug, suspecting that has something to do with it, switched it to the correct plug and still doing it.
from it running how it was, would that cause the o2 sensor to foul out plug up not work?
any o2 sensors better than others?
just running open headers right now til i get it running right and get exhaust, no cats will be used.