can somebody tell me, whats wrong with this. randomly getting misfire on #3 n #7. New sparks plugs new wire. swap coils too. lifters replaced 100km ago.
can somebody tell me, whats wrong with this. randomly getting misfire on #3 n #7. New sparks plugs new wire. swap coils too. lifters replaced 100km ago.
I'm afraid I can't be much help but I have a question for you. Where did that tune come from? What make/model was that L83 tune file from? I've compared it to my l83 tune and there are more differences than I was expecting.
Is this a stock vehicle? Have you checked your grounds?
My tune file from a 2016 GMC Sierra with an 8 speed:
2011 Jeep Wrangler Unlimited Rubicon
2016 L83/8L90 Gen V engine/transmission
E92/T87 ECM/TCM
I checked everything mine is 2016 Yukon 5.3l 6l80
Definitely something funny on bank 1, looks like a misfire. Make sure you plug wires are fully seated on both ends. Sometimes they can be a little tricky to snap on all the way. If that's not it do a quick compression check
Hmm i am thinking to put new OEM wires. But not sure what could be the reason may be carbon build up because i double check every thing and only #3 and #7 giving me trouble
I see DOD is disabled in the tune. Did you replace the lifters/cam too?
I ask because I picked up my engine cheap because it had a bent push rod.
I don't believe cylinder 7 is part of DOD but I believe 3 is. It isn't a common problem I guess, but the DOD engines can bend push rods when the DOD lifters start malfunctioning.
2011 Jeep Wrangler Unlimited Rubicon
2016 L83/8L90 Gen V engine/transmission
E92/T87 ECM/TCM
No, DOD cylinders are 1,4,7,8, i replaced lifters, inspected all push rods were perfectly fine. Yes i am using DOD cam and Dod lifters just put 100 kms ago. I will try to replace spark plugs on 3 and 7 main source of misfire is #3 and misfire #7 comes occasionally. Before that I had P0301 misfire on #1 because of failed lifter. After repair i was loging and find out misfire on 3 and 7. Do you think i need to check torque again on under valve cover on Bank 1?
DOD are 1,7,4&6. You're sure you got the lifters back on the right cylinders? They are bad to bend pushrods even on the non DOD ones. The DOD are worse because of the sudden pin latch and punch to the rod each time you start the engine.
Are you sure coils and injectors are plugged up correctly? Forgot which ones it was, but there are a couple that are easy to reverse.
Were springs checked for cracks and proper operation? How bad carboned up are the valves? Bad carbon can cause valves to not seat or the DI fuel burn to not happen correctly.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
Have you looked at the ground for the coils. There was a bulletin on it and my truck at 13k miles had issue. I replaced ring terminals with better ones,cleaned it and bolted it down worked perfect. then later added a larger ground on top and truck freaked out misfire and many codes. moved larger ground up to head and all codes gone. Something odd. also did the Bulletin No: PIT5405B Date:Aug-2016Originally Posted by Baljit
Is what you're referring to in the beginning the same bulletin? Seems like it wasn't if I read correctly. Do you have the bulletins by chance to post? That is interesting that just moving the ground fixes the issues.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
oh sorry no i don't have the bulletin on the coil grounds. They are on front of the block easy to get to. they go bad. but my issue came from a 1/0 cable ground from the 2nd battery on top of them. so the 2nd battery ground was moved up to the head. all issues and codes gone. aluminum(block),Coated (ring terminals), copper(1/0 cable) maybe a issue there or the different ground paths. IDK
as far as that bulletin it is a huge issue and may are needing replaced cables. so after speaking to some people i added 2 extra cables to the stock battery. high quality 4ga. 4ga because negative cable must go though the sensor. the positive is just small wire off the post to the 1st stud.
Did you use dielectric grease on the sparkplug caps? If so, try swapping the injectors around to good cylinders and see if the problem follows. I'd follow up with a compression test and valve spring inspection.
I am waiting for OEM wires, yes used dielectric grease all connections seems tight and nice otherwise truck is running good so far but getting misfire occasionally, i double checked ground at the back of head. Double check all wires, coils, spark plug are new acdelco check gap also .40. Will replace wire with OEM. I am getting misfire on cold start and while on highway speeding on higher RPMs otherthan that no issue fuel mileage is good too but still i need to find out why is this happening.
If I remember the battery ground is on the engine then another ground to firewall from back of driverside head. but the 2 coil grounds are lower driver side on a 13mm bolt. there is also a battery ground to frame on passenger side that is a issue. i had missfires with coil ground and one burned wire. just don't want to buy custom $180 wires for that one spot.
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