2012 Suburban Misfire #5 drama

[2015TahoePPV]

Will see about checking deeper into harness if I can find the schematic, shooting power and ground at injector harness and coil were solid? If I find connector and pins on ECM I could take off and shoot Ohm readings looking for jumping around when wiggling harness wear worn. Got noise light for injector plug coming in two days.

There’s diagrams on the LS swaps site, that’s where I found mine. I’ll see if I can locate them for the ’12.

 

[2015TahoePPV]

Injector Schematics:

 

[rdezs]

At this point it might be worth putting the original injectors in....

 

[Dustin Jackson]

@rdezs He said the problem started before he replaced the injectors and that didn't fix it

 

[Keiterburb]

Noid light on injector 5 was flashing at steady pace without problem and when plugged back in the miss decreased again by half of what was evident when unplugged. Time to start shopping AFM delete kits with a tune I’m guessing

 

[Keiterburb]

Correct, problem was not a symptom of any change. All has been there for some time driving off and on, not my daily, waiting for time to work on it between other work. Always have something to work on here.

 

[Dustin Jackson]

@Keiterburb Texas Speed and Performance has good kits but I say take it slow and find the problem before firing off a solution.

If you’re handy enough to open it up and find the smoking gun yourself that would help define which path you should take. When my lifter failed I didn’t find the smoking gun until I pulled the lifters, every part leading up to that was in great condition. Getting the heads and cam out is easy enough and should provide all the information you need.

 

[rdezs]

Be careful when looking at a delete "kit".... Not only can you put together your own from getting each piece individually, you'll know the parts you got are correct. I did so, and saved a couple hundred dollars. Often these kits that are marketed have aftermarket parts severely marked up. For example, at least as of a year ago, you could not get the genuine Delphi LS7 lifters with a gold retaining clips in any kit being marketed. I hate the name any vendors, so I'll just say there's one named after a state, that tried to sell me one for an L94 and the part number for the camshaft included in the kit was for a 6.0.. the left and duration were slightly less than what the OEM 6.2 calls for.. and the lifters in the kit were not genuine LS7. Pieced together my own kit, using the proper L92 OEM camshaft. Ended up saving myself close to $200, and that was with me going for the arp cylinder head bolts. (Not studs)

 

[Airman68]

Be careful when looking at a delete "kit".... Not only can you put together your own from getting each piece individually, you'll know the parts you got are correct. I did so, and saved a couple hundred dollars. Often these kits that are marketed have aftermarket parts severely marked up. For example, at least as of a year ago, you could not get the genuine Delphi LS7 lifters with a gold retaining clips in any kit being marketed. I hate the name any vendors, so I'll just say there's one named after a state, that tried to sell me one for an L94 and the part number for the camshaft included in the kit was for a 6.0.. the left and duration were slightly less than what the OEM 6.2 calls for.. and the lifters in the kit were not genuine LS7. Pieced together my own kit, using the proper L92 OEM camshaft. Ended up saving myself close to $200, and that was with me going for the arp cylinder head bolts. (Not studs)

I'm a pretty capable mechanic. What would you say your parts cost and how much time did you have into it? Also, did you get your computer reflashed? I bought a truck from a guy many years ago, and he did these and said he reflashed the computer to delete the AFM stuff after installing the parts.

 

[j91z28d1]

yeah, you'll need it turned off in the tune when deleted.

few different ways, cheapest is sending the ecm off to have it turned off, I believe it's 50$ or so. or find someone with hptuners willing to do it for the credits. I believe it's 2 at 50$ each. or 3rd would be a full tune, mail order like most here or local tuner shop. 500+?

definitely try to get this real ls7 lifters. with the gold internal rings. there's a thread around here somewhere with a seller, since they are getting very hard to find.


I. haven't had to delete mine yet, but for a decent idea of all the odds and ends, I was looking over guys stuff. he's got some good. youtube videos about afm as well.

AFM Delete Kits | Crazed Performance

Best place to get Full AFM DOD delete Kits for your GM trucks.

www.crazedperformancerepair.com

 

[rdezs]

I used the Diablo predator to turn off the AFM, and make a few other adjustments like tightening up the shifts for longer transmission life. The total cost of how much you spend really depends on how much you want to do "while you're in there." For example, since I had my heads off which looked good, I figured why not have them checked out by my local cylinder head guy.... Cleaned up, valve job, all the guides are okay but new seals. With the front differential out and the oil pan off, you're looking right at the back of your power steering hoses on the back side of the pump..... It'll never be so easy to replace those again. New ACDelco starter as preventative maintenance since it's out anyway..... And the crankshaft position sensor is right above the starter, so might as well do that as well. The list can be extensive once you get down that rabbit hole, lol. Stuff like that really isn't necessary technically, but as this is my wife's daily driver I figured it was be a good idea.

I've been getting the genuine LS7 lifters from Michigan Motorsports. And make sure you use genuine GM lifter trays as well. Below is a picture off there website showing the gold retainer....

 

[Airman68]

I used the Diablo predator to turn off the AFM, and make a few other adjustments like tightening up the shifts for longer transmission life. The total cost of how much you spend really depends on how much you want to do "while you're in there." For example, since I had my heads off which looked good, I figured why not have them checked out by my local cylinder head guy.... Cleaned up, valve job, all the guides are okay but new seals. With the front differential out and the oil pan off, you're looking right at the back of your power steering hoses on the back side of the pump..... It'll never be so easy to replace those again. New ACDelco starter as preventative maintenance since it's out anyway..... And the crankshaft position sensor is right above the starter, so might as well do that as well. The list can be extensive once you get down that rabbit hole, lol. Stuff like that really isn't necessary technically, but as this is my wife's daily driver I figured it was be a good idea.

I've been getting the genuine LS7 lifters from Michigan Motorsports. And make sure you use genuine GM lifter trays as well. Below is a picture off there website showing the gold retainer....

I 100% get doing it while you're in there. I would do the same thing. I'll have to look into the specifics what needs to be done. I have done head work before and would certainly have those repaired while out. Fortunately, mine is running good now (knock on wood) but it's always nice to have a plan so you're not caught off guard when it happens.

 

[Doubeleive]

Noid light on injector 5 was flashing at steady pace without problem and when plugged back in the miss decreased again by half of what was evident when unplugged. Time to start shopping AFM delete kits with a tune I’m guessing

@198k my next test would be a backpressure test, then if that doesn't reveal anything I guess crack it open
backpressure test is easy enough to do with some basic hardware and a gauge
unless there's a better idea......
I am speaking from the perspective of I went the route of replacing lifters to then finding out a clogged cat was (at least) a good part of my issue.
still kind of mad about it.......at myself
my case was more severe I had multiple unexplained misfires and rotational noise, loss of power, but didn't fully diagnose the possibility of a clogged exhaust

 

[Geotrash]

I'm a pretty capable mechanic. What would you say your parts cost and how much time did you have into it? Also, did you get your computer reflashed? I bought a truck from a guy many years ago, and he did these and said he reflashed the computer to delete the AFM stuff after installing the parts.

I had Blackbear tune mine and it's been great. Here's my thread on it for my 2012 6.2 if you're interested. I'm also very happy with the cam I chose. Smooth idle and great power down low.

https://www.tahoeyukonforum.com/thr...nali-6-2l-cam-swap-thread.121671/post-1616690

 

[Airman68]

I had Blackbear tune mine and it's been great. Here's my thread on it for my 2012 6.2 if you're interested. I'm also very happy with the cam I chose. Smooth idle and great power down low.

https://www.tahoeyukonforum.com/thr...nali-6-2l-cam-swap-thread.121671/post-1616690

I just skimmed over some of your post, just awesome. Thanks for the info. I will be referring to it several times I'm sure.

 

[Geotrash]

I just skimmed over some of your post, just awesome. Thanks for the info. I will be referring to it several times I'm sure.

Glad you found it useful. Happy to be a resource for you as you go, also.

 

[Keiterburb]

@198k my next test would be a backpressure test, then if that doesn't reveal anything I guess crack it open
backpressure test is easy enough to do with some basic hardware and a gauge
unless there's a better idea......
I am speaking from the perspective of I went the route of replacing lifters to then finding out a clogged cat was (at least) a good part of my issue.
still kind of mad about it.......at myself
my case was more severe I had multiple unexplained misfires and rotational noise, loss of power, but didn't fully diagnose the possibility of a clogged exhaust

Would the post cat O2 sensor 2 waveform show a bad/clogged Cat? Just learning how to read the waveforms so I can take another test run. Last test after warming engine and viewing at idle the banks had completely different downstream sensor waveforms

 

[Doubeleive]

Would the post cat O2 sensor 2 waveform show a bad/clogged Cat? Just learning how to read the waveforms so I can take another test run. Last test after warming engine and viewing at idle the banks had completely different downstream sensor waveforms

@Fless

 

[j91z28d1]

I've honestly never graphed my rear o2s but I believe they are supposed to be pretty flat. but how much so, I don't know.

 

[Dustin Jackson]

I don’t know a lot but shouldn’t both banks look similar? Is cylinder 5 on bank 1?