2016 Denali 6.2L Fuel Trims

[svl208]

Attachment 140824Attachment 140825

2016 GMC Sierra Denali 6.2L / TSP .610 Cam / .665 TSP Dual Springs / 0 Degree Cam Phaser Lockout

AFM/DOD Delete & Current Tune - Done by someone else.

This truck is driving me crazy!

It came to me with a .540 Comp Cam and a few broken valve springs. I installed a TSP .610 cam, .665 valve springs, and did the 0 degree cam phaser lock out. The truck is still on the previous .540 cam tune done by someone else. I was told that the short term fuel trims are screwed up. I went thru and found a couple things and corrected them but I don't know if I corrected the issue causing the irregular short term fuel trims.

If anyone has the time to review the log (It's a lil long) and give their input on the fuel trims. I also included the tune that the truck is currently running. I'm not a tuner by no means. Once I get the fuel trims corrected then it can get tuned by someone that knows how to tune.

Any input would be greatly appreciated.

Thank you

[GHuggins]

Use advanced to attach the log and tune files. (advanced - manage attachments)

Entire list of mods too including any deletes.

[svl208]

Oh man! My apologies.

I'll get the tune and log attached properly on my lunch hour today.

And get a complete list of mods.

Thank you.

[svl208]

2016 GMC Sierra Denali 6.2L

Done by someone else:
AFM-DOD Delete / .540 Comp Cam / Comp Cam Valve Springs / Current Tune

Vehicle got DTC's P06DD

Done by me:
Replaced Oil Pump w/ OCV Solenoid (OE)

Vehicle still wouldn't run it would go into reduced power mode. I found 4 or 5 broken valve springs causing misfires.

I was brought TSP .665 double valve springs to install (I wanted .600 valve springs at most). I installed the .665 double valve springs and the vehicle was running fine.

2 or 3 weeks later the vehicle come back with a hard ticking sound. Misfire on cylinder #7 only. I pull the valve cover and the valve springs all look good. Pulled the rockers and springs and found one of the #7 cylinder lifters crushed worst than I've ever seen lifter get crushed. Lol.

Then I was brought a TSP .610 cam to install. I got it installed and did the 0 degree cam phaser lockout that came with it as well.

Vehicle would start, run like crap, die, and then would restart. I was also told the short term fuel trims were screwed up. I started looking into why and figured out that i didn't install the high pressure fuel pump at TDC exhaust stroke. I put everything together at TDC compression stroke. I got that corrected and that where the work I did and the work I know of ends.

I just need someone who knows more than me to take a peek at the fuel trims and determine if it's to the point to send to the guy who's gonna tune it. Vehicle still kinda runs like crap and does not restart after idling.

Thank you.

[GHuggins]

You've technically got a 18% fuel trim split bank to bank. Make sure you don't have a miss on bank 2 or vacuum leak or something like that for them to try and blame you for. It could even be a bad injector being a 6.2 liter.

[svl208]

That's not was I was hoping to read. Lol!

I am getting blamed for it, not in a bad way but I did do the work. It's my nephews truck and weather it's his vehicle or anyone else's and I did the work and I want to be the one to correct it. I want to find out what I did wrong or what I missed and be the one to fix it. I can't have anyone out there sayin they fixed my f&$# up. Lol.

I'm gonna do another scan and add the misfire pids to see if I can see a miss fire. That might help narrow down a bad injector too.

I got home from work early so I have some daylight to look for any vacuum hoses not connected. Re-check the intake manifold too.

As far as a bad injector? Would an injector balance test show a bad injector?

One more question? and I know this is a dumb question! I haven't been resetting the fuel trims this whole time. Should I be resetting them?

Thank you for your input and your time.

[GHuggins]

It would probably be easier to just kill long terms under the O2 controls that way you could rather easily see the bank to bank fueling error. You can kill long terms via the speed and temperature settings.

I've seen 6.2 injectors both stick on - really not good - engine will die while idling if this happens as all rail pressure goes with the stuck open injector AND stick off or shut. It'll just show as a miss at that point. Now one restricted is a different story. May show miss. May not. This kind of a fuel split is usually from a dead miss via wire, plug or injector. Should have inj circuit codes if unplugged. I honestly didn't check your log for dtc's.

[svl208]

I visually looked it over for vacuum leaks on the passenger side. I didn't see anything?

I set up the scanner with mis fire pids. Plugged it in and started the truck. Pinche HPTuners VCM Scanner went loco. I couldn't scan or do a log. Instead of waiting for the laptop and scanner to load up again. I plugged in a lil scanner I have to check for mis fires. #1 had the most. #8 and #6 had a few.

It does die idling. And then won't restart.

Now that it has died idling I have to wait for anywhere from an hour to four hours before it will start again so I can log it.

I'm gonna kill the limg term like u suggested. I think I seen where to turn it off before the scanner went loco. Lol.

Thanks for the input. My head is old and slow. Plus I'm not a tuner. It helps ALOT getting some input and direction.

Thank you.

[svl208]

I did scan it earlier. DTC codes

P015B O2 delayed response
P015D O2 delayed response
P06DD - This one clears once I can drive the truck.

[GHuggins]

You'll have to log a lot more pids to know if it's an injector sticking causing the stall. Rail pressure and rail pressure desired. Ignition timing and torque pids would be nice too on top of the misfires.

Giving throttle won't re-fire?

[svl208]

Na man.

U can give it a lil, 15%, 25%, 40%, or any amount of throttle. Damn thing won't refire after it dies.

My lil nephew burnt the starter cranking it so much and so long. Lol!

What pids would help me narrow down an injector? I did have the injectors and rails out of the vehicle. If it's an injector I'd almost buy it for my nephew to get this thing running.

I have been watching desired fuel pressure, fuel pressure, and fuel rail pressure.

A buddy also lent me his scanner and his will split fuel rail pressure. It will also do that injector balance test.

Thanks!

[GHuggins]

Rail pressure when it won't fire. Doesn't look like any of the torque model was dialed in either. The tune can cause stall issues but will usually restart and you won't have the bank to bank issue this bad either.

[svl208]

I got rail pressure as a pid.

After it sits for a while. Anywhere from an hour to four hours it will start. The truck Idles like caca (poop). Lol. Fuel trims are what u seen. Once it dies of it's turned off with the key. The dang thing won't start for s#%^. And yes that bank to bank issue is what's got me? Not just a cylinder but a whole side of the engine. The whole bank. I've went over the truck and in my head of what separates the whole bank? O2's, fuel rails, Intake Gaskets are new and ain't pinched or rolled, I had the hogh pressure Fuel pump on TDC top dead center. I corrected that to TDC exhaust stroke.

Makes me think did the head Gasket not seal or some wierd s$&%? But if that was the case coolant would be in the oil?

It has my brain in a wrap goin over the same things and checking the same things. It does help to have another brain with ideas.

Thank you.

[svl208]

Alight after letting it sit for roughly 2 to 3 hours.

The truck starts like it should. I was able to get a log. I attached it for review. I did turn off the the long turn fuel trims in the special function tab as you suggested. Man! Now with the long terms not coming in to help the shorties it can really be seen how out of whack the short term fuel trims are. I added a few other pids idk if maybe any of them help?

It don't look like my buddies scanner will do that injector balance test? But i'm not totally familiar with his scanner.

If you have time review the log and see if you see anything? Other than crappy short term fuel trims. Lol.

Let me know if you have any other suggestions?

Thank you.

[GHuggins]

Almost looks like in that one bank 1 is over fueling and because bank 2 can't add enough fuel it's failing the O2 fuel control test which is why it defaults to bank 1's fuel control and you see bank 2 stay lean. Injectors aren't that expensive if your nephew wants to install a low mileage new used set or whatever. It'll either be that or O2's. Hard to say on that one. Were the cats damaged any with the engine failure? I never see bank 2's post O2 lean out much. Bank 1's leans out a touch when the test runs. Might need to rev and hold just to get good data around 1500 or so rpms. Hard to say without doing a bunch of test. Cranking can be tune related, but usually they fire. Need to log pulse widths for that one to see if it's even trying. May take a few times running to see any dtc's if there are any related to it.

[svl208]

Sorry it took a bit to reply.

As far as I know there was no damage to the cats.

Tomorrow I'm gonna swap O2's and see what happens? If it is O2 related that should hopefully change the bad fuel trims to the other bank. If the fuel trims stay on the same side that would rule out O2's. I think?

At that point I guess it's an injector?

I just hate spending money on shotguning parts at it.

I'd like to confirm an injector or injectors as bad.

Is it possible to swap fuel injector rails? That would confirm an injector issue.

I'll post the results after swapping O2 sensors tomorrow.

Thanks again for you input!

[GHuggins]

You can swap the injectors themselves along with the precat O2's. I've had customers do that before for this very issue. It's always come back to the injectors being the problem FWIW unless he's running junk AM O2's. Seems injectors are bad on the 6.2's for all sorts whereas the 5.3's just over fuel in general...

[svl208]

Check this out!

Swapped bank 1 and bank 2 precat O2 sensors and it looks like the problem stayed on the same side? I think? Lol.

As for swapping injectors to confirm it's an injector problem? What else could it be?

Is there anything else it can be?

If it's fairly certain, 70% or higher that its an injector problem than why swap them to confirm?

If I'm in there to swap them? I might as well replace them?

Hit me with ur opinion of it possibly being something else? and also of which injectors to replace some or all?

I attached a log from after the O2's were swapped.

Thank you.

[GHuggins]

As long as the valves are opening and closing correctly. There's no carbon much built up in the intake passages or on the intake valves. All rockers are torqued correctly. No pushrods tweaked. No obstructions in the intake manifold like a plastic divider or baffle broke. No vacuum leaks via smoke machine. No exhaust leaks. All intake boots correctly installed and not rolled. Rail pressure is staying around commanded. Then yes 99% chance it's injectors... Injectors are known to have issues and I've had a handful of customers with those issues. Seen them stick shut - usually noticeable on cold starts or wot, hang open - they'll do this whenever and cause a loss of rail pressure and I've seen them cause about 10% bank to bank fueling problems. One customer went through 2 sets before getting one with a 4ish % split he was looking for. The engine will run completely different with new injectors too. I don't think it'll fix your restart issue, but maybe some minor tweaks after the fact will take care of that.

[svl208]

So it's not uncommon for this engine to have injector issues?

Is there a way I caused this? Or is it the nature of this fuel injection system?

What could have caused this? How does this happen? I pulled both rails with injectors kept on the rails and installed with a new seals. They were never dropped or hit on the tips.

I gotta say I went over alot of the things you mentioned and I kinda think a bad injector is all that could be left as the problem.

My Gen 3 turd has never had an injector go bad.

Thank you.