Jump to content

6.0 pulling timing at 3000 RPM

Abarth500.
 Share

Recommended Posts

Abarth500. Enthusiast

Abarth500.

Posted
Posted (edited)

Hey yall! New member here, sorry for creating a thread so early on, but my warranty expiration is creeping up on me fast and I need to get this sorted- so here's my issue.

 

I have a 2015 2500HD with the 6.0 and about 95,000mi, and for the past 6 months, I've been having this issue where It'd start pulling timing ( up to 15 degrees of KR) under moderate to heavy throttle, as soon as it hits 3000RPM. There is no audible knock, but 15 degrees of KR sounds very excessive. Higher octane fuel makes the issue better,  and usually after long interstate drives (no heatsoak), it runs great, but generally, it's very bad. Towing a 32FT trailer full of band equipment up a mild hill, it struggles to get out of first gear, and slams into the next gear because the timing is so far retarded before the shift, that it screws with the shift timing.  I have used various fuel system cleaners ( now trying Amsoil Pi, as I know its well proven ) but so far, none have made any difference. I want to check the fuel pressure, but I don't see a test port, and I can't get any OBD app to display fuel pressure.

 

Here's what confuses me:  Sometimes, under the same conditions, It'll run just fine and pull hard straight through 3000 RPM. The only thing I can find different between the times that it runs like a POS and times that it runs like its brand new, is that when it's running like crap, it shudders at idle- enough to be felt throughout the entire truck.

 

It pulls the most timing at around 3000, and tapers down as the revs increase.

 

I got it used, with about 76,000mi, so I'm not clear about its past. Back when it was running horribly I was considering that It might have been tuned by the previous owner, but lately, its been randomly running just fine. 

Its been fine for the past week or so, but I'm still very curious about what could be going on. 

 

I have TorquePRO recordings of the issue happening, which I may upload later if that would be of any help. I've been hoping for a CEL but of course- no pending or stored codes!

 

Thank you all! Sorry for the length of the post!

Edited by Abarth500.
added a bit about the lack of CEL
  • 2 weeks later...
MNorby Enthusiast

MNorby

Posted
Posted

Have no input but in for updates. MAybe post on performancetrucks as you might get more tuner oriented folks there too. 

avalonandl Enthusiast

avalonandl

Posted
Posted

Tune it with a Diablo Sport. 

 

There is a schrader valve somewhere on the fuel rail.

Abarth500. Enthusiast

Abarth500.

Posted
  • Author
Posted
On 6/15/2018 at 3:52 AM, MNorby said:

Have no input but in for updates. MAybe post on performancetrucks as you might get more tuner oriented folks there too. 

Will do, thank you!

Abarth500. Enthusiast

Abarth500.

Posted
  • Author
Posted
8 hours ago, avalonandl said:

Tune it with a Diablo Sport. 

 

There is a schrader valve somewhere on the fuel rail.

I got a fuel pressure test kit, expecting to see a Schrader valve sitting on the rail and there wasn't one! Possibly it's further down near the tank since it's return less ans has a PWM controlled pump. I'll have to look again I guess.

  • 1 year later...
davester Senior Enthusiast

davester

Posted
Posted

Older 6.0's, from the GMT800's at least, the later ones had a returnless setup, and they had a Schrader valve in the passenger side fuel rail...

  • 5 months later...
Abarth500. Enthusiast

Abarth500.

Posted
  • Author
Posted

Wow. It's been a long time.  The primary driver of the truck drives it so calmly that the issue doesn't really bother him, and with me constantly running into dead ends I guess I just got discouraged and gave up on the issue...until now.

 

So here's where I am. It has the e78 PCM of course, and it seems a lot of local tuners don't really want to touch all of this torque based stuff, understandable, but it's stopped me from finding any local help. I've done some logs, but I wouldn't say they have been very helpful for me at least, and with few people wanting to look into it, it hasn't yielded much. 

 

The issue is very much still there, same behavior as before. Just thought i'd give an update since I left this thread dead in the water before.

 

Also fun fact, there is no schrader valve on the fuel rail for whatever reason. To test fuel pressure I had to hook up an adapter on the fuel line that teed into both the gauge and the rail. Weird. 

 

 

swathdiver Senior Enthusiast

swathdiver

Posted
Posted

Look into a VXDIAG NANO with GDS software so you can see everything and run proper tests.  Could be loose heat shield or something that knock sensors are picking up.  Good scan tool can read fuel pressure and commanded fuel pressure.  Maybe even your Torque Pro App if you get the right PIDs.  Ask Ken, KBUSKILL over at the TahoeYukon Forum.  Some guys here might know too.

  • Like 2
Abarth500. Enthusiast

Abarth500.

Posted
  • Author
Posted
On 6/12/2020 at 1:23 AM, swathdiver said:

Look into a VXDIAG NANO with GDS software so you can see everything and run proper tests.  Could be loose heat shield or something that knock sensors are picking up.  Good scan tool can read fuel pressure and commanded fuel pressure.  Maybe even your Torque Pro App if you get the right PIDs.  Ask Ken, KBUSKILL over at the TahoeYukon Forum.  Some guys here might know too.

Great, thank you for pointing me in the right direction. Looking into software, it seems you kind of have to go all or nothing with this platform if you want to do proper logging. It's a shame there aren't any $50 phone apps that can do it all, like I've found on other platforms. 

 

 

Looking into VXDIAG, also trying the software that came with my OBDLink MX. 

 

Any pointers on the specific parameters i should log to give data to the people trying to help out?

swathdiver Senior Enthusiast

swathdiver

Posted
Posted
11 hours ago, Abarth500. said:

Great, thank you for pointing me in the right direction. Looking into software, it seems you kind of have to go all or nothing with this platform if you want to do proper logging. It's a shame there aren't any $50 phone apps that can do it all, like I've found on other platforms. 

 

Looking into VXDIAG, also trying the software that came with my OBDLink MX. 

 

Any pointers on the specific parameters i should log to give data to the people trying to help out?

Well Torque Pro and there's another whose name I forget can see a lot of engine functions if you get the PIDs set up for them.  I would want to see the fuel pressure, actual and commanded, the O2 sensors and Long Term Fuel Trims, Spark Advance and all ****** options.

 

If yours were mine, I'd get the MDI2 with GDS2 software so I could see and test everything.

  • Like 1
Abarth500. Enthusiast

Abarth500.

Posted
  • Author
Posted

Well, after complaining about it I just sucked it up and purchased VCM Suite- it gets here Friday. I'll be sure to have some logs up by the end of the weekend.

 

I was looking into other options but as the price started to creep higher, I figured I may as well just get HPT and be done with it. Not backing down from fixing the issue this time :cheers:

 

Thanks for the help so far y'all, sorry it too me so long to suck it up and invest in something.

  • Like 1
swathdiver Senior Enthusiast

swathdiver

Posted
Posted
On 6/20/2020 at 6:28 PM, Abarth500. said:

Hi yall, here's a log, along with the config and tune.

 

I've been having a hard time getting the truck to act up like it has for the past 40,000mi (of course), so this isn't a great example of "hitting a wall" but still, lots of KR can be seen near the end of the log, with TPS steady. 

 

Thanks!

we did it 6.hpl 148.75 kB · 3 downloads Default 2.Channels.xml 1.97 kB · 3 downloads Original ECM TCM.hpt 1.82 MB · 4 downloads

Not able to view any of this, how about some screen shots?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • garagerog
      Low fuel pressure after installing new fuel pump

      By garagerog · Posted

      Replace the fuel pump with an OEM AC-Delco.
    • Gilkey96
      Low fuel pressure after installing new fuel pump

      By Gilkey96 · Posted

      Hello, first time posting here. I have an 03 Chevy 1500HD with the 6 liter gas engine. The truck ran fine until the fuel pump died on me and had to get it towed. Replaced the fuel pump with a precision pump from O’rileys and changed the fuel filter while I was there. The truck will run and drive now but it wants to idle around 500 rpm when in drive and it tries to stall if you touch the gas. It drives fine though, just doesn’t want to idle. Put a fuel pressure gauge on the rail and only have 50 psi. I guess these trucks should have 55-62 psi to run right. I thought the regulator might be the issue because when I would unplug the vacuum hose it jumped to 56 psi. Replaced the regulator and no change. The only thing I can think of is that I was sold a faulty fuel pump. Any help would be appreciated because I’d rather not have to take the bed off again if I don’t have too. Thank you!
    • diyer2
      AFM Experience

      By diyer2 · Posted

      I've been wrenching on GM trucks for 17 years. And I need to get something off my chest because it's been weighing on me for a long time. After all that time, all those motors, all those people standing in my bay, I've figured out there are really only two kinds of owners. The ones who already know about this. And the ones who are about to find out the hard way. A guy came into my shop a few weeks back in a 2018 Silverado 5.3. Sharp guy, maybe 35. Knew his truck cold. He'd been on the forums, read the threads, done his homework. He only rolled in so I could double-check a little module he'd already plugged in himself. Wanted a second set of eyes on it. Ten minutes, in and out, drove off happy. Two days later, a completely different story walked through the same door. Older fella this time, in a 2016 Sierra. Gorgeous truck, clearly babied, not a scratch on it. Wedding ring. Looked like a guy who took care of his stuff. He was in because his engine had started knocking on the way to work. And by the time I got the valve cover off, I already knew it was too late. Lifter collapsed. Cylinder 5. Camshaft chewed up. The whole top end shot. Same kind of truck. Same motor. Same roads, probably the same dealer. The only thing separating those two men was information. I've been at this since 2008, and I've worked on everything GM puts out. Silverados. Sierras. Tahoes. Yukons. Suburbans. Escalades. The 5.3 and the 6.2. Doesn't matter which badge is on the tailgate. They all carry the same problem. So here's the information one of those guys had and the other one didn't. It's called Active Fuel Management. AFM. GM started building it into their V6s and V8s back in 2007 to squeeze out a little better mileage on the highway. Maybe a mile or two a gallon. All to hit government fuel economy numbers. The way it works, the motor quietly shuts down half its cylinders when you're just cruising along. And the little lifters that pull that off have a tiny pin inside them that's constantly clicking in and out. Lock, unlock, lock, unlock. Hundreds of times a drive. Thousands of times a week. Eventually one of those pins wears through. The lifter drops. And it starts grinding the camshaft down like a chisel on butter. And what nobody tells you is that the shudder you feel around 40 or 50 mph? That's the system cycling. Every single time. Here's what really gets me. The pre-2007 trucks, the ones without AFM, they're bulletproof. I've got customers still daily driving them with 260,000 miles on the odometer. Not a problem in the world. GM took a perfectly good motor that would have lasted a lifetime and bolted this system onto it. And it is wrecking engines that should have run forever. The guys who hang around the forums already know all of this. So do the techs. They handled this years ago. They didn't sit around waiting for the dealership to mail them a warning letter, because that letter is never coming. It's the guys who figured somebody would've told them who end up on my lift. And I want to be clear, because this part matters. Maintenance has nothing to do with it. I've torn down motors with barely 30,000 miles on the clock. I pulled apart a Tahoe last summer with 24,000 on it. Practically a brand new truck. Owner had it less than a year. Spotless oil. Best synthetic money can buy, changed early every time. Made no difference. I've seen guys with full dealer records, every interval stamped. Made no difference. The oil changes were never the problem. The pin was. And no amount of babying that truck stops that pin from cycling every single time you drive. That's the part that eats at me. These are good motors. Take the AFM out of the equation and a 5.3 or a 6.2 will run 300,000 miles and never blink. So a few years ago I started telling every single owner who comes through my doors the exact same thing the smart guys already knew. Get yourself a FullForce disabler. It plugs right into the port under your dash. Couple of seconds and you're done. It just tells the computer to leave every cylinder running, full time. No more cycling. No more beating those lifters back and forth every time you turn the key. It doesn't reprogram anything. Doesn't touch your tune. And unplug it before a dealer visit and there's absolutely zero trace it was ever installed. I've had customers come back at 40,000, 60,000, 80,000 miles after I put one in. Zero issues. The trucks run smoother. And the lifters aren't getting beaten to death every single drive. I won't sit here and tell you it's magic. A lifter that's already damaged is a lifter that's already damaged, and this won't un-ring that bell. But it takes away the one thing causing all that wear in the first place. That's the whole game. You don't need a five-thousand-dollar delete. You don't need an expensive tune. You don't need to tear anything apart. You just need to stop the cycling. I'm not writing this for any company. I'm writing it because I'm tired of watching the guys who didn't know pay four and five figures for it. I'm tired of being the guy who has to break the news. I'm tired of knowing that the guys who did know fixed the whole thing for the price of a tank of gas, and the only difference was that somebody told them first. If you drive a Silverado, Sierra, Tahoe, Yukon, Suburban, or Escalade from 2007 or newer with a V6 or V8, you've got AFM. You've got those lifters, and they're cycling every single time you drive. So be the guy who already knew. Not the one I'm scraping metal out of next month. EDIT: A bunch of folks asked, so here it is. The one I put my faith in is FullForce. This is where to find it: https://www.tryfullforce.com/products/fullforce™-afm-dfm-disabler They back it with a 60-day guarantee too. I've handed out more than I can count and not one's ever come back to me. Not one. See less
    • Atlas
      Wow I'm in a pickle. (Broke down truck) and a story.

      By Atlas · Posted

      Thanks for following along. I'm not author material, my tenses are all over the place and an editor would have a heck of a time cleaning up after me. Reading and writing is still a fun pastime though.   My new scanner came in yesterday, wow, where the heck has this thing been?! It connects right up to the Blazer, there's all kinds of bidirectional tests like EGR activation and percentage, toggle the fuel pump relay, EVAP purge valve, IAC control, AC relay, reset the transmission's adaptive learning, toggle shift solenoids and TCC lockup, and I can reset fuel trims with the click of a button...all things I could have used over the last 60 days!   It's also telling me there is a stored code in the ABS module for front left wheel sensor open and something about the brake switch. The ABS dash light works. It illuminates normally during the self-test at key on/ start and that's it. I cleared the codes and will see if they set when I take it out later. That, and I'm going to get (hopefully) real data on timing and cam ******. The PID's are there.   I connected the tool to my truck...holy smokes. Newer vehicles make early OBDII vehicles look like 8-bit, pixelated, early Nintendo stuff. This? This is like wearing 3D virtual reality goggles playing one of those elaborate, cinematic video games with seasons and plots in comparison. There are SO MANY modules and SO MANY tests and SO MUCH data. There's a scanner sequence for filling the coolant...   End of the day, it's a tool with way more power than I need, but the versatility to do old and new is there (and I need an adapter to connect it to my OBDI Camaro). It will allow me to do the first pass of diagnosis when out-of-warranty vehicles need help, and it will enable more DIY maintenance like brake system bleeding, ABS bleed, etc. I probably over-bought here, but, mission is accomplished.   Enjoy your Sunday...I need to shut this machine down and go get ready for the week ahead.
    • MORSNO
      Which 2027 engine will you choose?

      By MORSNO · Posted

      Not that I've read, after all the issues they've had in the past I'm pretty sure they learned their lesson. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...