Hey everybody,

I made a thread in the new member section about my truck yet nothing about what I'm experiencing! To give an overview, It's a 2014 6.2 w/ 6l80. Bought it bone stock in 2016 and since then has been my 'toy.' It has a P1SC Procharger with the supplied 6 lb. pulley and was installed about 2 years ago. A few months went by after having just the Procharger on the truck - stock cam, stock everything else (aside from the lift/wheels/tires and tune) - and it bends a push rod on the #7 cylinder. Replaced and all was good - for the time being.... Then it happens again not even a month later. Same cylinder. Great. Changed it and ran good for a while. At this point, I went into full safe mode. Let's just do away with the stock cam/ pushrods, etc. Contacted Texas Speed, bought a cam package, DOD delete, and long tubes. Welllllll..... they sat for two years, up until 2 months ago when I finally decided to go ahead and get it all installed. Since purchasing everything from TSP, I blew through probably 5-6 more pushrods. Kept replacing them just to keep the truck semi-driveable. Same cylinder, every time. I got fed up and decided it was time to get it done. Anyway, to make a long story short, the cause for the bent pushrod was because the lifter was bent! Cool, well, TSP provided some GM LS7 lifters to replace them so no worries there. Truck is done, cam/dod delete, headers done, runs and drives like a champ, everything is good.

Fast forward to this past week...

I noticed after doing a pull or two from about 30mph or so that I see my oil pressure drops... to 0. Then jumps back up to 40 after a few seconds. This does not happen every time. I assumed maybe just the oil pressure switch. No light came on, no indication, it just did it and came back like nothing happened. Decided to get a second opinion from a friend of mine who is very knowledgeable on LS stuff. Take the truck for a ride, do a few pulls to see if we could duplicate the problem... nothing. We get to a back road after running it one good time, and a CEL comes on. He plugs in my handy dandy little $20 Walmart scanner to see what is possibly going wrong. They were codes I have seen before on a few occasions before the cam install - P2230 barometric pressure sensor erratic and a P0121 TPS Sensor code. We clear it on the fly. Upon passing by our local Walmart we noticed the truck developed a skip or a misfire after doing another small pull. All we could do at that point was wonder what happened? No code appeared, no CEL, nothing... It sounded mostly like a top end issue, consistent for sure from idle to WOT but certainly not a lower end knock/etc. We decided to call it a night and try again the next day as I was in town for work this past week. I get off of work early, decide to pull a plug or two to see if they may have fouled out, nothing. Had my friend come back over with his fancy Snap On Zeus scanner to see if it could detect the skip/misfire I was experiencing.... Still nothing..... Checked the injectors via scanner... nothing seemed out of place. It just didn't want to show it's face.

If you've made it this far, you're a trooper... At this point I began to worry a bit. My friend decided it was best to bring it to his shop and we do a compression test. I take the truck to his shop, I pull all of the plugs, checked all of the wires, everything appeared okay. I noticed a plug wasn't tight on the #6 cylinder thinking that might've been the culprit but I went ahead and did a test on each cylinder just to be safe. All read close to 215psi thankfully. Put all the plugs back in expecting everything to be okay now, 'it was the loose spark plug' was what I kept thinking. Well I was wrong. Skip/misfire is still present, no better, no worse. At this point, we're kind of stumped. Not sure where to go, what to look for or anything. I keep wondering if it's tune related because I keep getting a strong odor of fresh 93 at idle. Could be running rich, but no way of telling because I don't have a wideband yet. I'm also am not ruling out something mechanically went wrong. Like a bad injector, bad coil pack or even a chipped valve or something. I would think that something like that would show itself on the scanner.... but it's not. So I wanted to reach out to anyone who maybe had any suggestions or have experienced any of this before we embark on another tear down to find out what's going wrong.

I do apologize for the seemingly long post, but I felt this was kind of an odd case. I know there is no way to really know for sure without tearing it down again but I figure before spending money on what 'could be' the problem, I'd just ask.

Thanks for reading and I look forward to seeing some of your responses!

 

You didn't mention if the truck was tuned after the cam/headers install. With a performance cam the tuner disables a lot of the DTC's (Diagnostic Trouble Codes) because the sensors will misread the extra duration (lope) as a misfire. Did you replace the spark plugs to eliminate the chance of a bad plug? If you have a burnt or broken valve it will show up during a compression and or leak down test. BTW what are the cam specs? The rich smell during idle is pretty common due to the (some cams) cams larger overlap where the exhaust contaminates the intake charge at low speed/idle... not saying you're not experiencing a rich mixture along with the exhaust smell. With your forced induction setup a wideband is a must have.

 

Hi RedXray,

The truck was tuned on the street using HPtuners from a friend of a friend after the cam and headers were installed. I was traveling for work at the time it was being tuned so I didn't get much info on what was changed from the tune with just the procharger and what wasn't changed. The only thing that was said to me that was comforting to know was that the air/fuel was good from idle to WOT and that it ran better than it ever did. I'm sorry if it's not any more informative, that's about all I got out of it. We have him on speed dial but he can be difficult to get ahold of him at times. Let alone getting him to come back to drive and make any changes to the tune. Took him almost two weeks to get out to tune the truck after everything was done! Nothing against him, he's just a busy guy.

Plugs and wires were replaced after finishing the cam. Not after doing the compression test though. I just inspected and what appeared to look good I put back in.None of them looked like they were fouled, cracked or different than any the others May not have been the best idea but I'm running NGK TR7's and they aren't cheap nor are they readily available in our area.I suppose I could order a few more online just to have on hand. I wanted to do a leak down test today as well but it was getting late so I decided to call it quits.

It's a 223/227, 116 lsa cam with the 32% fuel lobe. I do recall after the procharger was installed that I could smell unburnt fuel before the cam and everything else was done. But this is just going strictly off of the scent of fuel. Nothing else. So I could certainly be wrong on my assumption. As far as the wideband, it was on the grocery list, still is. I bought an Edge Insight second hand from my old boss a while ago and tried to get it to work, but the dang thing doesn't even turn on. Realized it wasn't worth trying to get the Insight to work, a lot more involved to try and get it to work, more pieces I have to buy, yada yada yada. My plan at this point is to get just some old school gauges and mount them on the pillar. I'd feel better about reading an actual needle anyway instead of relying the digital stuff and hoping that it's right. Probably gonna do a catch can too. It sounds shady that I'm missing some pieces to the puzzle here, but this my first vehicle I've ever owned where I decided to cam, turbo or supercharge. I've been around turbo/supercharged cars through my friends since before I was able to drive, just never owned one and understood what all was necessary until I decided to jump in 2 years ago. I guess I can say I'm still somewhat of a newbie to the cam and forced induction gangs. The truck also was put on the back burner because I needed a daily so some things kinda slipped through the cracks. Then I bought another daily because my first daily needed some extensive work as well haha. Needed some sort of reliable transportation and this truck along with my first daily wasn't cutting it lol. Thank you again for responding, if you have any more questions, feel free to ask me and I'll do my best to answer them.

Have a nice night, take care!

 

I understand your tuner woes for sure. My local guy always has a three to four month backlog, instead of waiting I bought HP Tuners and learned how to tune my truck. My 2000 GMC is much simpler to tune than your 2014. I'm not saying at all that your tune is not spot on perfect but a wideband install would be good to verify the air/fuel plus it's like a safety net in case any issue arises. If you ever decide to jump into tuning yourself Kyle from "Goat Rope Garage" is the guy to follow on youtube. He has a 2015 Procharged Silverado and he loves teaching new tuners how to tune their vehicles. Watching his tuning tutorials was the key for me understanding enough to successfully tune my GEN 3 platform.

He also has a Pateron where he reviews your tune files looking for issues and making any change recommendations by e-mail. Thursdays from 8:00PM to 9 he has a live Youtube session where he answers tuning questions and about 80 or so people chat about general GM vehicles. it's informative and pretty fun BS'n with other car guys.

Pateron Goat Rope Garage

Goat Rope Garage Youtube Channel

Go to Youtube to see the live chat!

 

Thank you for your swift and informative response! I'll have to go give him a watch. I'd like to get into tuning, I think it would be neat to dive into it and kinda learn the in's and out's. Once I know for sure that I have a solid tune on the truck, I'll save it and give it a go. I feel I'd get cold feet because this is the newest vehicle (also the most expensive vehicle) I've ever owned, so I wanted to leave it to someone who knew what they were doing. But it's not getting any younger and neither am I so I think it would be helpful for me to know and understand what all goes into tuning it without doing severe damage. I also have a junkyard gen IV 5.3 I'd eventually like to drop in my little Ranger once the motor goes in her. I think that would be a great candidate for learning how to build and tune without having all the risks. But I keep telling myself "one project at a time" haha so I need to finish this truck first..

I also just noticed you're from Lake Wylie! I'm out of Columbia! If you ever find yourself in my neck of the woods, give me a shout!

Thanks again for dropping some good info!

Griff

 

I've seen this before but it was a collapsed spring. What plugs are you using?

 

Thanks for dropping in smokinlmm,
I’m running NGK TR7IX plugs. They were recommended to me by TSP given the specs of the cam and supercharger. I’d imagine plugs aren’t the problem but I could be wrong. I honestly didn’t gap them or even check the gaps. But there’s gotta be a deeper root to the cause. This is a major power robbing issue. Not just a slight misfire.

It occurred to me after reading the post about the tuning issue and that DTC’s could be disabled for misfires due to the cam is getting my hands on another coil pack. Take one off and swap it with the new one. Fire the truck up and see what it does until I find the one that could potentially be of fault. If it doesn’t work then I know I can rule out a coil pack being the culprit. But sheesh, $100 for not even an AC Delco pack is kinda steep for just a hunch.

 

Here’s a small update,

So I visited my local O’Reilly’s to pick up a single coil pack... brought it home and immediately started swapping coils. I started with bank 2 and went down the line 2-8. When I got to the #8 cylinder it seemed to idle better. So I unplugged the new one to get the old one out and bolt the new coil pack in it’s place to take it for a drive. Upon starting it up again and taking it to the end of my street it was misfiring again. I guess it tricked me because all I was doing in the driveway was letting it idle and rev it to about 1500 rpm to see if there was a difference. So I backed the truck up into my driveway and went to the driver side.

Same misfire continued for cylinders #1 and #3. Losing hope and patience, I get to cylinder #5, the clips that are on the plug from the harness to the coil packs were sort of difficult to get off and were kicking my butt for some reason. I ended up breaking a tiny piece at the end of the plug where it goes into the coil pack.

Noticing this I began to get angry, but I plugged it up, praying that my efforts weren’t going to go to waste. To add to the frustration, as I hop down from the engine bay to go start the truck, I ripped my pants!!! Complete spongebob moment. How could it get any worse right??? Get in the truck, start it up, had sort of a hard start, began to start thinking it’s gonna be the last #7 cylinder or that it’s not a coil pack at all. Once running, it seemed to idle a lot smoother so I bolted it in and took it for a drive.

From the get go, it seemed a lot better than what it was. I was able to get to WOT and test it a bit. I can’t really tell but I feel there’s still a slight hint of a small misfire. I may just go with it for now and see what my friend thinks.

*Edit* - While the truck runs way better than it did on Friday, there is definitely another misfire. I'd assume it's another coil pack going bad. The truck certainly doesn't run bad, I don't know if there was just a combination of packs going bad but I feel my best bet is to just go ahead and do them all for reassurance. I can get a good deal on some MSD coils. I also see the Granatelli coils as well and they seem to yield pretty nice results. I may give the MSD coils a try and see if they clear up this issue. I'll check back once it's all said and done, let me know what ya'll think!

Thanks in advance!

 

Do you have a scanner that lets you see live data for the misfire or is it setting codes for those cylinder misfires?

 

A friend of mine hooked up his snap on Zeus scanner the night after it happened. It didn’t show any misfires for any cylinder at idle. Literally 0. We even took the truck for a drive to see if there were any changes but still nothing.

I think redxray was on to something though as far as disabling dtc’s for misfires for the cam via the tune. Since they were disabled (verified yesterday by the guy who tuned the truck) maybe the scanner wouldn’t be able to detect them at all because of this.

I also watched a video on YouTube this week of a guy who plugged up a scanner to like a 4Runner that had an obvious misfire yet the scanner said it was running just fine, no misfires. It was something along the lines of using some paper clips and pulling the coils while the truck was idling/ under load (Something I wouldn’t do and didn’t try but it worked for him.) He changed the coil pack and the truck ran smooth as silk. If I find the video I’ll drop a link.

Now I feel more confident that it is a spark issue because of the changes made by one coil pack leads me to believe it is just the coil packs. I guess there are only 4 things it could be.

1. Spark - New plugs and wires already installed but still running the O.E coil packs that have never changed.

2. Fuel - bad/dirty injector, bad gas, fuel pump(s) dying, etc.

3. Air/Vacuum - undetected leak somewhere, evap

4. Something came apart in the top end like what was said above - broken valve spring, rocker, pushrod etc. (but I think this would be much more noticeable - a bent pushrod almost sounded like a knock - and wouldn’t have changed the symptoms like when I changed the coil pack)

I also did a compression test to see if it could be something in the bottom end. Nothing out of the ordinary and came back with good compression across the board. So, for now, that’s ruled out.

I’m 75% sure that it is another coil pack. If replacing them all doesn’t work, at least I can rule out number one (for the most part) and I won’t have to worry about it for a while. Going in blindly definitely didn’t help either but I think I have a decent game plan given the circumstances.

I’m gonna order a set this week and change them out when I get back into town from work.

Thanks for reading!