Everything posted by Jsdirt
The stuff to use is BG44K for a commercial duty fuel system cleaner. They may have a newer formula for direct injected engines, but I haven't had to search for one, yet. As you might remember, I've had nothing but issues with my '07, right from the test drive! Had 42 miles on the clock, and the brakes would just about give you whiplash with severe pulsation. Driver's side door trim fell off the 1st week I had it. Interior developed more interior squeaks and rattles at 2k miles than my 266k mile K1500 had. Lower ball joints didn't even reach 40k miles, engine started burning oil & front axles leaked at 50k, followed by upper ball joint failure along with one strut, then the 4x4 switch failed & hub bearings failed all before 75k, rear diff failed at 97k, transmission at 103k, and now the engine has low oil pressure getting lower with each trip at 117k. Been a lemon of lemons, lol. Yeah there's quite a few shops that fire the parts cannon, too. Have to go by word-of-mouth, or read MANY reviews when picking a shop. Some are full of super sharp guys that thrive on drivability and electrical problems, and will get you out the door quickly for reasonable cash. Others aren't much different than dealers in that they'll fire the parts bazooka at the truck, empty your wallet, and never fix the problem after it sits in their shop 4 weeks or more. Really have to do your homework. I get a TON of customers frustrated with other shops and dealers doing this exact thing. If you want to learn engine and electrical troubleshooting, Paul Danner is the man. He's got a website and YouTube channel - scannerdanner.com, and ScannerDanner. He's got a Premium Channel on his website that costs $11 a month - best bang for your buck in the automotive world, hands down, full stop. I've been subbed there for 5 years now, and it's enabled me to take on hundreds of jobs I would've refused in the past. He's really sharp with this stuff. He also has a book out called Engine Performance Diagnostics that's very good to have around as a reference, too. If you have the time and are willing to learn, you can get to where you can diagnose anything on any brand without a wiring diagram just by watching his videos. He's got quite a few great ones for free on YouTube as well. His brother James owns a shop in PA, and he'll frequently film all the problem children vehicles that roll in there.
Yep you're on track with that - the post cat sensor could be telling the truth. Might have a clogged injector, or more on that bank. Usually the fuel trims will be in the double-digits positive in that case. I would suggest ANY shop over the dealer. The pay scale doesn't encourage a good diagnostic approach to issues like this. The more complex the issue, the more trips back you'll go for them to fix their misdiagnosis. And when they start winging parts, YOU pay for ALL of it. You could leave there $1,500 poorer, and have the same issue. Go to ANYONE but a dealer. Is that direct-injected? I hear those are having a ton of issues over the model years, the least of which is the valve coking problem caused by the direct injection.
I'd be steering clear of any dealership with an '18 anyway. Your warranty is long gone now. I'd be doing a compression test. Sounds like you've got some internal engine damage from here. 3rd and 4th gear are higher speeds, more wind resistance, so, more load. Sounds to me like the engine can't handle higher loads. More than likely some valve train issues, but could also be lower end issues as well. All depends on the frequency of the "tick". These trucks are so hit-and-miss with quality anything is possible.
It does NOT lock the ECU / PCM. It locks the tool so you can't upload it to more than one vehicle. It also captures your stock info in the tool, which cannot be uploaded to any vehicle but the original. With a J-box you can wipe the PCM and start over. Look at the link I posted to the picture straight from the manual - "If a service facility reprograms your vehicle's computer with an update, your Hypertech Power Tuning will be erased."
AMEN to that! If I had my way, I wouldn't drive anything built after 1972! We've got a '86 Grand Marquis daily driver that's all stock and original. Still runs the original OE in-tank fuel pump - 36 years, 285k miles! Try that on anything built in the last 25 years. We take it off the road every winter, otherwise it would've rotted away to nothing 25 years ago. The road salt up here is brutal. We run a '93 Volvo 940 for a winter beater. They used top quality metals and paint on this thing - been in New England winters since it rolled off the showroom floor in '92, and has minimal rust and no rot. Slow as slow can get, but it's as reliable as a stone ax, totally unlike my Silverado has been. I'm at 117k on the Silverado, and I'm planning an engine swap already due to low oil pressure. Started burning oil at 50k miles! Had nothing but trouble with this thing since DAY 1. Brakes, ball joints, rear end failure at 97k, trans at 103k - one thing after another.
I've got the Hypertech tuner on mine - bought it in '07 when my truck was still brand new. Got a cold air intake, and Corsa cat back system, and that's it as far as mods go. It woke the truck up pretty good. I have all the transmission parameters set to stock, since my transmission is built to the moon, so all of that has been taken care of by the builder. I can actually break stuff inside the trans if I go ramping up shift firmness, since my pump is already set to run in triple-digit pressures. Back when the truck had the original trans (before 103k miles), I cranked up the shift firmness as high as it would go. That probably got me several thousand more miles out of it. Yours is built MUCH better than mine, so you won't have to worry about that too much. From '07-up, parts quality of these trucks really took a nosedive. As far as shift RPM and rev limits, I left all that alone, since there was no reason to increase or decrease any of that from stock. One time I screwed up and changed the rear end gearing in the tuner - thought I had set it back to where it should have been, but I missed a key step. Every light on the cluster lit up, shift points were screwed up, and the truck was bucking and surging like crazy! Luckily I didn't break anything. The shifts were violent. I only drove it 4 miles that way.
Rev limits and shift points are adjustable in the tuner. Someone jacked it way up to the moon, and probably didn't understand what was happening when it hit the rev limiter, and dumped the truck. I hate when people do that and don't include the tuner! Pretty much screwed without it.
Without that programmer, the only thing you can do is have the ECU wiped and reprogrammed at a shop or mobile programmer that has a J-box. It's costs to get the required info from GM's website, plus the persons time, so you'll be into it for at least $200 I figure. Might be cheaper in AZ. Either that or grab another one out of the boneyard (which might require programming anyway to get certain options to work), or, find one of those guys on eBay that'll sell you a used ECU, and they'll program your VIN and options into it prior to shipping it out. What exactly was done wrong? Wrong axle ratio? That's about the only thing that'll screw up drivability with a Hypertech. Those things are so easy to use, a 4 year old could do it.
A few things could. Failing fuel pump, throttle body, or wiring issues. Also stale gasoline, or gas contaminated with water, fouled plugs, or debris in the fuel system, and probably 20 other things I'm not thinking of. Have to get a scan tool on there and see what's happening when it stumbles.
Yeah, that's usually a dead giveaway to look over your work and check the fuses, too.
Good deal - I didn't see the other half of your post about the codes until just now, but glad you found that issue. I always tell people that multiple codes are usually from a lost power or ground, since that's true 9 times out of 10 as you've just found.
I'll be doing this job on my truck soon. 117k miles. Oil pressure started trending very low compared to usual a few thousand miles back, and has been trending lower pretty quickly. I've owned mine since day 1, and run nothing but the best oils available once broken in. I suspect my issue is the #2 cam bearing walkout based on the amount of metal in my oil analysis, but going to replace the pickup tube o-ring since it's such a common failure point. Going to check the screen just in case, too, even though I probably have the cleanest engine out there. I'll be installing one of these to keep that o-ring issue from happening again: https://www.ictbillet.com/ls-billet-oil-pump-pickup-girdle-tube-pipe-hold-down-brace-support-ls1-ls3-ls2.html I'll also be shimming the oil pump pressure spring, and might give the one in the pan a whack or 2 as a preemptive strike to keep pressure a bit higher than normal. While everything is apart, I'll throw in the shield that's in the oil burning TSB if it doesn't already have one (doubtful the dealer installed this). Anything to keep this engine going. What a friggin PITA, though. NOT what I expected when I bought this thing brand new 15 years ago ...
These things have notoriously crappy wiring and grounds. Start with those first. These trucks can frustrate the crap out of you, leading you down the rabbit hole. Engineers today need a severe beating by every tech that's wasted half his life troubleshooting these turds. Could very well be the BCM, but check the basics first.
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