greatmizzou

Totally forgot I posted this! I caved and took it to a dealer and it was a huge waste of time, they told me it was a battery issue.... anyway drove truck since then in December and no real problems until the no start happened again last weekend. Ordered official GM part and replaced it this weekend, truck starts great and no codes. looking into this, I dont think it requires any bi-directional input commands and just want to verify this. I did borrow my friends bi-directional scanner but it was out of updates so I couldnt check anyway for any type or calibration/relearn code. on a scale of 0-100, how necessary is it really for me to perform this process if it is functioning?

That is promising thanks! I have a friend with a bi-directional scanner where this might work out.

2020 3500HD 6.6 gas with about 69,000 mi. I had a crank no start a month ago and then just recently truck had trouble starting and would die on the road. Code P129F and my best guess is I have the fuel pump control module failure. GM only recalled certain vehicles so I guess mine is on me for now. Internet advice tells me these have to be reprogrammed at the dealer. Some people report they have swapped it and it runs fine. Whats the official verdict? Can I replace this myself or am I stuck using the dealer? It looks like its relatively easy to replace.

Just read the NHTSA media release about 6.2 engine failures for L87 2019-2024 Reminded me of this thread!

Anyone have a source to reflect changes of this model over the years? I have a very early model run from 2019, pre Covid. One of the first changes I noticed was that my LT had button door locks on all four doors. Newer ones are or were just on the front two. I then saw a newer 2500HD 6.6 Diesel in the parking lot and noticed the rear wheel wells looked significantly more bare. I know I have an extra leaf spring on my 3500...but it looked very different. The frame was well exposed and mine is not. There was an anecdote that manufacturing quality during and immediately after Covid took a nose dive and that is for all industries. Has anyone else experienced that with this Model run? I plan on upgrading to the 10speed transmission eventually, but to be honest my truck has been so solid, sometimes I know its better to keep a well built vehicle then potentially get a problem child if its not of much improvement. 2020 3500HD LT 4x4 Crew cab 6.6 gas

My 2020 wax frame is still doing well. I have driven it very limited though when road salt is spread. my 2002 1500 was abused and rarely washed underneath...the frame only had surface rust and some wax areas were still there. The cab corners and rockers were another story :(. the part that really rusted out was the rear axle. my wifes 2006 Honda civic frame looked pristine up until 2016 when we sold it. Thats Midwest salt roads and all. Her 2015 CRV and later 2020 CRV were also pristine. Whatever Honda does (or used to do) to keep their frames so nice I wish was emulated by GM. However, I did see a few gently used newer model hondas that came from Michigan that looked pretty bad. Probably never had an undercarriage wash

This puts me at ease more, definitely going to be more careful moving on

I think it was one of my bath towels I used, ive never had a problem before but the paint coat on this 2020 just feels different then the paint on my gmt800. That truck felt "harder" and had a nicer paint coat.

I noticed yesterday my paint has swirlies all over. I washed and waxed it today with the OG turtlewax and it still holds a nice shine. If im not terribly concerned about swirlies and make sure Im not using old towels to dry the truck off again, is there even really any concern if I keep it clean and waxed?

I checked the website and it shows the gas l8t will now be paired with 10 speed Allison FINALLY. i imagine its a step option but perhaps all HD trucks will have a 10speed allison now?

Per the haynes manual you can check a fuel sending unit with an ohmmeter when you remove it. Watch the voltage change by physically moving the fuel float. If its not smoothly changing then your sending unit is bad. If it does report smooth changing voltage, then the problem is further up the connection to the dash. The dash itself has a lot going on that might not be reflecting the incoming data appropriately. Does everything else otherwise function appropriately, like does it start and run or change fuel level as you drive? It is possible the problem had nothing to do with your sending unit in the first place. Test the other connections in the circuit and look for bad/open grounds, bad wires, blown fuses, etc

You said the process stopped with conditions not met. If your friend gm tech can check the service manual, see if he can find what conditions are required. it might be something as simple as your engine temp is too cold.

For someone who said they never worked on their own truck you said a bunch of tech lingo way over my head! Isnt your 5.7 a vortec?? As far as I know you cant adjust timing on those 1996-2000 obd2 engines. You might not be able to do a crank relearn with your scanner. You can however troubleshoot the crank position sensor and make sure its got the right voltage with a voltmeter. P0300 is a cylinder misfire code I think. Double check you replaced the distributor correctly and put the plugs in the right spots. "On SFI V8 engines the timing cannot be adjusted; however, if the distributor has been removed, it may need to be turned slightly in order to prevent cross-fire (cross-fire occurs when the ignition fires while the rotor is between two terminals on the distributor cap). A scan tool is necessary to test for cross-fire, so this operation must be performed by a dealer or qualified repair shop. "

Well found my other engine problem. Huge exhaust leak was obvious but still threw p0102 etc MAF codes. started cleaning my grounds along the harness then followed one strand to rear engine block and this ground was disconnected. Cleaned off the engine block bolt and reconnected, runs pretty good and no codes so far! glad I replaced the exhaust anyway because I noticed heat was starting to mess with the wiring harnesses Now on to the wheels, pretty much everything is going to have to go and dreading getting the control arm bushings replaced. On my gmt800 I just bought new control arms but Im trying to save money on this one.

Took off the exhaust donut gaskets because they were toast. Huge leak coming from there. Broke off one of the manifold bolts, no biggie. Took both manifolds off to replace the studs and both manifolds had cracks in the center. Not the end of the world, they looked roasted anyway. Got the replacements in and hopefully gets the engine somewhat back to normal!