287,500 Mile Service
8/13/2026
Reset Fuel Trims
Since the work done in the previous post there was a good improvement in response in all areas except right after a fill up where the LTFT would go -20%+ for about four miles while the STFT was near neutral. Before the work they both went very negative for a few miles after a fill up but act normal thereafter.
We did a systems check of the vapor recovery system for functionality and ability to hold a vacuum. That checked out fine. But this doesn't mean the charcoal canister is dead in the water. Testing that is next up. For now the reset of the fuel trims.
I intentionally shorted the fill exactly two gallons to eliminate any chance of filling the canister. On start up the trims were behaving normally until I got up and rolling where the LTFT went -10 / -11%% but the short was + 2 to 0%. Within a mile the the STFT offset the LTFT and by 2 miles they were neutral. HUGE improvement but still not hunky-dory.
I'll watch them for a few days. Perhaps another tank where I will fill completely to 'first click' and compare. Meanwhile on the hunt for a new canister and I'll toss another purge value at it for good measure. Pending the outcome of the canister test that is. Progress of any kind is welcome.
Fuel economy improvement with bringing hole #3 back to the living was a noticeable bump to the positive. Even on the few miles I drove after the refill I already see another bump up by the trims reset.
She's purring like a kitten with a warm bowl of milk.
Yeah, shame I can’t really get that filter easily anymore. Running a PureOne. Your fave!
TAN would be neat to see. Confirmation I ran it too long probably. 🤣
My son and I both bought new trucks in 2017. Both of us immediately put Truck Covers USA American Roll Covers on our trucks. My son still has his truck and it never sees the inside of a garage. We live in Alabama, so not much snow. My truck was my daily driver and was in the garage when I wasn't driving it or at work. No issues with either cover even after almost 9 years. About a year ago I sold my truck to my brother and bought a 2025 Silverado 2500. The second thing that I put on that truck was a new Truck Covers USA cover. They are very well made and have a very positive locking system. I looked at a Retrax and my concern was the way that the cover locked to the rail. BTW, the first thing I put on the new truck was step bars. Those new trucks are high!
The Allison 10 speed torque converter doesn't "lock up" like the previous transmissions. It has 4 operational modes; open, slip, transition from open to slip; transition from slip to open. I have an Edge CTS3 monitor and I monitor transmission torque converter slip. Step on the gas and you get a little slip. Take your foot off the gas and you get a little negative slip. I have not found a way to display the torque converter mode beyond that. My Edge CTS3 also displays something that our trucks should already display, the current gear. I also monitor throttle body position and engine load. If I see the engine load getting too high, I'll manually drop a gear.
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