Its been a while since i scanned it but i had filter set so to capture only multiple knock events. At the same time I could see timing being pulled. I applied a correction based on the scan to the timing and timing stabilized. From an engineering perspective I appreciate the ability for the ECU to control advance/KR to ride on the bleeding edge. I figured the 91 Oct was on low side for an engine tuned for 93 Oct thus more knock on the high octane timing map. I pulled up a scan you can see the timing droop down when throttle went up ~1% and some knocking. I was scanning on a trip and afterward i believe i had injector problems and had to take it in for second time. Haven't had any injector problems since clipping out the KR.
I don't have a BBP tune but was scanning 17 6.2 with HPT and could see i was getting some kr just driving highway as road goes up slight elevations. The highest oct i can find here is 91 so i modded the timing map slightly where it was occurring and the truck seems to run better with 0 kr now. I don't have any hard proof but i don't think constant background knock is good for gdi injectors. Saving a few cents on gas may not be worth it.
IMO the stock springs will ride OK. I just did the 1.75" drop shackles and billsteins and truck is level. It rides a bit rough on rough roads but glides well on decent roads ...better than the stockers. I Added airbags for when when i pull the trailer too keep things level.
I somewhat disagree with the Weight dist hitch crowd. That device is NOT supposed to help SUPPORT the LOAD! its job is to virtually shift the load from the rear bumper to just forward of the rear axle (Like a fifth wheel). If you add too much WDH it is possible the load point can be too far forward. In this condition if you have a hard braking event the front end will dive and the rear wheels will lift/unload and jackknife the rig. Carrying a load is the singular job of springs and air bags. either get beefier springs if you tow a lot or a good set of airbags to keep good ride when not towing. I use airbags and pump them till the truck is level and then set the WDH taught enough that the rear stays planted well not lifting and front doesn't dive under braking. Adding high pressure tires and friction sway bars are also great ideas. I pull a 32' toy hauler right at the max of the max tow pkg in a 1500 6.2 truck with some scary moments till I sorted this out. now it is solid and predictable. Do Not Over tighten the WDH it is dangerous!
I let mine go down to a few pounds and with bilsteins in the back the ride is great. If pumped up to 10+ it rides rough for sure. The bags are not replacing any spring ...they are in addition to springs. add air when you need more spring like towing. I just add enough air to get back to same ride height when towing.
There is a transmission thermostat that bypasses the cooler. It can be disabled/bypassed by flipping over the internals. This will drop temp at least 30 degrees and can be done in 20 mins under the truck. no need to replace anything and dealer uses M1 LV fluid in the trans already afaik. Do a search for the trans tstat mod.
Ive had my 17 with 50k miles in two times for injectors. The comments Ive read all you can do is run seafoam or injector cleaner thru at regular intervals or oil change time. While it is direct injector so wont help valves. The notion is that it may help the injectors to stay clean and keep them from leaking or sticking. From that video the job looks doable by a competent wrench.
Speedo correction wont make more mpg. It will read correctly on dash and I believe my trans TC shudder issues cleared up after correcting using hptuners. Rear is actually lowered and front raised - leveled with bilstein shocks. I have Michelin defenders LT275/65R20 crammed into the wheel wells which are ~10% larger than stock and 53 lbs each. There are several ways to get the speedo corrected either diy or take it to get tuned by someone reputable. If you do a lot of stop and go traffic a lower gear ratio may help your mileage a bit also. tall heavy tires on tall gear you must use a lot more gas pedal to get things moving.
First thing you need to do is quantify the speedometer error from the tall tires. That error will also be the MPG error so it is nice to know. so for a 10% speedo error your actual mpg would be 12 + 10%,1.2 = 13.2mpg Use a GPS or the Waze app on your phone to get the true speed on highway and note the dash speed difference. I believe that correcting the speedo differential will also help the trans some dealing with the larger heavier tires. The trans functions on torque loads and rotational speeds to calculate all sorts of things. I have the same truck with max tow and get in 13's pulling 10k trailer at moderate speed with large diameter road tires.
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