Project Update for June 5, 2015: Wow, been a few months and we've finally gotten around to some updates to Truck Norris. A nagging "CEL" has been repaired, the truck was custom dyno tuned (which fixed a bunch of issues), we got yet another new windshield (freagin rocks!), and some busted lights were replaced. Let's cover it...
CUSTOM DYNO TUNE AT TRUE STREET
So Truck Norris has been running progressively worse for months, and we've had a Check Engine Light since we put the headers and new exhaust on. I know why, and we knew it would happen, but I figured I'd get the truck custom tuned at some point to work with the mods that it has (cold air + full length headers). The state inspection finally ran out, and I had to get it tuned before it would pass again, so I finally called the folks at True Street Motorsports and got an appointment to bring it in a couple of weeks ago. These are the guys that have tuned our 2011 Mustang GT so well, and we send all manner of cars and trucks their way for EFI tuning.

As I try to do when getting work done by any outside shop I made them a list of the mods we knew the truck had, the problems we were experiencing, how we used the truck, and sent a copy via email when we scheduled the work + left a printed copy on the front seat to make sure they knew what we had and needed. I asked them to fix the CEL, dyno tune the engine/air/fuel/spark, up the line pressure in the automatic trans (it was slipping a bit), see why it had crappy fuel mileage, calibrate the speedo for these 20" tires, and see if they could tame the cold start hunting idle. They also knew to tune for cheaper 87 octane fuel, daily driving and hauling around heavy loads from time to time. I wasn't looking for a race tune, just a good safe street tune. The current state of tune on the motor was a total mess... but they did their magic!

As you can see from the dyno sheet above there were some issues with the (before) stock tune when coupled with the K&N cold air and ARH headers, plus our custom exhaust. A previous owner had installed a different set of headers (craptastic and leaking Edlebrock shorties), a janky exhaust, and the K&N cold air... tens if not hundreds of thousands of miles ago. After so many years of abuse the actual air filter element was old, dirty and had a big hole in it (which I hadn't seen - doh!). They called before they replaced the filter, which I thanked them for finding, then did a base line pull. They said the fuel trims were off by 25%, with the engine running lean and the computer trying like mad to get it all sorted via the O2 readings.

I daily drive this truck from home to work, then it gets used in deliveries, and our mixed but consistent city/highway fuel mileage had been steadily dropping from around 14-15 mph to 11-12 mpg of late (I log every fuel fill up and calculate the mileage over each tank), so I knew something was wrong - even considering the speedo was off by about 8% due to our tire height change from stock. After the custom dyno tune the engine picked up 13 whp at the peak, but more importantly it RUNS 100 times better. I've been driving it for about 2 weeks and it is an entirely different experience.

Sure, it only makes 260 whp and 300 ft-lbs at the tires, but its literally the weakest 5.3L engine GM ever made and was only rated at 285hp at the crank, stock. It also has racked up over 245,000 miles. I'm just happy that it still runs, holds most of its fluids inside the engine, and gets me to work every day without fail. After the re-tune it feels a lot crisper on throttle, the transmission isn't slipping, and the idle speed is rock solid, hot or cold.

They only had the truck in for tuning for a day, and the fuel level was low after they were done, so I filled up the tank on the way back from True Street. After driving all over town for about a week and a half, it had gone through 19.55 gallons of 87 octane. With the speedo now calibrated (which hurt our numbers) the truck still managed 15.65 mpg on that tank, compared to 12.73 mpg on the previous tank (and the trend of 11-12 mpg had gone back for months in my fuel log). Lots of people drove the GMC over that week, including me, Brandon, Brad, Shannon, and one of our customers Marc - who all had driven it before, and each remarked at how much better it ran and drove. Good stuff.
NEW WINDSHIELD - NUMBER 3!
Over the time we've had this truck it has had a few rocks fly up at the windshield. It gets driven around Dallas and Ft. Worth to pick up and drop off parts from our various machine shops, platers/coaters, and other vendors. Often times it is driven in heavy traffic, through construction zones, you name it. I bought this truck with a giant crack in the windshield, which I had the folks at Titan Auto Glass replace last year. It was nice having a new windshield, as all of the tiny pock marks, chips and cracks become even more noticeable after you replace it with a perfect new piece of safety glass.

The new windshield wasn't in the truck for THREE WEEKS before it was ruined. I was driving on GBT going 70 mph and a big 18 wheeler kicked up a huge rock and POW! It popped the front glass on the passenger side and I watched as this fixable chip progressed into an 18" long crack over the next 30 minutes of my drive. GRR! Just figures.


Once again, the new state inspection was looming so I had a good excuse to get the windshield replaced. And Jason's 8.1L GMT800 truck just had a huge rock impact in it's front glass also, so we called Titan and they brought two identical new front windshields and changed them both the same day.

We pressed the "easy button" and called Titan to do their thing. Both GMT800 trucks had brand new, quality replacement windshields within about 90 minutes. We will also replace the huge, gaudy front "Vorshlag.com" windshield banner with something new.
OTHER UPGRADES + ANOTHER SWB GMT800 AT VORSHLAG
Most GMT800 trucks came with running lights in the USA, as part of some Daylight Running Light safety program. The trucks either came with the main headlights on during daylight or with small clear lenses that illuminate inside of the amber parking lights.

Well this truck had the smaller Daylight Running Lights, and one was burned out when I bought it. This is super common in the GMT800 series, as my 2002 1500HD had the "cyclops" look for the entire time I owned it (and after trying a new bulb it wouldn't work). Come to find out these trucks often had this light bulb sockets burn out, with some crappy GM wiring or metal fixture in the socket that would always get friend - usually on one side. If you know what to look for you will see hundreds of these GMT800 trucks with one DLR that is always out.

When we replaced the front lights and grill last time I had hoped to fix this issue with new bulbs, but of course that wasn't it. So I ordered the light bulb socket above (ACDelco LS94 Daytime Running Lamp Socket) for $16, and asked our guys to replace it. I also ordered a pair of 3157 style LED bulbs to replace the old ones. I looked for something better than the standard incandescent bulbs and decided to try some "super bright" LED replacement bulbs that were "very white". There was an amazing number of these cheap LED bulbs available with anywhere from 12 to 68 "SMD" LEDs on mounted onto a cluster that mimics the 3157 bulb's shape. Most were $1-2 each, almost all of them shipped from China, and the customer reviews were generally TERRIBLE. I picked one of the 68-SMD units that had 3.5 stars, which was relatively high for these units, for $2.15 for the pair.
It turns out that the bulb socket wasn't bad, and Brad was able to repair the stock socket with a little fiddling (one of the connectors had been mashed down and wasn't making contact). They installed the two LED 3157 bulbs, and, well... they look awful. Nothing even remotely approaching "white light", instead its much more "blue" and just turrible. So if you learn anything from this it is: check the socket to see if it can be fixed, and don't buy these cheesy LED bulbs.

One of our fabricators, Olof, picked up a GMT800 Short Bed Short Cab Chevy a few months back and it looks pretty slick. He bought the truck with the mods shown and it is riding on OEM Chevy 20" truck wheels, is lowered several inches at both ends, and has a Chevy 4.8L V8 under the hood. He's already replaced the steering rack and done some other repairs, so I'll include any updates to Olof's Chevy in the Truck Norris thread when I do updates from now on. Of the 10 people that work at Vorshlag, 3 of us own GMT800 trucks now (me, Olof and Jason).

Last but not least is a Raptor vs Truck Norris comparison. One of our friends (Nathan) picked up this 6.2L Raptor from our local Ford sales guru Corey White and it is damned nice. But, the interesting thing is, Truck Norris gets better fuel mileage, weighs a crapload less, and costs about 1/10th of what the Raptor did. And our GMC has wider tires... so there!

WHAT'S NEXT?
That's all for this time. We still have lots of little things to tweak and update, and someday I'll get around to drop spindles up front and a C-notch kit out back to get MOAR LOW.

With a current inspection sticker, custom engine tuning, and a new windshield, Truck Norris is looking better than ever
Thanks,


























































































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