Hobbs 96 Z71 Build

[Z71Hobbs]

So, I've been a member for several years, and thought it was about time to start a build thread. I've done lots of little things to the truck over the years, but am just now getting into the big changes.

A little history. I've had three gmt400 trucks. My first one was a 93 GMC K1500 ECSB with a 5.7 that I modified with exterior accessories and audio while in high school. It was a two tone teal and silver truck. Overall, the truck turned out pretty good and i started regretting selling it not too long afterwards. I learned about about car audio with this truck, especially that I will never install another set of 4x6 speakers in the rear pillars ever again.

Here is an older picture that shows what it looked like when I got rid of her.

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[Z71Hobbs]

My second gmt400 I acquired in college was a 96 Chevy K1500 with the turbo 6.5 diesel. This was an absolutely awesome truck that I had a ton of fun with. It was nearly fully loaded and had a ton of pep. I ended up trading it during a great GMC dealer truck sale, but nearly instantly regretted selling it. I tried to track it down via carfax and from the best i can tell it ended up in New Orleans, was stolen, recovered, and later died in a major accident somewhere near New Orleans. The last information I had was that it ended up in Lafayette, LA.

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[Z71Hobbs]

And finally my 3rd GMT400, and likely my last that I bought in Nov of 2012. This truck is going to be built the way I'd always wanted to, but couldn't afford to. I looked for nearly a year, and turned down nearly a dozen trucks that I saw in person. I ended up meeting the guy down in Tennessee, and the truck came from Mississippi. This is a 96 Chevy K1500 with the turbo 6.5 diesel. Not quite the color combo as my last one that I dearly miss, but it is rust free and only had 135,*** miles. Aside from from some dented bumpers, some small door dings, and the failed paint on the roof, the truck is a solid truck. Here is what she looked like when I brought her home.

So, it appears that I am a sucker for a two tone paint job.

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[Z71Hobbs]

So now that the history is out of the way, here is a quick list of things that have been done. Some of you might have seen me posting on dieselplace.

In March of 2013, I was working in the back yard and had the truck sitting off to the side of the house idling, when it died. Checked fuel flow, and the other basics. All checked out. So I plugged in a spare pmd I had picked up used, and it got me going again. The previous owner had relocated it to the driver side of the engine bay, which should have worked for longer than the mileage that was put on it. Not sure why it didn't last as long, but the pmds are finicky.

Not too long after that, I was driving down the road and the spare pmd I had used as a quick fix also died. So, I ended up ordering a new kit off of ebay with a #9 resistor for more fuel that relocates it to the front bumper. So far, that has fixed the problem!

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[Z71Hobbs]

So, because funds are slow, and I have young children, I don't get to drive the truck daily. Toddler Car seats and extended cabs without a third door don't work so well. So instead, I scour the net and find spare parts for my truck. During my travels to craigslist finds, ebay, and this site, I have picked up several items. Some of the most important items were the K47 Airbox, and a non egr upper and lower intake manifold.

So after a few months, I decided it was time to change out some things on the truck. The first thing I did was cut out the old exhaust and soot trap and install a new diamond eye turbo back exhaust kit. I completed this install at the same time as putting in new bosch injectors, and new duraterm glow plugs. Once I had all these items on, I noticed I could not get my turbo spooled up so well. So after a bit more troubleshooting, I came to the conclusion that my vacuum pump wasn't sucking so good! So, that got swapped out with another delco. When I pulled the last one out, it was rattling and dropping metal pieces. It was shot!

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[Z71Hobbs]

Here is a sample picture of why I changed out the exhaust system. The downpipes on the 6.5 up through around 1998 are severely restricted. They look like they were run over by a semi!

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[Z71Hobbs]

And somewhere in there, I noticed that my daytime running light (DRL) icon was illuminated on my gauge cluster, but they were not working! After doing some internet research, I discovered that it is common for the large resistor under the dash to fail. So 4 dollars later at the pick n pull, I have a good used one. A little trick I read about was bending the tabs on the bracket holding the resistor and sliding the resistor down over the bent tabs. The whole process took about 5 minutes!

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[Z71Hobbs]

After getting the injectors and glow plugs replaced, and the new air box and exhaust, the truck was running a bit better, but was still not as peppy as I thought it should be. So I pulled the upper intake and performed a mild surgery to help increase the air flow. Holy cow! This was by far the best modification I had done to the truck, or possibly just allowed for all of my other improvements to work out better. The factory egr intakes on these trucks are severely limited in terms of airflow. Here is a before and after pick.

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[Z71Hobbs]

So after enjoying the combination of the upgrades, I decided it was time to get a tune performed. I wanted to get a tune to remove the egr programming from the trucks computer, to increase the fuel rates to the motor, and modify the shift points. I ended up getting a KOJO Tune. All in all, it wasn't bad, but not as much as I had read it was hyped up to be, especially after waiting 10-12 weeks to get it. Immediately prior to installing the new tuned pcm, I swapped the lower intake out to a non-egr intake I had picked up. Because I have ocd about putting greasy parts back on my truck, I sandblasted the non egr upper and lower intakes clean. I am not a fan of the raw metal look, but dont want shiny polished aluminum on my motor. I am more of a bright cast aluminum finish kind of guy. So, I grabbed a bunch of brass brushes and brushed my heart out until I got the finish I was seeking - it took several brushes and a few evenings, but it turned out pretty good. In the pic below, the upper intake has been brass brushed, while the lower intake was still raw from sandblasting.

Funny thing, when I purchased a new set of fel pro intake manifold gaskets that have the egr port blocked off. When I pulled the lower intake, I found out that the previous owner had already put block off gaskets in it!

At this same time, I installed a Feed the beast modification to a new old stock ffm I picked up. It is a nice kit. This changes the output from the fuel filter manager from 1/4" to 3/8" to match the line from the lift pump.

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[Z71Hobbs]

So, I had my new intakes, my KOJO tune, and I couldn't get my truck to run for more than 1 minute without choking itself out. I changed out the lift pump, and dropped the tank to install a new tank sock (the correct diesel one). None of that helped. After a lot of troubleshooting, I had a bonehead moment. In my effort o make installing the FFM housing easier, I used a slightly longer piece of rubber fuel line that kinked on itself once it was mounted. So while I probably didn't need to drop the tank, or change the lift pump, I'm happy I changed them as I probably wont have to for a long time.

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