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L83 5.3L E85 conversion. OEM fuel lines, no splice. Warning inside.

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Well, after reading the fine print in my extended service plan for my truck, it says no after market, alternate fuel conversions. Now considering mine was done with a GM sensor and GM's own software (stock ecu edited with HP tuners), but it had after market compression fittings, I was worried (I think my HPFP) is leaking. So I decided to put an oem feed line in so there was no contest to the validity of the oemness. 


As far as parts, I have a 15' ccsb. All I needed was 4 lines and a new sensor that hadn't had compression fittings on it. The lines consist of a steel line at the tank, a short plastic line, then the sensor, another short plastic line, then a long steel line with a short rubber section in the middle. 


Removing mine wasn't too bad. It already had a cut in it from where the sensor was, so the back half came out fine. The front half on the other hand, I spent about 2.5 to 3 hours total on this and over an hour was figuring out how to get the front half of the line out. First, the abs module. It's held on by 3 bolts from the outside of the frame  Completely remove the bottom bolt and leave the top two in by the last thread. Unplug the fuel sensor plug (its close to the abs unit on the fuel line) and undo as many clips on the line as you can. Then under the hood on the left side valve cover, you can see a rubber line towards the back, that's the fuel feed. Gently pry off the safety clip and use a fuel line disconnect tool to remove the line. (I disconnected the tank end first to drain so I didn't get fuel on the engine) Next, this is the part that took me an hour to figure out. First, drop the front end of the front drove shaft, it's only 4 11MM bolts and move it as far right as you can. Now, there is a bracket bolted to the trans by a single 13MM nut. I used 2 12" extensions and a deep socket to get to it, by running along the top side of the trans. It's up high and hard to see. The bracket had a rubber or wax coming on it and it should be the only thing holding the lines together and in place at this point. The battle is not won by simply unbolting it however. Some genius decided that it needed to be metal and folded over itself. After 30 minutes of studying this, I wedged my dremel up there with a cutting disk and carefully cut it until I was able to pry it open with a screw driver. Now the lines are free and should be finessed out. I have no tips on this, this isn't the proper way to do this. After the line is out, it was time to put the new line in. The new line is shorter than what came out but a huge pain to put in. I'm concerned for the condition of the rubber hose on mine, but what's done is done. (Twisted and kinked) I also have no tip for putting it back in. 


The advice I have is that the left cab bolts should probably be removed and the right loosened so the cab can be lifted a few inches on the left side. The will possibly make removing and reinstalling the lines easier.


Overall, do I recommend doing this, not unless necessary like mine was, or if you aren't comfortable with the compression fittings. I first used dorman high pressure steel fittings and they leaked regardless of what I did. Then I went with standard brass plumbing fittings and had no issue but had lost confidence at this point. I feel better knowing that it's done as it should have been from the factory, minus the one bracket I cut off. 


To order the parts I literally copied the vin off a 2014 truck in the parking lot at the dealership and provided it to the parts guy. I told him what I wanted and he sent me the attached screen shot to confirm. Nothing else was needed. 


I forgot and am not editing this in, there is a bracket for the sensor and the holes are in the frame for it. I didn't get it, but I probably will.


For my 2015 5.3 denali, crew cab, short bed, I used this: 


Year: 2014
Make: Light Truck
Model: Silverado / Sierra / Cheyenne Light Duty - 03, 43, 53 Bodystyle (4WD)(New Model)

© 2022 General Motors




Screenshot_20220112-232435_Acrobat for Samsung.jpg

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I would be more concerned about having flashed the ecm.


Before I made modifications I resigned to the fact that I would loose my warranty. When I made it my truck, it was no longer GM's truck; and turn they had no obligation to provide warranty on the modified/associated parts. 

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