What did you do to your NBS GMT800 Tahoe/Yukon Today?

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Rolexus

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I have a 01 yuk 4x4, and a few days after I bought her, the svc 4wd light started coming on every once in a while. Didn't do it everyday and at times wouldn't come on for weeks at a time. Did some research and learned that it was possibly the 4wd selector switch. I ordered one off of ebay and put it on Saturday. Keeping my fingers crossed that I won't see the light anymore. Replaced it because it started coming on more frequently.

Also tried to remove my rear fog lights but the bolts are so rusted had to stop because it got too dark. Will try to finish it this weekend.
 

Rolexus

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Hey Bud, don’t be surprised if the new dash switch doesn’t work. My 05 Tahoe had same issue 1 yr ago. I replaced switch, all good, until recently. Watched YouTube video. Someone posted lengthy analysis. His solve worked for me.

I found the ‘4 wire’ harness attached to plastic inner fender
3ADCB985-C9B5-49F4-AE2F-3D68B5A19ED7.jpeg
on drivers side. GMC notorious for bad grounds. I found the solid black wire leading from this harness, spliced my own (blue) wire to this solid black wire, and ran it to the firewall. Pics attached.

****! Problem fixed. Hope this helps.
40749CDF-3174-44FD-A40A-21830F3F110C.jpeg
3BE35794-07EB-4BEC-B2BC-6C95E8DB5A76.jpeg
 

Fless

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Yesterday, I put her up in the air, relieved the fuel pressure, and pulled the driveshaft, evap canister, and the evap connections. Schedule permitting, tomorrow morning after church my son (Nate) and I will drop the tank so we can install a new fuel pump gasket to fix the evap leak. Hopefully we'll be able to tell what went wrong with the new gasket we installed two years ago with the new fuel pump (all AC Delco Gold/Pro). Note vintage homemade creeper in the foreground.

2021-08-14_Tahoe ready to drop tank_resized.jpg
 
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Doubeleive

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Yesterday, I put her up in the air, relieved the fuel pressure, and pulled the driveshaft, evap canister, and the evap connections. Schedule permitting, tomorrow morning after church my son (Nate) and I will drop the tank so we can install a new fuel pump gasket to fix the evap leak. Hopefully we'll be able to tell what went wrong with the new gasket we installed two years ago with the new fuel pump (all AC Delco Gold/Pro). Note old homemade creeper in the foreground.

View attachment 347671
@SS UP FACE DOWN!
 

corvette744

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Yesterday, I put her up in the air, relieved the fuel pressure, and pulled the driveshaft, evap canister, and the evap connections. Schedule permitting, tomorrow morning after church my son (Nate) and I will drop the tank so we can install a new fuel pump gasket to fix the evap leak. Hopefully we'll be able to tell what went wrong with the new gasket we installed two years ago with the new fuel pump (all AC Delco Gold/Pro). Note old homemade creeper in the foreground.

View attachment 347671
Nice creeper i would cut piece of memory foam and glue it to that and might fall asleep on it when under their.
 

Teamiez

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That's a big chip, almost a hole. How does the rock always manage to make a chip exactly in your line of vision?? A sniper isn't even that good.
That’s how the one on my passenger side is haha...one week after a new windshield install. Only reason for new windshield was the seal was leaking water down the pillar onto passenger floor
 

Teamiez

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Places here won't fix it if it's in the line of sight, which is basically a license-plate-sized rectangle directly in front of the driver's head. Might be a state law. There's a great chance of vision distortion with the repair right in front of you, and that will be most noticeable at night. Recommend getting a name brand windshield; I don't think you can go wrong with Safelite. I had glass insurance on mine when I had it replaced.
Safe lite did mine 0 complaints except the rock that chipped the glass a week later on a county road
 

Scottydoggs

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hard wired a power port in the hoe today. ran it to the glove box. my mothers portable oxygen machine was blowing the stock power port fuse in minutes even with a 30 amp fuse in place. new hard lined port works flawlessly now. thank god, what a pita not being able to keep that damn thing charged was.
 

Fless

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Finally got around to replacing the fuel pump gasket that has been leaking and caused the evap drive cycle failure. After shotgunning parts (purge valve, vent valve, canister) we got serious about troubleshooting it and it came to this. We used a smoke machine for a coarse diag, and a little air pressure after narrowing it down.

We (my son Nate and I) replaced the fuel pump about two years ago, using an AC Delco Pro/Gold pump, which included the gasket for the Flex Fuel pump. We're not sure if we messed up the gasket when installing, or if it was received that way. And we're not sure why it didn't fail evap back then; it's been good until about two months ago. I don't recall that we had to install the gasket on the pump that time, I think it was already on it. Anyway, now to get some gas to get it up to half a tank and run the evap drive cycle.

The gasket seems to have rolled a bit, or was malformed. You can see in the pic where it was leaking, all along the part with the light residue. The red triangle points to the start of the defective part, and it goes to the right several inches:

2021-08-15 Fuel Pump Gasket_resized.jpg


Here's a comparison of the old (upper pic) and the new (lower) gaskets. The new one (also AC Delco) is a less pliable material and looks like it will hold form better.

2021- 08-15 Fuel Pump Gaskets_resized.jpg


There is a strainer that slips into the tank filler stub, maybe to prevent siphoning? It just slips in and out but is the exact size for the inlet.

2021-08-15 Fill Tube Screen_resized.jpg


And, lastly, the pump and new lock ring as installed. To remove the old ring and install the new one we used channel lock pliers to put pressure between the ears on the tank and the notches in the ring. We did this on opposing ears with two pliers and so no hammer or punch needed.

2021-08-15 Fuel Pump New Ring_resized.jpg


So, on to a few test drives over the next week or so. Glad we were able to confirm the cause of the leak with the physical evidence.
 

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