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

[Rocket Man]

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:

View attachment 347793

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.

View attachment 347794

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.

View attachment 347802

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.

View attachment 347803

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.

Good luck!

 

[Teamiez]

Because it's an Aztek! There's probably only 10 windshields left!

That’s why Walter white waited so long to replace his as well

 

[Keviebear86]

Changed up the front end. I was washing the truck and some of the chrome peeled off the factory grill so I got this black one and a black bow tie. Looks much better (even though I think the fitment sucks). Next up is black bumpers and tinting the front windows.

 

[Rocket Man]

Changed up the front end. I was washing the truck and some of the chrome peeled off the factory grill so I got this black one and a black bow tie. Looks much better (even though I think the fitment sucks). Next up is black bumpers and tinting the front windows.

Looks good from here!

 

[Tonyrodz]

Changed up the front end. I was washing the truck and some of the chrome peeled off the factory grill so I got this black one and a black bow tie. Looks much better (even though I think the fitment sucks). Next up is black bumpers and tinting the front windows.

You also could've dipped your chrome grill.

 

[Keviebear86]

You also could've dipped your onestly that thought never crossed my mind.

You also could've dipped your chrome grill.

Haha. Yeah, never even thought of that. I still have my OE grill so I may end up doing that.

 

[Tonyrodz]

Haha. Yeah, never even thought of that. I still have my OE grill so I may end up doing that.

Yup. You already have the grill, plus it's oem so it'll fit great.

 

[Fless]

Took it out for an evap drive cycle after fixing the evap leak by replacing the fuel pump gasket. The money light went out before I hit the 3 mile mark on my drive, but I kept on going for the joyride!

 

[Rocket Man]

Took it out for an evap drive cycle after fixing the evap leak by replacing the fuel pump gasket. The money light went out before I hit the 3 mile mark on my drive, but I kept on going for the joyride!

That’s awesome, great news.

 

[Fless]

That’s awesome, great news.

Now to run some of this new gas out and top off with E85 sometime next weekend.