Hey Vortec Guys! / Sierra pickup / Suburban / Yukon etc - Finally has Index!

[Lykos]

Yup. There's two things you don't mention within earshot of a GMT800, rust and fuel pump. No...

The problem has self corrected for the time being. The ambient temp in Virginia has warmed to above forty. LoL In the mean time I'll get the fuel filter changed and run some injector cleaner through the next couple tanks of gas, check the fuel rail pressure etc.
Thanks sir!

 

[Martinjmpr]

I would bet its the intake gaskets. The plastic with slightly contract when it is cold which is why it only happens then. Ive had a lot of vacuum leaks that i couldnt find with carb/brake clean so i wouldn't necessarily rely on that. If you do the gaskets you should probably also do the knock sensors and harness at the same time as they are also a common failure point. Good luck and dont light it on fire

FWIW my '04 'Burb started throwing a code right after I bought it (which - now that I think about it, was in December after a prolonged cold spell!) Can't remember exactly what the code was but it turned out to be a leaky intake manifold gasket.

Luckily for me, we live in an emissions-control county and per Colorado law, a dealer can't sell a vehicle that won't pass emissions (which it wouldn't throwing a CEL.) So I was able to take it back to the dealer and they fixed it on their dime with a new intake manifold gasket. Hasn't had so much as a hiccup since then - almost 2 1/2 years and 30,000+ miles.

 

[Stryder106]

Do NOT mention "fuel pump" anywhere near anyone's GMT800..............................ever.

 

[Lykos]

Do NOT mention "fuel pump" anywhere near anyone's GMT800..............................ever.

Now I want to change my "f" words just in case.

 

[Martinjmpr]

Let me throw this out there: Would it make any kind of sense to pre-emptively replace the fuel pump?

The reason I ask is that my 'Burb is at 170k now and I'd like it to last at least 2 more years and ~ 30k more miles. The fuel pump seems to be a major "single point failure" that can go with little or no warning. I'd hate to be in the middle of BFE and have it go out on me.

Seems better to bite the bullet and have a known good unit put in when I can do it in town and at a shop of my choosing rather than having it fail in the middle of Resume Speed Idaho and having to have Cletus Spucker's "special" cousin put it in for me at the Circling Buzzard Auto Repair Shop and Moonshine Distillery.

Or am I worrying for nothing and this is really only an issue that affects a few vehicles?

 

[Hillbilly Heaven]

In my experience you are on borrowed time.

 

[Lykos]

Let me throw this out there: Would it make any kind of sense to pre-emptively replace the fuel pump?

The reason I ask is that my 'Burb is at 170k now and I'd like it to last at least 2 more years and ~ 30k more miles. The fuel pump seems to be a major "single point failure" that can go with little or no warning. I'd hate to be in the middle of BFE and have it go out on me.

Seems better to bite the bullet and have a known good unit put in when I can do it in town and at a shop of my choosing rather than having it fail in the middle of Resume Speed Idaho and having to have Cletus Spucker's "special" cousin put it in for me at the Circling Buzzard Auto Repair Shop and Moonshine Distillery.

Or am I worrying for nothing and this is really only an issue that affects a few vehicles?

I see the fuel pump as a maintenance item like any other. Given it's proclivity to go out without notice I'd go ahead and replace it with a quality unit. Doing so is on my own short list before I go anywhere remote (ish).

 

[rayra]

It's been on my list of desired things to do, just been chasing easier stuff. and I sort of have the missus' Tahoe as 'scout', about to turn 200k mi on it.
Much earlier in this topic I did some research on it and found some useful vids on just where to cut thru the floor (basically under the 2nd row driver side seat) instead of trying to wrestle out that big fuel tank in my driveway.

 

[XJLI]

I dropped the fuel tank on my Silverado and it was much easier than I expected. Out in probably 45 minutes, back up in half the time. On the ground with a near empty tank, with a buddy helping stabilize.

 

[Hillbilly Heaven]

Silverado is easier than that. Remove driver's side bed bolts. While you are at it unplug the wiring harness for the tail lights and the harness for the trailer and license plate lights. Loosen almost all the way the bed bolts on the passenger side but do not remove. Use a floor jack and jack up the driver's side of the bed. You can tilt the bed enough to place jack stands between the frame rails and bed. There is plenty of room to get to the tank.

The Suburban you have to pull the tank. The idea of cutting an access hole is not a good idea for safety reasons. Once the tank is out then cut the access hole for later use.

 

[Stryder106]

I'm going to be cutting an access panel in my floorboard above the fuel pump to make a trail fix easier should the need arise. On another note, I've smoked two fuel pumps in 16 years - and each one of them gave warning. Turning the key on, the "whirrrrrring" sound from the fuel pump was MUCH louder than normal - within a week it was dead. Exact same pattern with the second one.

Another observation, my factory fuel pump lasted 12 years, while the aftermarket Airtex lasted 2 years. I now have an AC Delco factory pump back in it.

 

[Lykos]

These trucks are nothing if not interesting.

While ubering tonight I'm sitting on the street pecking away at my phone. The key is in the acc position, radio is on.

The dome lights blink on. Blink blink.


Ok....

Later with the key in the off position the dome lights blink on. Blink blink.


Any idea what this is? Is it a warning? A gremlin? The NSA listening through my deactivated Onstar?

 

[rayra]

There's a 10min(?) timeout after vehicle shutdown, if you just sit in it key off, radio etc on and dont open the doors everything will eventually turn off. Maybe the key on to acc is telling the body computer to leave stuff on, but you are getting the light flicker as that cycles?

 

[tbisaacs]

There's a 10min(?) timeout after vehicle shutdown, if you just sit in it key off, radio etc on and dont open the doors everything will eventually turn off. Maybe the key on to acc is telling the body computer to leave stuff on, but you are getting the light flicker as that cycles?

+1 It’s the timeout. I used to leave my lights on at camp and they’d blink before shutting off.


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[Lykos]

Sounds good to me. Thanks guys!