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

[rayra]

My 1/0 cables were just shy of 1/2" OD and the PVC conduit had a 5/8" ID, 7/8" OD. The cables were thick strand residential / commercial wiring, not fine-strand welding wire and were pretty stiff. Cable in conduit even moreso and the under hood aux location didn't leave enough room for a 'snorkel' or weatherhead type arrangement. I ran the conduits up between the firewall and wheel well tub to just about the height of the aux battery tray then wrapped shimmed the cables with electrical tape, squeezed some 100% silicone in the conduit ends and wedged the tape wrap into the conduit ends like a plug.
The other end, I used junction panel compression fittings on the conduit, mounted to the cargo floor penetrations to seal the other end.
When I resized the subwoofer box to make room for the penetrations between the sub and rear wheel tub, I arranged things for the future rear bumper power connector cabling to pass thru the same area in the same manner. So four cables / conduits, in a square pattern, in a tight spot in the cargo area behind the interior trim panel.
The rotary cutoff in the aux power box in the back is primarily there to cut power to that rear bumper plug. Although I'm currently using it to isolate a 1000W inverter.
I'll do the same to a front bumper power plug as well.
Eventually I intend a 9k or 12k-lb winch on a receiver hitch carrier, which can be attached at either end of the vehicle, served by this 1/0 cable / power bus.
I also still want to modify a good long set of heavy duty jumper cables with the same sort of Anderson SB250? connector pair near one end, so in the future I can just plug the cables in at either bumper, for more reach and convenience. Mil trucks had (have?) a similar arrangement called a 'slave cable' for jumping one from the other without having to get to the batteries. I'm sure the PC army calls it something else nowadays.

 

[Lykos]

About how many feet of conduit did you use?

 

[rayra]

somewhere around 17-18' x2. IIRC a 50' roll was the best bargain. Took a bit of work to get it uncoiled and straightened out, lot of time in the sun and hand-working it helped. I loaded the cable in it before I worked it into place. I also soldered the lugs on the battery end of the cables before feeding them into the conduits. I started next to passenger side of the vehicle and worked the front ends in first, getting that end bent into place, some anchors and got the cables positioned for attachment to the battery, but not connected. Twisting the heavy cable is also problematic, so get the lugs / conduit position properly and positioned as best you can, before wrestling the rest into place. .
Watch your routing when you get around the muffler, stay as clear of it as you can. I've got no heat discoloration of my conduit, despite lots of Socal summertime bumper to bumper traffic jams, so I must have done something right.

There's a bunch of pics and words in my 12v topic when I did the work.
https://www.expeditionportal.com/fo...-inputs-on-my-inputs-and-ouputs.161657/page-6

 

[rayra]

This guy REALLY needs to read this topic, it could save him $1000s. His two problems would cost $20 and a couple hours to repair.
https://www.ar15.com/forums/General...anics-a-moment-of-your-time-Please/5-2220167/

 

[rayra]

He REALLY does. Now his shop wants him to rebuild the bottom end. Nobody posting in the topic has a clue about the common cheap to fix issues which are almost certainly his trouble.

https://www.ar15.com/forums/General...-moment-of-your-time-Please/5-2220167/?page=2

HEY CODESMITH AR15.COM!

 

[fl0w3n]

@rayra does your 1500 burb have the 36 gallon dual tank setup? Have you replaced the fuel sending unit?

Our 2500 burb just left us stranded on a trip last week. Reported half tank of gas, acted like it was out of fuel. No fuel pressure at the injector rail, or only minimal pressure after key on/off a couple times. I'm thinking it was worn out and then it didn't like the 108* heat and grades for hours and died.

I'm wondering if both tanks need to be pulled, and how much of a PITA it is. I figure at the same time replace the charcoal canister and what ever other emissions crap is hanging off the tanks so that we can fill it up normally at a pump.

 

[rayra]

@fl0w3n sorry, the 1500s have a 32gal single tank. But it should all work the same as yours. You just need to drain and pull the tank that has the fuel pump mounted inside.

Heat is usually what kills them. Especially try to keep at least a quarter tank in the hot months, as the pumps are literally cooled by the fuel surrounding them. Run them hard with a near-empty tank and they can go any time.

I don't know if the fuel pump location is the same on the 2500s, but would expect that it is. GM doesn't re-engineer things unless they have to, making their money on economies of scale and using identical parts every place they can. You should be able to get under from the passenger side by the driveshaft and see well enough with a light / mirror or cellphone camera and confirm the pump is under the 2nd row driver side seat. And then could use the thru-floor technique described earlier in this topic. Or can just drop the tank in the driveway.

 

[fl0w3n]

I’m wondering if the second tank is just gravity fed only? Gmparts direct and rockauto come up with a few different options for part numbers for the pump.

You mean cutting a hole in the floorboard to access it? Maybe, I’m kind of over the Burb so I just might do that. Carpet could be replaced anyways. Tank is half full and I don’t wanna deal with dropping that.

My Duramax is my priority right now, and it still needs plenty of work. Don’t wanna take away any more time than I have to from it.

 

[Overlandtowater]

I’m wondering if the second tank is just gravity fed only? Gmparts direct and rockauto come up with a few different options for part numbers for the pump.

You mean cutting a hole in the floorboard to access it? Maybe, I’m kind of over the Burb so I just might do that. Carpet could be replaced anyways. Tank is half full and I don’t wanna deal with dropping that.

My Duramax is my priority right now, and it still needs plenty of work. Don’t wanna take away any more time than I have to from it.

There is replacement pumps for the 2nd tank on rock auto but I have heard conflicting comments about pumps and gravity to transfer the fuel. I would like to install the 2500 2nd tank into my 1500 when the time is right. I dropped my fuel tank with a 1/4 tank in it, no problem and if you have to cut out one of the strap bolts replacements are cheap...don't cut the strap they are like 50 bucks and the bolts are 5. To drop the tank I used 2x6 on top of jack stand and back to drop one end at a time...putting it back up is the harder part you need to lift the truck high enough you can put a creeper of something under the tank to slide it back in.. I laid under the tanks and slid back under with the tank on more than one vehicle but not everyone is as dumb as me.

 

[Buddha.]

Sometimes removing the drive shaft makes dropping the tank easier, not sure about the Suburbans.

 

[rayra]

Makes it easier if you are on the ground, but there is enough room to not have to. But it's easy enough, just 4 bolts to remove. Aim the nose downhill and you won't even need to plug the tailshaft opening. But the plastic temp plugs are inexpensive and very handy.

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And it's not very difficult to siphon the fuel out of a tank you are dropping. You're disconnecting the filler hose anyway. Just do it first and get $10 worth of 3/8 or 1/2" ID clear PVC hose. And we've all got fuel jugs, right? Right? In fact get 1/2" ID and you can pick up a couple 'SuperSiphon' devices to use with the hose in the future.

It's just a long day wrasslin' with a fuel tank in the driveway. None of it is particularly difficult. Just tedious. More so if you are in a high rust region.

 

[lilkia]

I’m wondering if the second tank is just gravity fed only? Gmparts direct and rockauto come up with a few different options for part numbers for the pump.

You mean cutting a hole in the floorboard to access it? Maybe, I’m kind of over the Burb so I just might do that. Carpet could be replaced anyways. Tank is half full and I don’t wanna deal with dropping that.

My Duramax is my priority right now, and it still needs plenty of work. Don’t wanna take away any more time than I have to from it.

On the gmt800 2500 the larger main tank is gravity fed through the smaller tank. . The smaller tank has a fuel pump i believe it feeds the engine first and when it runs dry the main tank pumps kick in.

 

[rayra]

seems like the engineering is kinda backwards. two pumps, too?
If I were to wind up with two tanks I think I'd rather have the smaller be the aux / secondary and have it plumbed with a transfer pump, like a reserve. From an off-road / 'expo' perspective I'd rather the second tank not drain out - too - if the primary is punctured. As it would with a 'gravity feed' setup.

I have dual tanks in my '85 C-10, they are manually switched via a fuel line valve/solenoid and a dash switch. Ever since the Northridge quake caught me without any fuel on hand, I've kept at least one of those tanks full at all times, alternating their use. Whenever I need to switch to the full tank while on the road, I fill the emptied tank as soon as it's convenient. So I've always got something like 1/2 the total fuel capacity aboard. 25yrs+ I've been doing that.
And now with the Sub, I've made provision for up to five 20L jugs of water or gas in the vehicle, as well as a hitch rack for emergencies. And I keep ~50gal of both water and fuel in ~20L jugs.
Taking a drive thru Death Valley and up around Mono late next month, probably taking more water than gas.

 

[tacobronco]

@rayra does your 1500 burb have the 36 gallon dual tank setup? Have you replaced the fuel sending unit?

Our 2500 burb just left us stranded on a trip last week. Reported half tank of gas, acted like it was out of fuel. No fuel pressure at the injector rail, or only minimal pressure after key on/off a couple times. I'm thinking it was worn out and then it didn't like the 108* heat and grades for hours and died.

I'm wondering if both tanks need to be pulled, and how much of a PITA it is. I figure at the same time replace the charcoal canister and what ever other emissions crap is hanging off the tanks so that we can fill it up normally at a pump.

Ours did the same exact thing, although ours had the common decency to quit less than 5 miles from home after driving 300+ miles that day. After letting it cool for a few minutes, it restarted, and we made it home. It was in the middle of summer camping season, so I did what I rarely do - let a shop work on my truck (after a bunch of research). Apparently this is a pretty common failure mode for these trucks once they reach a certain age/mileage. There is only one high pressure pump, and it's in the "main" tank (the one mounted under the driver side rear seats, not the one under the rear cargo area). Not sure how the truck manages the transfer from the rear tank to the main (gravity or pumped), but I was assured that there is indeed just the one pump feeding the engine, and I could tell they only dropped the front tank. Been fine ever since.

 

[britome]

Looks like this is a general discussion on a variety of topics? If not, sorry for the ask...

I’ve got a 2011 Silverado 2500 with 6.0. It started out as a “cheap” overland vehicle since it is the one I already owned. After having CO and Imogene pass with it, I’m very impressed. It will be with me for a while. Two things I would like to solve...

1) larger tires. What are the downsides or upsides to doing a leveling kit so I can go larger?

2) mpg sucks. I’ve had full time up, replaced injectors, plugs and wires. Put on a cold air intake, etc. I just can’t get above 10.5 in City or 12.5 on highway. Does anyone have any exhaust suggestions? My motorcycle used to get awful mileage. Then when the headers got dented off-road and I had to replace them, I found out the cat must have been bad since fuel economy sky rocketed.

Any insights any of you can give me would be appreciated.

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