Anyone running an S10 Blazer fuel tank?

[baileynb]

I'm trying to research the S10 Blazer fuel tank swap. The tank in my '72 Wagoneer is pretty beat up, has a shady looking patch, and I get occasional stains on the driveway. I've looked and it does not appear that the fuel is running down the side of the tank, the sides are dry but I've got drips from the bottom center of the tank in the flat spot on the deeper portion and a little up on the shallower section. I need a tank regardless and have read mixed reviews on the plastic replacements. I'm also going to be installing a Howell TBI system and read the Blazer pump will work for it.

So, my question is, how is the tank plumbed for venting? The Wagoneer's manual shows a lot of venting lines and looking at the S10 Blazer tank I only see the pump/sending unit hole and the fill port. I do see three ports on the fuel tank, is one of those for venting?

[SJohn]

There is a 5/8" vent next to the fill hole, I have it plumbed to the fuel filler.

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[tgreese]

Hi - Howell TBI is the GM Rochester system, adapted to your engine and application. This system requires a return line but you can use the factory 5/16" feed and 1/4" returns.

Does your Jeep have fuel tank vapor emissions control FTVEC ie an expansion tank in the rear quarter? V8s also came with a charcoal canister under the hood if so equipped. Some '72s had it (California? Looks like it was nation-wide.) and some did not. The S10 tank will have a vent in addition to the fuel pickup and return that's meant to connect to the FTVEC system. You can cap those vents and use a vented gas cap if you want. Suggest small lengths of high-quality fuel hose with a solid plug in lieu of the aftermarket caps sold for that purpose. The caps will only last for a few years at best.

Are you looking at the '72 TSM? Chapter 4 figure shows the plumbing for the Wagoneer tank. You will see a vapor separator. It's meant to keep any liquid gas out of the FTVEC system. The black line going to the front of the car takes the vapors to the charcoal canister under the hood. The other 3 lines go to each corner of the tank to collect vapor and possible some liquid. This is meant to make the air pocket above the gasoline always communicate with the FTVEC system, regardless of the Jeep's attitude.

Your replacement tank will have some kind of vapor vents. All modern car's fuel tanks will have this. Sometimes the plumbing to access the air pocket is inside the tank, and you'll have only one vent nipple, or maybe two. All of these should connect to your vapor separator tank nipples. Any left-over nipples on the vapor separator can be plugged.

Looking at pictures of the S10 tank, it appears that the vapor connections are on the sending unit / fuel pump. I would expect that the 3/8" tube from the fuel pump is fuel feed, the smaller line to the bottom of the tank is return, the smallest line with the bell-shaped valve(?) is vapor, and the largest connection goes to the filler neck.

[tgreese]

Also it looks like there's no fuel return line on a '72. You'll have to add that - the EFI needs it.

Despite what the Howell instructions say, I suggest you use steel line for the new tank installation.

[baileynb]

Yes, I was looking at the '72 FSM and the fuel diagram. Like I said, a lot of evap/vent lines besides the fill vent. I was mistaken on the fuel pump I was looking at, there's 4 lines. Looks like supply, return (and I already knew I would be installing a return line for TBI), vapor/evap, and vent.

SJohn, how did you secure the tank and connect the hoses for the filler. I keep reading that the filler pipes are different sizes. I know someone on another forum was making custom hoses, but I've been having issues on that forum with posting (it barely even loads on my tablet). As far as security, I've seen someone post a part number for a longer set of tank straps, but I haven't been able to see pictures or instructions for how to safely secure it. Most of the posts seem to no longer have the photos available or only show the finished install.

[SJohn]

Yes, I was looking at the '72 FSM and the fuel diagram. Like I said, a lot of evap/vent lines besides the fill vent. I was mistaken on the fuel pump I was looking at, there's 4 lines. Looks like supply, return (and I already knew I would be installing a return line for TBI), vapor/evap, and vent.

SJohn, how did you secure the tank and connect the hoses for the filler. I keep reading that the filler pipes are different sizes. I know someone on another forum was making custom hoses, but I've been having issues on that forum with posting (it barely even loads on my tablet). As far as security, I've seen someone post a part number for a longer set of tank straps, but I haven't been able to see pictures or instructions for how to safely secure it. Most of the posts seem to no longer have the photos available or only show the finished install.

I mounted my tank in the spare tire location and you can see the pictures on my build thread in the builds section here. Since I'm also running my factory tank as an auxiliary tank I put the filler inside the bed using a spare filler off another J truck. The blazer tank has a 2" filler so I modified the Jeep filler to adapt up to 2" with a piece of exhaust pipe welded to the filler. The vent fittings are the same on the tank and filler.

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[baileynb]

Thanks, I'll take a look at your build thread.

[AMCdealer]

As thirsty as my FSJs have been I thought about trying to squeeze a 44-gallon Ford Excursion tank in the spare tire area.

[baileynb]

I've read where people have put in Ford E-Series vans that are much larger, I think 30 gallon range? I'm fine with 20 gallons, it's only a gallon or two less than the factory tank.

I'm worried enough paying to fill up 20 gallons, I can't imagine standing there watching the price roll up filling a 44 gallon tank. The longer trip between fill-ups is nice, but if I have a long distance drive, I've got my 88 Mazda with a Mazda DOHC fuel injected engine swapped in that gets high 20's mpg and about 4 hours between fill-ups or if my girlfriend is with me, I'm sure we'd be taking her 2022 or 2023 (can never remember) 4Runner.

As an update, I haven't gotten much done besides ordering the tank and pump and some tank straps. I had to chase down a couple of post-install issues on the Mazda's engine rebuild. I did take the receiver down and cut the square tube off the front and rear cross member sections of the receiver. I need to grind the remaining weld sections down then clean and paint them. I plan to reuse them as cross members for the tank straps to secure to and maybe build an ABS skid plate that I can use to attach as well.

The factory fuel tank finally stopped leaking, the level must have gotten below the failed patch. I had a five gallon bucket underneath to catch the fuel. Over a couple days, I was transfering it with a large measuring cup over to my gas can. Luckily, we were hauling a lot of river rock around the property with the Cub Cadet, so I was able to keep it filled up and didn't need another gas can...