Do's and Don'ts of Fuel Cells

[YJJPWrangler]

In the final stages of cranking the Willys and I need to address my fuel delivery system. I have a fuel cell that came with the jeep and would like to utilize it. First time messing with a fuel cell and I have some questions. Here is the tank in question.

The port on top is for the fuel gauge. There is nothing else in the tank. There are two ports on the bottom for fuel delivery.

I am planning on running a fuel filter/pump/filter combo but am having issues visualizing the installation. Additionally, I have two fuel ports on the TBI unit(4.3). Will I need to run 2 pumps/4 filters? Or can I neck both lines down into one and then branch them back out to the TBI unit? Also I know that these tanks need a vent. Would the vent use the filler neck?

Thanks,

 

[Fabrik8]

Do you have a return line or is it a returnless system?

 

[YJJPWrangler]

What you see is what I have. I’m thinking one of the bottom ports is the return/vent line and I can run that to the filler neck. The motor is a 91 4.3l out of a Chevy S10. I haven’t seen any mention of a returnless system. The PO used the same cell with his 4.3l. I just need to figure out how to plumb everything up.

 

[71chevytruckguy]

Was probably vented threw what appears to be the filter neck. All vents I've seen are on the top of the tank.

Also, my personal opinion, don't use an aluminum cell if you wheel hard.

 

[BigSouth]

I’d also consider NOT placing a filter before the pump. From experience, if you clog the first filter, it’ll starve the pump (that’s cooled from flow) and burn it up. Just the one filter, after the pump will suffice.

 

[Fabrik8]

So are the two ports on the TBI both input ports, or is there one input port and one return port?

 

[Fabrik8]

I’d also consider NOT placing a filter before the pump. From experience, if you clog the first filter, it’ll starve the pump (that’s cooled from flow) and burn it up. Just the one filter, after the pump will suffice.

A lot of people do a pre-filter of a larger micron rating, mostly to protect the pump from tank debris. The post-pump filter with a smaller micron rating does the important work for the engine downstream.

 

[BigSouth]

A lot of people do a pre-filter of a larger micron size, mostly to protect the pump from tank debris. The post-pump filter with a smaller micron rating does the important work for the engine downstream.

Oh, I get it, and I’ve done it. Still do it. Just making the man aware. Deep in the woods, I burnt up a pump, and relied on a buddy’s spare to get me out. Now I roll with a spare. Just info to help make his own decisions.

 

[Jeff B]

In the final stages of cranking the Willys and I need to address my fuel delivery system. I have a fuel cell that came with the jeep and would like to utilize it. First time messing with a fuel cell and I have some questions. Here is the tank in question.

The port on top is for the fuel gauge. There is nothing else in the tank. There are two ports on the bottom for fuel delivery.

I am planning on running a fuel filter/pump/filter combo but am having issues visualizing the installation. Additionally, I have two fuel ports on the TBI unit(4.3). Will I need to run 2 pumps/4 filters? Or can I neck both lines down into one and then branch them back out to the TBI unit? Also I know that these tanks need a vent. Would the vent use the filler neck?

Thanks,

Both were "t" into 2 filters, then into one feed with extra coiled hose before the pump. So when low on fuel and on an incline or side bank the engine would not run out of fuel. A vented cap was used.

 

[YJJPWrangler]

So are the two ports on the TBI both input ports, or is there one input port and one return port?

Both ports on the TBI are input ports

Both were "t" into 2 filters, then into one feed with extra coiled hose before the pump. So when low on fuel and on an incline or side bank the engine would not run out of fuel. A vented cap was used.

This is exactly what I needed to know. Thanks!

I’d also consider NOT placing a filter before the pump. From experience, if you clog the first filter, it’ll starve the pump (that’s cooled from flow) and burn it up. Just the one filter, after the pump will suffice.

That is good knowledge to know and I appreciate it. My plan was to do a large micron filter before the pump and then a smaller micron after the pump

A lot of people do a pre-filter of a larger micron rating, mostly to protect the pump from tank debris. The post-pump filter with a smaller micron rating does the important work for the engine downstream.

This is exactly what I had in mind. This is a steel tank and will have a good skid plate on it. Looks like I’m going to the store tomorrow to get parts.

 

[Fabrik8]

Oh, I get it, and I’ve done it. Still do it. Just making the man aware. Deep in the woods, I burnt up a pump, and relied on a buddy’s spare to get me out. Now I roll with a spare. Just info to help make his own decisions.

I think that logic is flawed. The pump is cooled by fuel flow, and can die if overloaded and not cooled properly, like you said. That's a given. I understand what you're saying about killing the fuel pump, but disagree about how to solve it.

But, either an upstream or downstream fuel filter that is clogged can cause the same failure. Either you restrict flow to the pump inlet or the pump exit depending on which filter is clogged, and either way you stall the fuel flow that cools the pump. If you've got enough crap in your fuel tank to clog an upstream fuel filter (before the pump), you're absolutely going to clog a downstream fuel filter (after the pump) if the upstream filter isn't there. Getting rid of the upstream filter doesn't solve the problem, and getting rid of the upstream filter also makes the downstream filter clog faster because now you only have a single filter and that filter has a smaller micron rating than the first filter would have.

 

[YJJPWrangler]

I pulled the fuel gauge sender out and looked into the interior of the tank. Pretty clean for not being used for a long time, no rust was present. I’m going to clean the tank out before I try and start the Jeep. After a tank gets run through it I’ll swap filters just to be sure

 

[Jeff B]

I pulled the fuel gauge sender out and looked into the interior of the tank. Pretty clean for not being used for a long time, no rust was present. I’m going to clean the tank out before I try and start the Jeep. After a tank gets run through it I’ll swap filters just to be sure

It stainless.. you'll find no rust. But you will find a pin hole. Outer bottom right rear corner where its cut off. Just enough to weep fuel. I should have pressure tested it when built it. Little jbweld had fixed it for me.

 

[NC-V]

Both ports on the TBI are input ports

If this is a stock GM TBI unit, both ports are not input ports, the larger is the supply and the smaller is return.

Do either of the ports on the bottom of the tank have a riser pipe? if so use that as the return, but if they are both straight out the bottom of the tank it doesn't matter which is supply/return. If no baffles in tank I would run a coil of line before the pump in case of low fuel to prevent starvation. Also make sure to run a vented cap, that cell looks like it doesn't have a separate vent so the cap will need to vent or you will create a vacuum in the tank and burn up the pump.

 

[rockcity]

Once you figure out your plumbing, start looking at baffling and pickup strategies.

 

[YJJPWrangler]

If this is a stock GM TBI unit, both ports are not input ports, the larger is the supply and the smaller is return.

Do either of the ports on the bottom of the tank have a riser pipe? if so use that as the return, but if they are both straight out the bottom of the tank it doesn't matter which is supply/return. If no baffles in tank I would run a coil of line before the pump in case of low fuel to prevent starvation. Also make sure to run a vented cap, that cell looks like it doesn't have a separate vent so the cap will need to vent or you will create a vacuum in the tank and burn up the pump.

It is a stock GM TBI. That's great information to know, thanks for the insight. Both lines plug into the TBI at roughly the same point(inline with the injectors) and both were labeled left/right fuel lines. Both ports on the tank are on the same level so I should just designate one as the supply and the other as the return correct? The return should run all the way from the engine all the way back to fuel pump with nothing but fuel line correct? I am going to orient the tank so the ports are towards the rear of the jeep for hard acceleration/off camber situations. There are no baffles in the tank right now. Can i use the foam cell and just stuff it in the tank? I will make sure to run a loop in the pipe before the pump to prevent starvation and will run a vented cap.

 

[NCJeeplover]

Can i use the foam cell and just stuff it in the tank?

Alltech's 4x4 fuel cell baffles - Pirate4x4.Com : 4x4 and Off-Road Forum

 

[rockcity]

I’d stay away from foam. Everyone I see talking about foam complains of it breaking down and screwing up the pumps and filters.

I’d look at using an alternate baffle material, such as wiffle balls, corrugated plastic pipe, etc.

 

[NC-V]

If both tank fittings are identical, than it doesn't matter which is supply and which is return. The return line should run directly from the back of the throttle body to the return port in the tank, nothing in between. The pressure regulator is right behind the injector pods where the lines screw in (little zinc plated bowl looking piece). The system only operates at ~12 psi and doesn't require a lot of fuel volume so you don't need any super fancy fuel pump.

 

[YJJPWrangler]

I did a lot of reading l ast night on which fuel pump to go with. Additionally, per @Jeff B post(he was the PO), both of the bottom ports were used as a supply and the return was mounted to the filler neck. This should work(in my head at least). THe return will function correctly and the pump has 2 sources of fuel(both ports "t-ed" into the pump.

 

[Fabrik8]

Do both of the ports come from the tank sidewall right there, or does one of them pickup from another area of the tank? I don't see any reason to use both of them as supply ports if they're identical and right next to each other. Maybe I'm missing something...

 

[Fabrik8]

I’d stay away from foam. Everyone I see talking about foam complains of it breaking down and screwing up the pumps and filters.

I’d look at using an alternate baffle material, such as wiffle balls, corrugated plastic pipe, etc.

The right type of foam works great, but don't buy anything other than FuelSafe or ATL. I think the recommended replacement is every 2 years, so that's probably more maintenance than you want.

Also look into the Holley HydraMat (can't remember the product name), which are really cool and work great. Don't know if that will work without modifying your pickups though.

 

[a_kelley]

You could always run a separate reservoir with dual pumps if starvation becomes an issue. Pump to resevoir and pump to motor. Return motor to resevoir. Return from top of resevoir to tank.

 

[Caver Dave]

It is a stock GM TBI. That's great information to know, thanks for the insight. Both lines plug into the TBI at roughly the same point(inline with the injectors) and both were labeled left/right fuel lines.

GM TBI uses an internal regulator, so one is definitely a return.

I'm running GM TBI on my Commando with an RCI cell... aside from twice in 10 years with near full tanks (once nose up at 80*, the other nose up at 60* & layed on the side) no issues with starvation

 

[Tim C]

You could always run a separate reservoir with dual pumps if starvation becomes an issue. Pump to resevoir and pump to motor. Return motor to resevoir. Return from top of resevoir to tank.

This is what I do. Un-baffled cell, DEFINITELY no cheap foam, mine that came with the cell started breaking down after a year and was a pain in the ass to get cleared up.

I made a surge tank out of a huge diesel screw on filter. I used a low pressure high flow Carter 4070 pump to fill the surge tank/ filter then a e2000 high psi bronco pump to run to the injectors.

I originally ran with just the e2000 and no surge tank but if the cell got below 1/4 tank and you took a hard turn like pulling into or out of the neighborhood it would stall. The diesel filter holds just over 1 quart and the engine return goes to it.

Sent from my HTC6545LVW using Tapatalk