FITECH EFI 600 Basic and Command center intall with pics, factory tank

[AnotherWs6]

Well I have a whole system and FCC in a box downstairs in my basement. Came across it used and couldn't resist. Any ideas about how to vent this thing on a Suburban?

[Lattimer]

Originally Posted by AnotherWs6

Well I have a whole system and FCC in a box downstairs in my basement. Came across it used and couldn't resist. Any ideas about how to vent this thing on a Suburban?

Here is how I understand it.


The FCC needs a vent. Otherwise it would vapor lock. The problem is is the float in the FCC ever malfunctions, it could send fuel out the vent. So they want the vent plumbed into tank like a return line. The vent needs to be above the fuel level.

I'm not all that familiar with the Suburbans, but if the tank is like most under-body tanks the sending unit should be on the top of the tank. So all you would need to do is remove the sender, drill a hole and either install a bulkhead fitting or weld on a nipple to the sender to attach the vent.

I could do the same on my pickup, but when the tank is full the whole sender is below the level of the fuel in the tank, and according to FiTech thats no good.

So I'm left with the external pump and return option. My concern there is fuel slosh when cornering since the stock tank is not baffled. I'm worried it will sputter when the pickup is uncovered. I think one of those fuel pickup mats from Holley might fix that issue, but I haven't decided to pull the trigger yet. And I have a perfectly good running carb, so spending the $$$ hasn't been a priority yet. Kinda waiting to see more people with some miles on the FiTech to make my decision, and I'm also interested in the new Holley kit.

[LEEVON]

In my '50 chevy I have FiTech and a bone stock cab fuel tank. I returned the line from a corvette filter regulator on the frame back to the stock tank by using the sending unit. The tank is bottom-feed, so I bought a sending unit that has a feed tube, and made a hard line into the cab and right into the sending unit and into the tank. The same could be accomplished by brazing or even a bulkhead fitting in a 67-72 tank sending unit and you wouldn't need a bottom-feed line. Or, get a new tank, weld a bung in the bottom and feed the fuel from there, using the stock sending unit feed line as a return. Not too much money into it that way. I also created a tank vent for pressure and vacuum in the filler neck, down to a filter (for vapor) inside the frame after finding out from three vented caps that none of them could move enough air volume. Yeah, they don't like to be run out of fuel, but neither does a carb...same deal, when you're out your out (found out the hard way already).

[Lattimer]

Originally Posted by LEEVON

In my '50 chevy I have FiTech and a bone stock cab fuel tank. I returned the line from a corvette filter regulator on the frame back to the stock tank by using the sending unit. The tank is bottom-feed, so I bought a sending unit that has a feed tube, and made a hard line into the cab and right into the sending unit and into the tank. The same could be accomplished by brazing or even a bulkhead fitting in a 67-72 tank sending unit and you wouldn't need a bottom-feed line. Or, get a new tank, weld a bung in the bottom and feed the fuel from there, using the stock sending unit feed line as a return. Not too much money into it that way. I also created a tank vent for pressure and vacuum in the filler neck, down to a filter (for vapor) inside the frame after finding out from three vented caps that none of them could move enough air volume. Yeah, they don't like to be run out of fuel, but neither does a carb...same deal, when you're out your out (found out the hard way already).

Yeah, I can do a return that way easy. Some of the later sending units have a return built into them (72 I think). But according to FiTech, that's no good for the vent on the FCC.

I think its been confused a little on this thread between the vent and the return.

The FCC needs a vent, not a return. But they want it vented into the air space above the fuel in the tank "in case". You could just vent it to air, but there is a chance of spilling fuel.

If you do the external pump, you need a return somewhere, whether from the throttle body or use the corvette regulator.

I like the idea of the FCC because it gives me a small "fuel cell" up front that stops the issues associated with fuel slosh in the stock tank. But I don't have a good way of venting that thing to the tank that meets what FiTech says I should have without buying a new tank. The one I have is already new, just not interested in doing it again.

At least with a carb you have the fuel in the bowl. The stock setup will suck air occasionally but the carb isn't as sensitive to it because of the small reserve in the bowl. If you suck air with injection you get a sputtering engine, because there is no reserve. Air in the line means air into the injector.

So I could do your setup pretty easy-----and I still might. I'd probably do a bulkhead fitting into the sending unit I have.

I've been reading a lot about these Holley hydramats: https://www.holley.com/products/fuel...mat/hydramats/

I think adding one of them to the pickup would fix the potential fuel slosh issues.

But just when I had my plan together Holley came out with their low cost fuel injection, so now I'm kind of waiting to see more reviews on that before I make a decision.

[NC_John]

Originally Posted by Lattimer

Yeah, I can do a return that way easy. Some of the later sending units have a return built into them (72 I think). But according to FiTech, that's no good for the vent on the FCC.

I think its been confused a little on this thread between the vent and the return.

The FCC needs a vent, not a return. But they want it vented into the air space above the fuel in the tank "in case". You could just vent it to air, but there is a chance of spilling fuel.

If you do the external pump, you need a return somewhere, whether from the throttle body or use the corvette regulator.

I like the idea of the FCC because it gives me a small "fuel cell" up front that stops the issues associated with fuel slosh in the stock tank. But I don't have a good way of venting that thing to the tank that meets what FiTech says I should have without buying a new tank. The one I have is already new, just not interested in doing it again.

At least with a carb you have the fuel in the bowl. The stock setup will suck air occasionally but the carb isn't as sensitive to it because of the small reserve in the bowl. If you suck air with injection you get a sputtering engine, because there is no reserve. Air in the line means air into the injector.

So I could do your setup pretty easy-----and I still might. I'd probably do a bulkhead fitting into the sending unit I have.

I've been reading a lot about these Holley hydramats: https://www.holley.com/products/fuel...mat/hydramats/

I think adding one of them to the pickup would fix the potential fuel slosh issues.

But just when I had my plan together Holley came out with their low cost fuel injection, so now I'm kind of waiting to see more reviews on that before I make a decision.

I think the FCC is just another component that could fail, is ugly under the hood and adds a LOT of extra plumbing. I didn't have problems with mine but was anxious to get rid of it. (Went LS prior to that happening).

Since I still had the in-cab tank, I bought a 71/72 float assembly for my 70 and used that extra line (vent? Can't remember) for my FCC vent/return line. I just cut it short inside and looped it up to keep it higher than the gas level in a full tank.

Optimal? Not sure. But seemed to work ok.

[Lattimer]

Originally Posted by NC_John

I think the FCC is just another component that could fail, is ugly under the hood and adds a LOT of extra plumbing. I didn't have problems with mine but was anxious to get rid of it. (Went LS prior to that happening).

Since I still had the in-cab tank, I bought a 71/72 float assembly for my 70 and used that extra line (vent? Can't remember) for my FCC vent/return line. I just cut it short inside and looped it up to keep it higher than the gas level in a full tank.

Optimal? Not sure. But seemed to work ok.

Good to hear that it worked.

I can see your point that its another item to fail.