In the fall of 2016 I installed the FiTech GoEFI 600 fuel injection system in my 1978 Corvette. I wanted the more precise Air to Fuel ratio that EFI offers. My current Edelbrock carburetor worked great, but was running very rich and I wasn’t in the mood to start fiddling around with new metering needles and such, when installing the FiTech EFI seemed so easy.

My first decision after purchasing the GoEFI 600 throttle body system, was what type of fuel pump to use. Normally you would install an in-tank fuel pump, that pushes the fuel to the throttle body at the 58PSI that the GoEFI 600 unit needs. This requires dropping the gas tank to install the pump, and running an additional return line to the tank from the throttle body. But, FiTech offers what they call the Fuel Command Centre (FCC), that eliminates all the fuss of an in-tank fuel pump. The FCC is a canister that contains a high pressure fuel pump within it (wet sump). You simply connect your existing low pressure pump to the input of the FCC, and connect the high pressure output to your throttle body. No return line required, although it does require a vent line. FiTech recommends running this vent line back to the gas tank.

Here’s where the story starts. I decided that the FCC makes a lot more sense, allows me to install the EFI system, without major modifications to my numbers matching 1978 C3. If I ever wanted to go back to a carb again, I simply remove the GoEFI throttle body, and replace with carb. All my hookups are all still there.

The first issue was deciding where to put the FCC, with the crowded engine bay of the 78 Vette, there wasn’t a lot of choices. If I didn’t have AC, I could have put it where the AC compressor is, but I didn’t want to remove the AC. It would fit nicely where the vapour canister is, but I didn’t want to remove that either, as I didn’t want a smelly car. I finally decided to put it the only other place it would fit. Between the two bumper brackets in front of the vacuum tank. It fits perfectly there. It was very difficult to get it in there, but once it was there, it was out of sight, far enough away so you wouldn’t hear it, and because it was up front, the air-scoop directed  air on it keeping it cool.

After hooking up the power, low pressure fuel line, and high pressure line to the throttle body, all that was left was to figure out where to put the vent line. I didn’t want the hassle of running a line back to the tank, but I remembered that on the 1978 Corvette, the vapour canister has a connector meant for the fuel bowl vent from the Rochester Carburetor. This is perfect I thought, since the FCC is basically a big fuel bowl. (It even has a float, and needle and seat). I promptly installed the vent to this location. Confirmed all of my other vacuum lines were connected where they were suppose to be (purge lines etc). After getting the FCC primed (that’s another story), the GoEFI system worked like a charm, and I was on the road in no time.

The system worked great, with the exception of a strong fuel smell at times. Initially I didn’t know where the smell was coming from, as everything with the vapour canister was connected properly. After reading online about issues others were having with the FCC, I realized my decision to vent to the vapour canister was a bad one. Apparently the vent line on the FCC does not just vent fumes, it also can occasionally spit out fuel. This is why the instructions tell you to run a line back to the gas tank. Now my dilemma was how to get another line back to the gastank.  On the forums, most other users of the system tap into the filler neck. C3’s don’t have a filler neck, so that option was out. I realized that the fact that the FCC was spitting out fuel into my vapour canister, that unit is basically toast now, and I would have to remove it and replace it. I also found out that that particular style of vapour canister used in 1978 and 1979 Corvettes was no longer available. So now my thinking is starting to wonder about removing the vapour canister completely, and using the existing vent line from the vapour canister to the gas tank as my vent line to the tank from the FCC, and then simply run a vented gas cap. I figured since the vapour canister is no longer there, the tank would need a way to vent, so a vented gas cap would be the only way to go.

After connecting the FCC vent directly to the tank, and venting the gas cap, I took it out for a test drive. Initially it worked great. As I increased RPM, I noticed that occasionally it would stumble and almost quit, then start up again… go for a 1/2 mile or so, and then do it again. I realized what was happening. The fuel that was spitting out of the FCC was temporarily clogging the vent line causing a fuel lock. Once enough pressure built up it would clear the line, and run fine until it clogged again. This is when I had the idea that maybe I shouldn’t vent the gas cap?  My thinking was that the vacuum created in the gas tank while the fuel was being burned might be enough to suck the vent line of any fuel. I pulled over to the side of the road and put the non-venting gas cap on, and voila. It runs perfect.

The lesson I learned was don’t try and outthink the engineers that designed this equipment in the first place. If I had just listened and ran a vent line to the tank in the first place, I would have had zero issues with the FCC.