How to Install a FiTech EFI System - 1967 Chevelle
Electronic fuel injection. Remember when guys used to buy cars based on the fact that it still had a carburetor? Or better yet, one that was old enough to not have a catalytic converter? Those days are long gone. Everything now has more computing power than all the Apollo missions combined. Cars are now almost completely computer-controlled, with thousands of other electronic gadgets and doo-dads.
Why would you want to add this kind of complexity to your hot rod, though? Simplest definition, in the most convenient terms? We’ve gotten soft. I’m only partially kidding. My reasons for choosing to dive down the EFI rabbit-hole were all based around the fact that my wife would be driving this car. She’s never daily driven a carbureted vehicle. I’m confident that she could easily manage a well-tuned electric choke. A single pedal stab to set the choke, a slight warmup period as she made it to the edge of our neighborhood and she’d be off to the races. Except, I kind of wanted the late-model EFI luxury too. No more filling the float bowls to restart after a long winter. No stuck floats, no stuck choke, no leaky gaskets. Not to mention, on the fly AFR adjustments as atmosphere and condition changes come along on a long trip. What’s not to like? Plenty. . . but we’ll get to that.
I’ll start where any good story should, at the beginning. This engine had been run in and dynoed at Bluprint’s facility in Kearney, NE shortly before it was crated up and sent to us at Speedway. Since that time, the intake has been taped up. After removing the tape, I found a unisex Spread/Square bore carb flange. Technically, this flange is a-okay to bolt a square bore carb (or TBI) directly to. However, I have experienced some cases where there is a razor-thin contact edge at the widest point of the spread bore cavity between the gasket and respective mating surfaces. This steel adapter plate and gasket will eliminate any chance of misalignment and gasket failure at those critical points.
The installation of the TBI unit itself is fairly straightforward. There are simple hookups for the wiring supplied. This car was planned around using a system like this. So, wiring for the fuel pump, power, fans, and A/C signal were all already routed and planned. Doing this as a retrofit would be a little bit more of a chore depending on how clean you want the wires routed and how many of the added functions you wanted to employ. Like fan switching and auto on when A/C is engaged.
Follow the directions on your particular unit and you should be golden. Route the blue trigger wire far away from your coil and ignition system. I ended up ripping out well-hidden wires to shield this wire with grounded stainless braid in an effort to eliminate suspected RF interference.
The first thing I discovered that makes installation a little different, where the fuel inlet and return ports. They’re both on the back of the unit. If you have unlimited hood clearance, that’s no problem. If you want to use a dropped base air cleaner, problem.
Shown in the photo below is a mockup of fittings I had laying around to try and get the lines down and pointed in the direction I needed them pointed. While also incorporating a pressure gauge at the unit.
Even with extra care taken to shrink the footprint of the unit to a normal carb size, it was impossible to use a normal drop-base air cleaner made for a standard carb. No matter how you clock it, the depressions originally made for your dad’s 4150 Holley float adjusters weren’t in the right place to clear everything. No problem, I’ve got some other tricks up my sleeve for that too. Again, I’ll get to those items too.
The plumbing was also tailored to this unit during the build-up of the rest of the car. Feed and return lines were routed inside the frame and up the front of the engine to give as wide a berth to hot exhaust and other fatal elements. I really can’t say enough good things about the Earl’s Vaporguard line of products. It’s inexpensive, it works and it looks great.
I will write an entire story that details what I’ve found for tuning FiTech through working with this project. But, for now, I will give a few of the biggest pointers I can at this stage of installation.
Top Ten things I learned as a FiTech owner – With a year’s perspective:
- Buy an AC Delco GM water temp sender (PN 35515326386) to replace the one supplied.
- Buy a wideband O2 Sensor Bosch 17014 - to replace the one supplied.
- RF Shield the blue wire from the FiTech unit to your coil (tach signal) to save chasing straw men on the phone with FiTech later.
- DO NOT KEY ON MORE THAN ONCE – The unit primes (very heavily) every time you cycle the key.
- Cut the “PRIME FUEL MULT” setting to -75% from the factory set +259% the very first time you key on. You can enrich it as needed to get better cold starts and not wash hot starts down.
- Forums are your friend, Facebook has numerous forums dedicated to FiTech, Sniper, etc. Check them out before you make a buying decision.
- Change your oil soon after your initial start. Lessen the risk of washed down rings and bearings.
- Buy a unit that your engine fits in the middle of the HP range. i.e. this unit’s range is 200HP to 600HP. It seems like the closer to either extreme, the more issues.
- Route the handheld wires someplace semi-permanent. You’re gonna use it. A lot.
- Save up and buy a sequential port injection system. GM only widely used TBI on production V8’s for a smidge over six years. There’s a reason for that.
